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2 - Basic Cons Safety and Structural Foundation.pdf

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BASIC CONSTRUCTION SAFETY, CONCRETE AND STRUCTURAL FOUNDATION CE 2202 Lecture
Midterm Exam ● March 12, 2024 – TTh Classes ● March 13, 2024 – MW Classes ● Objective Type and Problem Solving ● Coverage – National Building Code, Basic Construction Methodology, Basic Construction Safety, Concrete, Structural Foundation
Basic Construction Safety 1. Always wear your seatbelt when in a vehicle or heavy equipment. 2. Always inspect equipment and tools. 3. Always use fall protection when working at heights. 4. Stay of out the blind spots of heavy equipment. 5. Never put yourself in the line of fire. 6. Utilize proper housekeeping measures to keep work areas clean. 7. Make sure chemicals are properly labeled and stored. 8. Communicate hazards to others. 9. Stop work when needed to address hazards.
2 - Basic Cons Safety and Structural Foundation.pdf
CEMENT, AGGREGATES, ADDITIVES CEMENT • a binder, a substance that sets and hardens independently, and can bind other materials together • a mixture of calcium silicates and small amounts of calcium aluminates that react with water and cause the cement to set. • most important use is the production of mortar and concrete the bonding of natural or artificial aggregates to form a strong building material that is durable in the face of normal environmental effects
BASIC MINERALS TO MAKE CEMENT LIMESTONE • Cement producers usually locate their plants next to limestone deposits. • They vary considerably in their chemistry and thickness and their suitability for cement manufacturing SHALE • Shale is a pure sedimentary rock made of very fine silt, clay and quarz. • Shale falls in the category of mudstones •Shale is distinguished from other mudstones because it is fissile and laminated •They occur in formations that may be several hundred metres thick
GYPSUM • Gypsum is a soft sulfate mineral composed of calcium sulfate dehydrate • The largest and commercially most important deposits of gypsum and anhydrite occur as beds, which may persist over considerable areas with little change in quality or thickness. •They are frequently interbedded with limestones, shales, mudstones, clays, dolomite, rock salt and locally sylvite. • About 20% of gypsum goes towards cement production.
CEMENT MANUFACTURING PROCESS 1) Extraction • Materials are extracted / quarried / recovered and transported to the cement plant. 2 )Crushing and milling • The raw materials, limestone, shale, silica and iron oxice are crushed and milled into fine powders. 3) Mixing and preheating • The powders are blended (the ‘raw meal’) and preheated to around 900° C using the hot gases from the kiln. The preheating burns off the impurities. 4) Heating • Next the material is burned in a large rotary kiln at 1500° C. Heating starts the de-carbonation where CO2 is driven from the limestone. The partially fused resulting is known as clinker. A modern kiln can produce around 6000 tons of clinker a day. CaCO3 (limestone) + heat -> CaO (lime) + CO2 5) Cooling and final grinding • The clinker is then cooled and ground to a fine powder in a tube or ball mill. A ball mill is a rotating drum filled with steel balls of different sizes (depending on the desired fineness of the cement) that crush and grind the clinker. Gypsum is added during the grinding process to provide means for controlling the setting of the cement. The cement is bagged transported for concrete production.
TYPES OF CEMENT Type 1 – OPC Type 2 – Moderate Heat of Hydration (PPC) Type 3 – Rapid Hardening Cement Type 4 – Low Heat Cement Type 5 – Sulphate Resisting Cement. Non-Hydraulic Cement • cannot harden while in contact with water, as opposed to hydraulic cement which can • created using materials such as non-hydraulic lime and gypsum plasters, and oxy chloride, which has liquid properties • utilized in construction, it must be kept dry in order to gain strength and hold the structure • when used in mortars, those mortars can set only by drying out, and therefore gain strength very slowly • rarely utilized in modern times due to the difficulties associated with waiting long periods for setting and drying Hydraulic Cement • have the ability to set and harden after being combined with water • as a result of chemical reactions, after hardening hydraulic cement mixtures retain strength and stability even when in contact with water • made primarily from limestone, certain clay minerals, and gypsum, which are burned together in a high temperature process that drives off carbon dioxide and chemically combines the primary ingredients into new compounds • The ability to withstand continuous contact with water, in addition to the ability to set and harden quickly, and greater relative strength makes hydraulic cement the main cement utilized in modern day construction.
Portland Cement • The main form of cement used in construction worldwide today is the hydraulic cement called Portland cement • It is a type of hydraulic cement made by heating a limestone and clay mixture to 1450 °C in a kiln and pulverizing the materials. In a process known as calcination, whereby a molecule of carbon dioxide is liberated from the calcium carbonate to form calcium oxide, or quicklime, which is then blended with the other materials that have been included in the mix. • The resulting hard substance, called ‘clinker’, is then ground with a small amount of gypsum into a powder to make ‘Ordinary Portland Cement’, the most commonly used type of cement (often referred to as OPC). • It is a fine, grey or white powder that is made by grinding Portland cement clinker, a limited amount of calcium sulfate which controls the set time, with other minor constituents. • The cement is used as the basic ingredient of concrete, mortar, stucco and most non specialty grout. High alumina cement • High alumina cement is obtained by fusing or sintering a mixture in suitable proportion of alumina and calcareous material and grinding the resultant product to a fine powder. • Raw materials are limestone and bauxite. • About 20% of strength is achieved in one day. Quick Setting Cement • The setting time of ordinary cement is very less if gypsum is not added at the clinkering stage. Therefore when quick setting cement is required, the gypsum is deliberately added in less quantity or not added at all. • This type of cement is useful in flowing water and some typical grouting operations.
PROPERTIES OF CEMENT Chemical Properties • Chemical analysis • Compound composition • Chemical limits Physical Properties • Fineness • Soundness • Consistency • Setting time • False set and flash set • Compressive strength • Heat of hydration • Loss on ignition • Density • Bulk density • Sulfate expansion
TEST FOR CEMENT Fineness Test The fineness of cement can be defined as the measure of size of particles of cement or in simple form “Specific Surface of Cement”. This test is usually carried out using IS sieve no.9 or 90 microns. Setting Time Test Cement when mixed with water triggers a process which results in a hardened mass of mixture wherein hardness gradually increases with time. There are two setting times for cement- Initial Setting Time (IST) or Final Setting Time (FST).It is tested using Vicat’s Apparatus.
ADVANTAGES VS DISADVANTAGES OF CEMENT ADVANTAGES DISADVANTAGES Cement is used as a binding material Cement are subjected to cracking Cement is easy to handle and apply It is very difficult to provide idoneous curing conditions They are suitable to contact with potable water Not ideal for situations when settlement is expected
CEMENT, AGGREGATES, ADDITIVES AGGREGATES • ‘Aggregate’ is a term for any particulate material. It includes coarse particulate rock-like material consisting of a collection of particles ranging in size from < 0.1 mm to > 50 mm. It includes gravel, crushed rock, sand, recycled concrete, slag, and synthetic aggregate. • Aggregates make up some 60 -80% of the concrete mix. They provide compressive strength and bulk to concrete. • Aggregates in any particular mix of concrete are selected for their durability, strength, workability and ability to receive finishes. • For a good concrete mix, aggregates need to be clean, hard, strong particles free of absorbed chemicals or coatings of clay and other fine materials that could cause the deterioration of concrete. • The technique of Sieve Analysis is used for gradation of aggregate for use in concrete and for other applications. • Larger aggregate diameters reduce the quantity of cement and water needed.
COMMON AGGREGATES Crushed Stone and Manufactured Sand • Stone is quarried, crushed and ground to produce a variety of sizes of aggregate to fit both ‘coarse’ and ‘fine’ specifications. GRAVEL • Gravel is formed of rocks that are unconnected to each other. ‘Gravel is composed of unconsolidated rock fragments that have a general particle size range and include size classes from granule- to boulder-sized fragments.’ SAND • Sand occurs naturally and is composed of fine rock material and mineral particles. Its composition is variable depending on the source. It is defined by size, being finer than gravel and coarser than Silt. LIGHTWEIGHT AGGREGATES • Lightweight aggregates can be from natural resources, or they can be man-made.The major natural resource is volcanic material whilst synthetic aggregates are produced by a thermal the thermal treatment of materials with expansive properties.These materials can be divided in three groups—natural materials, such as perlite, vermiculite, clay, shale, and slate; industrial products, such as glass; and industrial by-products, such as fly ash, expanded slag cinder, and bed ash.
RECYCLED CONCRETE • Recycled concrete as aggregate will typically have higher absorption and lower specific gravity than natural aggregate and will produce concrete with slightly higher drying shrinkage and creep. These differences become greater with increasing amounts of recycled fine aggregates. AGGREGATE EXTRACTION • Aggregates are extracted from natural sand or sand-and-gravel pits, hard-rock quarries, dredging submerged deposits, or mining underground sediments. ROCK QUARRIES • The process of extraction from rock quarries usually involves explosives to shift the rock from the working face. Rock is crushed and passed through a series of screens. The output is a range of sizes of rock produced to specified sizes. Crushed rock is transported from quarries by road or rail. MARINE AGGREGATE Between 20 and 30 purpose-built dredging vessels work 24/7 to extract marine aggregate. There are two types of dredging technique: • Static dredging involves a vessel anchoring over and working a deposit using an electronic pump. • A pump is trailed behind the vessel along the seabed.
WATER (AGGREGATE WASHING) • Water is critical in the making of concrete. Adding water to the mix sets off a chemical reaction when it comes into contact with the cement. The water used in the mixing of concrete is usually of a potable standard. Using non-drinking water or water of unknown purity risks the quality and workability of the concrete.
TYPES OF AGGREGATE Coarse Aggregate Coarse-grained aggregates will not pass through a sieve with 4.75 mm openings. Those particles that are predominantly retained on the 4.75 mm sieve and will pass through 3-inch screen, are called coarse aggregate. The coarser the aggregate, the more economical the mix. Larger pieces offer less surface area of the particles than an equivalent volume of small pieces. Use of the largest permissible maximum size of coarse aggregate permits a reduction in cement and water requirements. Using aggregates larger than the maximum size of coarse aggregates permitted can result in interlock and form arches or obstructions within a concrete form. That allows the area below to become a void, or at best, to become filled with finer particles of sand and cement only and results in a weakened area. For Coarse Aggregates in Roads following properties are desirable: 1. Strength 2. Hardness 3. Toughness 4. Durability 5. Shape of aggregates 6. Adhesion with bitumen
Fine Aggregate The other type of aggregates are those particles passing the 9.5 mm (3/8 in.) sieve, almost entirely passing the 4.75 mm sieve, and predominantly retained on the 75 µm sieve are called fine aggregate. For increased workability and for economy as reflected by use of less cement, the fine aggregate should have a rounded shape. The purpose of the fine aggregate is to fill the voids in the coarse aggregate and to act as a workability agent.
PURPOSE AND USES OF AGGREGATE Purpose & Uses of Aggregates In concrete, an aggregate is used for its economy factor, to reduce any cracks and most importantly to provide strength to the structure. 1. Aggregates are used as the base, subbase, and/or surface of roads in several forms 2. In roads and railway ballast, it is used to help distribute the load and assist in ground water running off the road. 3. Increases the volume of concrete, thus reduces the cost. Aggregates account for 60-75% of the volume of concrete and 79-85% weight of PCC 4. Provide dimensional stability 5. Influence hardness, abrasion resistance, elastic modulus and other properties of concrete to make it more durable, strong and cheaper. 6. Other uses include fills, backfills, and drainage and filtration applications.
CEMENT, AGGREGATES, ADDITIVES ADDITIVES • added to the mixture of water cement and aggregate in small quantities to increase the durability of the concrete, control setting, and hardening and fix the general concrete behavior • can be powdered or liquid additives •supplied in ready-to-use liquid form and are added to the concrete at the plant or at the jobsite
TYPES OF CONCRETE ADDITIVES CHEMICAL ADDITIVES MINERAL ADDITIVES ● Reduce the construction cost ● Overcome emergencies at concrete operations. ● Guarantee quality during mixing all through to curation process. ● Modify the features of a hardened concrete ● Increase concrete strength. ● Economize on the mixture ● Reduce the permeability levels. ● Affect the nature of concrete (hardened) through the use of hydraulic activity.
CLASSIFICATION OF ADDITIVES Water reducing They reduce the amount of water used to prepare concrete for a specific slump. Most of these additives are used in larger construction projects. Here, the steel requires higher reinforcing rates to offer the high workability levels needed. Additives in this category are active up to 10% Accelerating additives They accelerate the rate of cement hydration. These additives are most efficient during the cold seasons. Calcium chloride is used as the accelerating additive on non-reinforced concrete. Air-Entrainment These additives are used to introduce microscopic air bubbles to stabilize the concrete. The resultant effect is preventing the concrete from cracking in a cold environment. Air also raises the cohesion force thus reducing segregation and water bleeding before the concrete fully settles.
Shrinkage reducing These additives are used in floor slabs, bridge decks, and buildings where curling and cracks need to be significantly reduced. They provide the durability while maintaining the beautiful nature of the structure. Concrete shrinks occur where there is not adequate water. The shrinks cause internal stresses that may culminate to cracks. The shrinkage additives work to ensure that this does not happen. Corrosion-Inhibiting These additives are used where there is a presence of chloride salts. These chloride ions may corrode with steel reinforcements resulting to rusts. The areas that need this additive most include bridges, parking garages, and marine structures. Super plasticizers They are based on Sulphonated Naphthalene or Melamine formaldehyde condensates, Vinyl polymers or Polycarboxylate Ethers. They are also known as plasticizers or high-range water reducers (HRWR), reduce water content by 12 to 30 percent and can be added to concrete with a low-to- normal slump and water-cement ratio to make high-slump flowing concrete. The effect of Superplasticizers lasts only 30 to 60 minutes, depending on the brand and dosage rate, and is followed by a rapid loss in workability. As a result of the slump loss, Superplasticizers are usually added to concrete at the jobsite.
DESIGN MIXES - is the process of selecting the ingredients for a concrete mixture and deciding on their proportions. When designing a concrete mix, you should always consider the desired strength, durability, and workability of the concrete for the project. - ACI CONCRETE MIX (CE 3103) - For the Laboratory you may follow the basic estimation of concrete mix by Max Fajardo
2 - Basic Cons Safety and Structural Foundation.pdf
2 - Basic Cons Safety and Structural Foundation.pdf
Foundation Piles Pile foundation, a kind of deep foundation, is actually a slender column or long cylinder made of materials such as concrete or steel which are used to support the structure and transfer the load at desired depth either by end bearing or skin friction. Deep foundations. They are formed by long, slender, columnar elements typically made from steel or reinforced concrete, or sometimes timber. A foundation is described as 'piled' when its depth is more than three times its breadth. -Atkinson, 2007
Foundation Pile When to Use Pile Foundation Following are the situations when using a pile foundation system can be ● When the groundwater table is high. ● Heavy and un-uniform loads from superstructure are imposed. ● Other types of foundations are costlier or not feasible. ● When the soil at shallow depth is compressible. ● When there is the possibility of scouring, due to its location near the river bed or seashore, etc. ● When there is a canal or deep drainage systems near the structure. ● When soil excavation is not possible up to the desired depth due to poor soil condition. ● When it becomes impossible to keep the foundation trenches dry by pumping or by any other measure due to heavy inflow of seepage.
Foundation Pile Types of Pile Foundation Pile foundations can be classified based on function, materials and installation process, etc. Followings are the types of pile foundation used in construction: A. Based on Function or Use 1. Sheet Piles 2. Load Bearing Piles 3. End bearing Piles 4. Friction Piles 5. Soil Compactor Piles B. Based on Materials and Construction Method 1. Timber Piles 2. Concrete Piles 3. Steel Piles 4. Composite Piles
Sheet Piles This type of pile is mostly used to provide lateral support. Usually, they resist lateral pressure from loose soil, the flow of water, etc. They are usually used for cofferdams, trench sheeting, shore protection, etc. They are not used for providing vertical support to the structure. They are usually used to serve the following purpose- ● Construction of retaining walls. ● Protection from river bank erosion. ● Retain the loose soil around foundation trenches. ● For isolation of foundation from adjacent soils. ● For confinement of soil and thus increase the bearing capacity of the soil.
Load Bearing Piles This type of pile foundation is mainly used to transfer the vertical loads from the structure to the soil. These foundations transmit loads through the soil with poor supporting property onto a layer which is capable of bearing the load. Depending on the mechanism of load transfer from pile to the soil, load- bearing piles can be further classified as flowed.
End Bearing Piles In this type of pile, the loads pass through the lower tip of the pile. The bottom end of the pile rests on a strong layer of soil or rock. Usually, the pile rests at a transition layer of a weak and strong slayer. As a result, the pile acts as a column and safely transfers the load to the strong layer. The total capacity of end bearing pile can be calculated by multiplying the area of the tip of the pile and the bearing capacity of at that particular depth of soil at which the pile rests. Considering a reasonable factor of safety, the diameter of the pile is calculated.
Friction Pile Friction pile transfers the load from the structure to the soil by the frictional force between the surface of the pile and the soil surrounding the pile such as stiff clay, sandy soil, etc. Friction can be developed for the entire length of the pile or a definite length of the pile, depending on the strata of the soil. In friction pile, generally, the entire surface of the pile works to transfer the loads from the structure to the soil. The surface area of the pile multiplied by the safe friction force developed per unit area determines the capacity of the pile. While designing skin friction pile, the skin friction to be developed at a pile surface should be sincerely evaluated and a reasonable factor of safety should be considered. Besides this one can increase the pile diameter, depth, number of piles and make pile surface rough to increase the capacity of friction pile.
Soil Compactor Piles piles driven at placed closed intervals to increase the bearing capacity of soil by compacting.
Timber Piles Timber piles are placed under the water level. They last for approximately about 30 years. They can be rectangular or circular in shape. Their diameter or size can vary from 12 to 16 inches. The length of the pile is usually 20 times of the top width. They are usually designed for 15 to 20 tons. Additional strength can be obtained by bolting fish plates to the side of the piles. Advantages of Timber Piles- ● Timber piles of regular size are available. ● Economical. ● Easy to install. ● Low possibility of damage. ● Timber piles can be cut off at any desired length after they are installed. ● If necessary, timber piles can be easily pulled out.
Timber Piles Disadvantages of Timber Piles- ● Piles of longer lengths are not always available. ● It is difficult to obtain straight piles if the length is short. ● It is difficult to drive the pile if the soil strata are very hard. ● Spicing of timber pile is difficult. ● Timber or wooden piles are not suitable to be used as end-bearing piles. ● For durability of timber piles, special measures have to be taken. For example- wooden piles are often treated with preservative.
Concrete Piles Pre-cast Concrete Pile The precast concrete pile is cast in pile bed in the horizontal form if they are rectangular in shape. Usually, circular piles are cast in vertical forms. Precast piles are usually reinforced with steel to prevent breakage during its mobilization from casting bed to the location of the foundation. After the piles are cast, curing has to be performed as per specification. Generally curing period for pre-cast piles is 21 to 28 days. Advantages of Pre-cast Piles ● Provides high resistance to chemical and biological cracks. ● They are usually of high strength. ● To facilitate driving, a pipe may be installed along the center of the pile. ● If the piles are cast and ready to be driven before the installation phase is due, it can increase the pace of work. ● The confinement of the reinforcement can be ensured. ● Quality of the pile can be controlled. ● f any fault is identified, it can be replaced before driving. ● Pre-cast piles can be driven under the water. ● The piles can be loaded immediately after it is driven up to the required length.
Concrete Piles Disadvantages of Pre-cast Piles ● Once the length of the pile is decided, it is difficult to increase or decrease the length of the pile afterward. ● They are difficult to mobilize. ● Needs heavy and expensive equipment to drive. ● As they are not available for readymade purchase, it can cause a delay in the project. ● There is a possibility of breakage or damage during handling and driving of piles. Cast-in-Palace Concrete Piles This type of pile is constructed by boring of soil up to the desired depth and then, depositing freshly mixed concrete in that place and letting it cure there. This type of pile is constructed either by driving a metallic shell to the ground and filling it with concrete and leave the shell with the concrete or the shell is pulled out while concrete is poured.
Concrete Piles Advantages of Cast-in-Place Concrete Piles ● The shells are light weighted, so they are easy to handle. ● Length of piles can be varied easily. ● The shells may be assembled at sight. ● No excess enforcement is required only to prevent damage from handling. ● No possibility of breaking during installation. ● Additional piles can be provided easily if required. Disadvantages of Cast-in-Place Concrete Piles ● Installation requires careful supervision and quality control. ● Needs sufficient place on site for storage of the materials used for construction. ● It is difficult to construct cast in situ piles where the underground water flow is heavy. ● Bottom of the pile may not be symmetrical. ● If the pile is un-reinforced and uncased, the pile can fail in tension if there acts and uplifting force.
Concrete Piles
Steel Piles Steel piles may be of I-section or hollow pipe. They are filled with concrete. The size may vary from 10 inches to 24 inches in diameter and thickness is usually ¾ inches. Because of the small sectional area, the piles are easy to drive. They are mostly used as end-bearing piles. Advantages of Steel Piles ● They are easy to install. ● They can reach a greater depth comparing to any other type of pile. ● Can penetrate through the hard layer of soil due to the less cross-sectional area. ● It is easy to splice steel piles ● Can carry heavy loads. Disadvantage of Steel Piles ● Prone to corrosion. ● Has a possibility of deviating while driving. ● Comparatively expensive.
Composite Piles Composite Piles are those piles of two different materials are driven one over the other, so as to enable them to act together to perform the function of a single pile. In such a combination, advantage is taken of the good qualities of both the materials. These prove economical as they permit the utilization of the great corrosion resistance property of one material with the cheapness or strength of the other.
TYPES OF FOOTINGS 1. SPREAD FOOTING is defined as the structural members used to support the column and walls as well as transmit and distribute the load coming on the structure to the soil beneath it.
2. STRAP FOOTING is also a type of shallow foundation, consisting of two or more column footings connected by a concrete beam. This type of beam is called a strap beam. 3. COMBINED FOOTING is basically a combination of various footings, which utilizes the properties of different footing in a single footing based on the requirement of the structure. It carries two or more columns along a straight line.
4. STRIP FOOTING is a type of shallow foundation that is used to provide a continuous, level strip of support to a linear structure.
5. MAT FOOTING It is a large slab supporting a number of columns and walls under an entire structure or a large part of the structure.
FOOTING FORMWORKS
What is Formworks? ● In construction, formwork is the use of support structures and moulds to create structures out of concrete which is poured into the moulds. ● Formwork can be made using moulds out of steel, wood, aluminum, and/or prefabricated forms.
Footing Formworks ● Formworks for foundation ● Foundation can be for columns or walls. So, based on type of structural member, the shape and size of footing are designed. Thus formwork size and shape depends on the type and dimension of the footing.
Materials Used Formwork are mainly of two types: ● Wooden formwork ○ Lumber (2” x 2” x 12” or 2” x 2” x 8” or 2” x 3” x 12”) ○ Plywood ○ Common wirenails (CWN) ● Steel formwork ○ Steel sheets ○ Angle Iron ○ Tee Iron Wooden Formwork Steel Formwork
Components of Footing Forms:

More Related Content

2 - Basic Cons Safety and Structural Foundation.pdf

  • 2. Midterm Exam ● March 12, 2024 – TTh Classes ● March 13, 2024 – MW Classes ● Objective Type and Problem Solving ● Coverage – National Building Code, Basic Construction Methodology, Basic Construction Safety, Concrete, Structural Foundation
  • 3. Basic Construction Safety 1. Always wear your seatbelt when in a vehicle or heavy equipment. 2. Always inspect equipment and tools. 3. Always use fall protection when working at heights. 4. Stay of out the blind spots of heavy equipment. 5. Never put yourself in the line of fire. 6. Utilize proper housekeeping measures to keep work areas clean. 7. Make sure chemicals are properly labeled and stored. 8. Communicate hazards to others. 9. Stop work when needed to address hazards.
  • 5. CEMENT, AGGREGATES, ADDITIVES CEMENT • a binder, a substance that sets and hardens independently, and can bind other materials together • a mixture of calcium silicates and small amounts of calcium aluminates that react with water and cause the cement to set. • most important use is the production of mortar and concrete the bonding of natural or artificial aggregates to form a strong building material that is durable in the face of normal environmental effects
  • 6. BASIC MINERALS TO MAKE CEMENT LIMESTONE • Cement producers usually locate their plants next to limestone deposits. • They vary considerably in their chemistry and thickness and their suitability for cement manufacturing SHALE • Shale is a pure sedimentary rock made of very fine silt, clay and quarz. • Shale falls in the category of mudstones •Shale is distinguished from other mudstones because it is fissile and laminated •They occur in formations that may be several hundred metres thick
  • 7. GYPSUM • Gypsum is a soft sulfate mineral composed of calcium sulfate dehydrate • The largest and commercially most important deposits of gypsum and anhydrite occur as beds, which may persist over considerable areas with little change in quality or thickness. •They are frequently interbedded with limestones, shales, mudstones, clays, dolomite, rock salt and locally sylvite. • About 20% of gypsum goes towards cement production.
  • 8. CEMENT MANUFACTURING PROCESS 1) Extraction • Materials are extracted / quarried / recovered and transported to the cement plant. 2 )Crushing and milling • The raw materials, limestone, shale, silica and iron oxice are crushed and milled into fine powders. 3) Mixing and preheating • The powders are blended (the ‘raw meal’) and preheated to around 900° C using the hot gases from the kiln. The preheating burns off the impurities. 4) Heating • Next the material is burned in a large rotary kiln at 1500° C. Heating starts the de-carbonation where CO2 is driven from the limestone. The partially fused resulting is known as clinker. A modern kiln can produce around 6000 tons of clinker a day. CaCO3 (limestone) + heat -> CaO (lime) + CO2 5) Cooling and final grinding • The clinker is then cooled and ground to a fine powder in a tube or ball mill. A ball mill is a rotating drum filled with steel balls of different sizes (depending on the desired fineness of the cement) that crush and grind the clinker. Gypsum is added during the grinding process to provide means for controlling the setting of the cement. The cement is bagged transported for concrete production.
  • 9. TYPES OF CEMENT Type 1 – OPC Type 2 – Moderate Heat of Hydration (PPC) Type 3 – Rapid Hardening Cement Type 4 – Low Heat Cement Type 5 – Sulphate Resisting Cement. Non-Hydraulic Cement • cannot harden while in contact with water, as opposed to hydraulic cement which can • created using materials such as non-hydraulic lime and gypsum plasters, and oxy chloride, which has liquid properties • utilized in construction, it must be kept dry in order to gain strength and hold the structure • when used in mortars, those mortars can set only by drying out, and therefore gain strength very slowly • rarely utilized in modern times due to the difficulties associated with waiting long periods for setting and drying Hydraulic Cement • have the ability to set and harden after being combined with water • as a result of chemical reactions, after hardening hydraulic cement mixtures retain strength and stability even when in contact with water • made primarily from limestone, certain clay minerals, and gypsum, which are burned together in a high temperature process that drives off carbon dioxide and chemically combines the primary ingredients into new compounds • The ability to withstand continuous contact with water, in addition to the ability to set and harden quickly, and greater relative strength makes hydraulic cement the main cement utilized in modern day construction.
  • 10. Portland Cement • The main form of cement used in construction worldwide today is the hydraulic cement called Portland cement • It is a type of hydraulic cement made by heating a limestone and clay mixture to 1450 °C in a kiln and pulverizing the materials. In a process known as calcination, whereby a molecule of carbon dioxide is liberated from the calcium carbonate to form calcium oxide, or quicklime, which is then blended with the other materials that have been included in the mix. • The resulting hard substance, called ‘clinker’, is then ground with a small amount of gypsum into a powder to make ‘Ordinary Portland Cement’, the most commonly used type of cement (often referred to as OPC). • It is a fine, grey or white powder that is made by grinding Portland cement clinker, a limited amount of calcium sulfate which controls the set time, with other minor constituents. • The cement is used as the basic ingredient of concrete, mortar, stucco and most non specialty grout. High alumina cement • High alumina cement is obtained by fusing or sintering a mixture in suitable proportion of alumina and calcareous material and grinding the resultant product to a fine powder. • Raw materials are limestone and bauxite. • About 20% of strength is achieved in one day. Quick Setting Cement • The setting time of ordinary cement is very less if gypsum is not added at the clinkering stage. Therefore when quick setting cement is required, the gypsum is deliberately added in less quantity or not added at all. • This type of cement is useful in flowing water and some typical grouting operations.
  • 11. PROPERTIES OF CEMENT Chemical Properties • Chemical analysis • Compound composition • Chemical limits Physical Properties • Fineness • Soundness • Consistency • Setting time • False set and flash set • Compressive strength • Heat of hydration • Loss on ignition • Density • Bulk density • Sulfate expansion
  • 12. TEST FOR CEMENT Fineness Test The fineness of cement can be defined as the measure of size of particles of cement or in simple form “Specific Surface of Cement”. This test is usually carried out using IS sieve no.9 or 90 microns. Setting Time Test Cement when mixed with water triggers a process which results in a hardened mass of mixture wherein hardness gradually increases with time. There are two setting times for cement- Initial Setting Time (IST) or Final Setting Time (FST).It is tested using Vicat’s Apparatus.
  • 13. ADVANTAGES VS DISADVANTAGES OF CEMENT ADVANTAGES DISADVANTAGES Cement is used as a binding material Cement are subjected to cracking Cement is easy to handle and apply It is very difficult to provide idoneous curing conditions They are suitable to contact with potable water Not ideal for situations when settlement is expected
  • 14. CEMENT, AGGREGATES, ADDITIVES AGGREGATES • ‘Aggregate’ is a term for any particulate material. It includes coarse particulate rock-like material consisting of a collection of particles ranging in size from < 0.1 mm to > 50 mm. It includes gravel, crushed rock, sand, recycled concrete, slag, and synthetic aggregate. • Aggregates make up some 60 -80% of the concrete mix. They provide compressive strength and bulk to concrete. • Aggregates in any particular mix of concrete are selected for their durability, strength, workability and ability to receive finishes. • For a good concrete mix, aggregates need to be clean, hard, strong particles free of absorbed chemicals or coatings of clay and other fine materials that could cause the deterioration of concrete. • The technique of Sieve Analysis is used for gradation of aggregate for use in concrete and for other applications. • Larger aggregate diameters reduce the quantity of cement and water needed.
  • 15. COMMON AGGREGATES Crushed Stone and Manufactured Sand • Stone is quarried, crushed and ground to produce a variety of sizes of aggregate to fit both ‘coarse’ and ‘fine’ specifications. GRAVEL • Gravel is formed of rocks that are unconnected to each other. ‘Gravel is composed of unconsolidated rock fragments that have a general particle size range and include size classes from granule- to boulder-sized fragments.’ SAND • Sand occurs naturally and is composed of fine rock material and mineral particles. Its composition is variable depending on the source. It is defined by size, being finer than gravel and coarser than Silt. LIGHTWEIGHT AGGREGATES • Lightweight aggregates can be from natural resources, or they can be man-made.The major natural resource is volcanic material whilst synthetic aggregates are produced by a thermal the thermal treatment of materials with expansive properties.These materials can be divided in three groups—natural materials, such as perlite, vermiculite, clay, shale, and slate; industrial products, such as glass; and industrial by-products, such as fly ash, expanded slag cinder, and bed ash.
  • 16. RECYCLED CONCRETE • Recycled concrete as aggregate will typically have higher absorption and lower specific gravity than natural aggregate and will produce concrete with slightly higher drying shrinkage and creep. These differences become greater with increasing amounts of recycled fine aggregates. AGGREGATE EXTRACTION • Aggregates are extracted from natural sand or sand-and-gravel pits, hard-rock quarries, dredging submerged deposits, or mining underground sediments. ROCK QUARRIES • The process of extraction from rock quarries usually involves explosives to shift the rock from the working face. Rock is crushed and passed through a series of screens. The output is a range of sizes of rock produced to specified sizes. Crushed rock is transported from quarries by road or rail. MARINE AGGREGATE Between 20 and 30 purpose-built dredging vessels work 24/7 to extract marine aggregate. There are two types of dredging technique: • Static dredging involves a vessel anchoring over and working a deposit using an electronic pump. • A pump is trailed behind the vessel along the seabed.
  • 17. WATER (AGGREGATE WASHING) • Water is critical in the making of concrete. Adding water to the mix sets off a chemical reaction when it comes into contact with the cement. The water used in the mixing of concrete is usually of a potable standard. Using non-drinking water or water of unknown purity risks the quality and workability of the concrete.
  • 18. TYPES OF AGGREGATE Coarse Aggregate Coarse-grained aggregates will not pass through a sieve with 4.75 mm openings. Those particles that are predominantly retained on the 4.75 mm sieve and will pass through 3-inch screen, are called coarse aggregate. The coarser the aggregate, the more economical the mix. Larger pieces offer less surface area of the particles than an equivalent volume of small pieces. Use of the largest permissible maximum size of coarse aggregate permits a reduction in cement and water requirements. Using aggregates larger than the maximum size of coarse aggregates permitted can result in interlock and form arches or obstructions within a concrete form. That allows the area below to become a void, or at best, to become filled with finer particles of sand and cement only and results in a weakened area. For Coarse Aggregates in Roads following properties are desirable: 1. Strength 2. Hardness 3. Toughness 4. Durability 5. Shape of aggregates 6. Adhesion with bitumen
  • 19. Fine Aggregate The other type of aggregates are those particles passing the 9.5 mm (3/8 in.) sieve, almost entirely passing the 4.75 mm sieve, and predominantly retained on the 75 µm sieve are called fine aggregate. For increased workability and for economy as reflected by use of less cement, the fine aggregate should have a rounded shape. The purpose of the fine aggregate is to fill the voids in the coarse aggregate and to act as a workability agent.
  • 20. PURPOSE AND USES OF AGGREGATE Purpose & Uses of Aggregates In concrete, an aggregate is used for its economy factor, to reduce any cracks and most importantly to provide strength to the structure. 1. Aggregates are used as the base, subbase, and/or surface of roads in several forms 2. In roads and railway ballast, it is used to help distribute the load and assist in ground water running off the road. 3. Increases the volume of concrete, thus reduces the cost. Aggregates account for 60-75% of the volume of concrete and 79-85% weight of PCC 4. Provide dimensional stability 5. Influence hardness, abrasion resistance, elastic modulus and other properties of concrete to make it more durable, strong and cheaper. 6. Other uses include fills, backfills, and drainage and filtration applications.
  • 21. CEMENT, AGGREGATES, ADDITIVES ADDITIVES • added to the mixture of water cement and aggregate in small quantities to increase the durability of the concrete, control setting, and hardening and fix the general concrete behavior • can be powdered or liquid additives •supplied in ready-to-use liquid form and are added to the concrete at the plant or at the jobsite
  • 22. TYPES OF CONCRETE ADDITIVES CHEMICAL ADDITIVES MINERAL ADDITIVES ● Reduce the construction cost ● Overcome emergencies at concrete operations. ● Guarantee quality during mixing all through to curation process. ● Modify the features of a hardened concrete ● Increase concrete strength. ● Economize on the mixture ● Reduce the permeability levels. ● Affect the nature of concrete (hardened) through the use of hydraulic activity.
  • 23. CLASSIFICATION OF ADDITIVES Water reducing They reduce the amount of water used to prepare concrete for a specific slump. Most of these additives are used in larger construction projects. Here, the steel requires higher reinforcing rates to offer the high workability levels needed. Additives in this category are active up to 10% Accelerating additives They accelerate the rate of cement hydration. These additives are most efficient during the cold seasons. Calcium chloride is used as the accelerating additive on non-reinforced concrete. Air-Entrainment These additives are used to introduce microscopic air bubbles to stabilize the concrete. The resultant effect is preventing the concrete from cracking in a cold environment. Air also raises the cohesion force thus reducing segregation and water bleeding before the concrete fully settles.
  • 24. Shrinkage reducing These additives are used in floor slabs, bridge decks, and buildings where curling and cracks need to be significantly reduced. They provide the durability while maintaining the beautiful nature of the structure. Concrete shrinks occur where there is not adequate water. The shrinks cause internal stresses that may culminate to cracks. The shrinkage additives work to ensure that this does not happen. Corrosion-Inhibiting These additives are used where there is a presence of chloride salts. These chloride ions may corrode with steel reinforcements resulting to rusts. The areas that need this additive most include bridges, parking garages, and marine structures. Super plasticizers They are based on Sulphonated Naphthalene or Melamine formaldehyde condensates, Vinyl polymers or Polycarboxylate Ethers. They are also known as plasticizers or high-range water reducers (HRWR), reduce water content by 12 to 30 percent and can be added to concrete with a low-to- normal slump and water-cement ratio to make high-slump flowing concrete. The effect of Superplasticizers lasts only 30 to 60 minutes, depending on the brand and dosage rate, and is followed by a rapid loss in workability. As a result of the slump loss, Superplasticizers are usually added to concrete at the jobsite.
  • 25. DESIGN MIXES - is the process of selecting the ingredients for a concrete mixture and deciding on their proportions. When designing a concrete mix, you should always consider the desired strength, durability, and workability of the concrete for the project. - ACI CONCRETE MIX (CE 3103) - For the Laboratory you may follow the basic estimation of concrete mix by Max Fajardo
  • 28. Foundation Piles Pile foundation, a kind of deep foundation, is actually a slender column or long cylinder made of materials such as concrete or steel which are used to support the structure and transfer the load at desired depth either by end bearing or skin friction. Deep foundations. They are formed by long, slender, columnar elements typically made from steel or reinforced concrete, or sometimes timber. A foundation is described as 'piled' when its depth is more than three times its breadth. -Atkinson, 2007
  • 29. Foundation Pile When to Use Pile Foundation Following are the situations when using a pile foundation system can be ● When the groundwater table is high. ● Heavy and un-uniform loads from superstructure are imposed. ● Other types of foundations are costlier or not feasible. ● When the soil at shallow depth is compressible. ● When there is the possibility of scouring, due to its location near the river bed or seashore, etc. ● When there is a canal or deep drainage systems near the structure. ● When soil excavation is not possible up to the desired depth due to poor soil condition. ● When it becomes impossible to keep the foundation trenches dry by pumping or by any other measure due to heavy inflow of seepage.
  • 30. Foundation Pile Types of Pile Foundation Pile foundations can be classified based on function, materials and installation process, etc. Followings are the types of pile foundation used in construction: A. Based on Function or Use 1. Sheet Piles 2. Load Bearing Piles 3. End bearing Piles 4. Friction Piles 5. Soil Compactor Piles B. Based on Materials and Construction Method 1. Timber Piles 2. Concrete Piles 3. Steel Piles 4. Composite Piles
  • 31. Sheet Piles This type of pile is mostly used to provide lateral support. Usually, they resist lateral pressure from loose soil, the flow of water, etc. They are usually used for cofferdams, trench sheeting, shore protection, etc. They are not used for providing vertical support to the structure. They are usually used to serve the following purpose- ● Construction of retaining walls. ● Protection from river bank erosion. ● Retain the loose soil around foundation trenches. ● For isolation of foundation from adjacent soils. ● For confinement of soil and thus increase the bearing capacity of the soil.
  • 32. Load Bearing Piles This type of pile foundation is mainly used to transfer the vertical loads from the structure to the soil. These foundations transmit loads through the soil with poor supporting property onto a layer which is capable of bearing the load. Depending on the mechanism of load transfer from pile to the soil, load- bearing piles can be further classified as flowed.
  • 33. End Bearing Piles In this type of pile, the loads pass through the lower tip of the pile. The bottom end of the pile rests on a strong layer of soil or rock. Usually, the pile rests at a transition layer of a weak and strong slayer. As a result, the pile acts as a column and safely transfers the load to the strong layer. The total capacity of end bearing pile can be calculated by multiplying the area of the tip of the pile and the bearing capacity of at that particular depth of soil at which the pile rests. Considering a reasonable factor of safety, the diameter of the pile is calculated.
  • 34. Friction Pile Friction pile transfers the load from the structure to the soil by the frictional force between the surface of the pile and the soil surrounding the pile such as stiff clay, sandy soil, etc. Friction can be developed for the entire length of the pile or a definite length of the pile, depending on the strata of the soil. In friction pile, generally, the entire surface of the pile works to transfer the loads from the structure to the soil. The surface area of the pile multiplied by the safe friction force developed per unit area determines the capacity of the pile. While designing skin friction pile, the skin friction to be developed at a pile surface should be sincerely evaluated and a reasonable factor of safety should be considered. Besides this one can increase the pile diameter, depth, number of piles and make pile surface rough to increase the capacity of friction pile.
  • 35. Soil Compactor Piles piles driven at placed closed intervals to increase the bearing capacity of soil by compacting.
  • 36. Timber Piles Timber piles are placed under the water level. They last for approximately about 30 years. They can be rectangular or circular in shape. Their diameter or size can vary from 12 to 16 inches. The length of the pile is usually 20 times of the top width. They are usually designed for 15 to 20 tons. Additional strength can be obtained by bolting fish plates to the side of the piles. Advantages of Timber Piles- ● Timber piles of regular size are available. ● Economical. ● Easy to install. ● Low possibility of damage. ● Timber piles can be cut off at any desired length after they are installed. ● If necessary, timber piles can be easily pulled out.
  • 37. Timber Piles Disadvantages of Timber Piles- ● Piles of longer lengths are not always available. ● It is difficult to obtain straight piles if the length is short. ● It is difficult to drive the pile if the soil strata are very hard. ● Spicing of timber pile is difficult. ● Timber or wooden piles are not suitable to be used as end-bearing piles. ● For durability of timber piles, special measures have to be taken. For example- wooden piles are often treated with preservative.
  • 38. Concrete Piles Pre-cast Concrete Pile The precast concrete pile is cast in pile bed in the horizontal form if they are rectangular in shape. Usually, circular piles are cast in vertical forms. Precast piles are usually reinforced with steel to prevent breakage during its mobilization from casting bed to the location of the foundation. After the piles are cast, curing has to be performed as per specification. Generally curing period for pre-cast piles is 21 to 28 days. Advantages of Pre-cast Piles ● Provides high resistance to chemical and biological cracks. ● They are usually of high strength. ● To facilitate driving, a pipe may be installed along the center of the pile. ● If the piles are cast and ready to be driven before the installation phase is due, it can increase the pace of work. ● The confinement of the reinforcement can be ensured. ● Quality of the pile can be controlled. ● f any fault is identified, it can be replaced before driving. ● Pre-cast piles can be driven under the water. ● The piles can be loaded immediately after it is driven up to the required length.
  • 39. Concrete Piles Disadvantages of Pre-cast Piles ● Once the length of the pile is decided, it is difficult to increase or decrease the length of the pile afterward. ● They are difficult to mobilize. ● Needs heavy and expensive equipment to drive. ● As they are not available for readymade purchase, it can cause a delay in the project. ● There is a possibility of breakage or damage during handling and driving of piles. Cast-in-Palace Concrete Piles This type of pile is constructed by boring of soil up to the desired depth and then, depositing freshly mixed concrete in that place and letting it cure there. This type of pile is constructed either by driving a metallic shell to the ground and filling it with concrete and leave the shell with the concrete or the shell is pulled out while concrete is poured.
  • 40. Concrete Piles Advantages of Cast-in-Place Concrete Piles ● The shells are light weighted, so they are easy to handle. ● Length of piles can be varied easily. ● The shells may be assembled at sight. ● No excess enforcement is required only to prevent damage from handling. ● No possibility of breaking during installation. ● Additional piles can be provided easily if required. Disadvantages of Cast-in-Place Concrete Piles ● Installation requires careful supervision and quality control. ● Needs sufficient place on site for storage of the materials used for construction. ● It is difficult to construct cast in situ piles where the underground water flow is heavy. ● Bottom of the pile may not be symmetrical. ● If the pile is un-reinforced and uncased, the pile can fail in tension if there acts and uplifting force.
  • 42. Steel Piles Steel piles may be of I-section or hollow pipe. They are filled with concrete. The size may vary from 10 inches to 24 inches in diameter and thickness is usually ¾ inches. Because of the small sectional area, the piles are easy to drive. They are mostly used as end-bearing piles. Advantages of Steel Piles ● They are easy to install. ● They can reach a greater depth comparing to any other type of pile. ● Can penetrate through the hard layer of soil due to the less cross-sectional area. ● It is easy to splice steel piles ● Can carry heavy loads. Disadvantage of Steel Piles ● Prone to corrosion. ● Has a possibility of deviating while driving. ● Comparatively expensive.
  • 43. Composite Piles Composite Piles are those piles of two different materials are driven one over the other, so as to enable them to act together to perform the function of a single pile. In such a combination, advantage is taken of the good qualities of both the materials. These prove economical as they permit the utilization of the great corrosion resistance property of one material with the cheapness or strength of the other.
  • 44. TYPES OF FOOTINGS 1. SPREAD FOOTING is defined as the structural members used to support the column and walls as well as transmit and distribute the load coming on the structure to the soil beneath it.
  • 45. 2. STRAP FOOTING is also a type of shallow foundation, consisting of two or more column footings connected by a concrete beam. This type of beam is called a strap beam. 3. COMBINED FOOTING is basically a combination of various footings, which utilizes the properties of different footing in a single footing based on the requirement of the structure. It carries two or more columns along a straight line.
  • 46. 4. STRIP FOOTING is a type of shallow foundation that is used to provide a continuous, level strip of support to a linear structure.
  • 47. 5. MAT FOOTING It is a large slab supporting a number of columns and walls under an entire structure or a large part of the structure.
  • 49. What is Formworks? ● In construction, formwork is the use of support structures and moulds to create structures out of concrete which is poured into the moulds. ● Formwork can be made using moulds out of steel, wood, aluminum, and/or prefabricated forms.
  • 50. Footing Formworks ● Formworks for foundation ● Foundation can be for columns or walls. So, based on type of structural member, the shape and size of footing are designed. Thus formwork size and shape depends on the type and dimension of the footing.
  • 51. Materials Used Formwork are mainly of two types: ● Wooden formwork ○ Lumber (2” x 2” x 12” or 2” x 2” x 8” or 2” x 3” x 12”) ○ Plywood ○ Common wirenails (CWN) ● Steel formwork ○ Steel sheets ○ Angle Iron ○ Tee Iron Wooden Formwork Steel Formwork