Advanced Technology in Concrete Technology

This Paper describes the possibilities of Metakaolin as one of the mineral admixtures to produce high strength concrete. In this study literature regarding high strength concrete (HSC) and self-curing agents like super absorbent polymers (SAP) was studied. Poly vinyl alcohol and poly acrylic acids are the water soluble polymer has been tried as self-curing agent. The ordinary Portland cement was replaced in varying percentages by using Meta kaolin and found out optimum dose of it which produces high strength concrete. The mechanical property like compressive strength was evaluated. This study is an experimental investigation to determine the effect of polyvinyl alcohol and poly acrylic acid solely on compressive strength of kaolin based concrete at low water cement ratio 0.38. The concrete containing polyvinyl alcohol and poly acrylic acid separately with Meta kaolin enhances mechanical properties, not only due to pozzolanic reaction, but also due to its ability to retain water inside concrete.

Cementitious matrices are the fragile materials that possess a low tensile strength. The addition of fibers randomly distributed in these matrices improves their resistance to cracking, substantially. However, the incorporation of fibers into a plain concrete disrupts the granular skeleton and quickly causes problems of mixing as a result of the loss of mixture workability that will be translated into a difficult concrete casting in site. This study was concerned on the one hand with optimizing the fibers reinforced concrete mixes in the fresh state, and on the other hand with assessing the mechanical behaviour of this mixture in the hardened state, in order to establish a compromise between the two states. In this paper optimization of fibers by using different percentages in steel and glass fiber reinforced concrete of grade M 70 have been studied. It optimizes 1.5% for steel Fiber content and 1% for glass fiber content by the volume of cement is used in concrete.

ABSTRACT Production of cement is ranking 3rd in causes of man-made carbon dioxide emissions world-wide. Thus, in order to make concrete more sustainable one may work along one or more of the following routes; 1) Replacing cement in concrete with larger amounts of supplementary cementing materials (SCMs) than usual, 2) Replacing cement in concrete with combinations of SCMs leading to synergic reactions enhancing strength, 3) Producing leaner concrete with less cement per cubic meter utilizing plasticizers and 4) Making concrete with local aggregate susceptible to alkali silica reaction (ASR) by using cement replacements, thus avoiding long transport of non-reactive aggregate.

Fiber concretes, as a new generations of concrete, have considerably attracted the attention of researchers and engineers for a couple of decades. Fibers play a very important role for improving the weaknesses of concrete, including the tensile and flexural strengths of concrete. In this paper, the effect of length and percentage of steel fibers on the tensile and compressive strengths of concrete is investigated. For this propose, three concrete samples including plain concrete and fiber concretes with steel fibers with lengths of 3 and 5 cm each with different volume ratios (i.e., 0.5, 1, and 1.5%) have been tested. In addition, the samples of the plain concrete are made to determine the effect of fibers on the strength of the concrete. Afterward, using the hydrulic jack machine, both tension and compression strength tests are performed on the concrete specimens.  Based on the obtained results, it is observed that with increasing the length and percentage of steel fibers, the tensile and compressive strengths of the concrete specimens are increased.  Furtheromre, the samples containing a combination of 3 and 5 cm steel fibers in concrete have lower strength than samples with only 5 cm fibers and more strength than samples with only 3 cm fibers.  According to experiments, in order to increase the tensile and compressive strength of concrete, the use of 5 cm steel fibers with different percentages is preferable to 3 cm steel fibers.

Geopolymer concrete is a novel development in concrete technology and still it is developing. In the present investigation, effect of different curing systems on compressive strength of fly ash based geopolymer concrete is highlighted. Three system of curing were considered for study by varying fineness and quantity of fly ash. Two types of low calcium processed flyash were taken from thermal power plant of fineness 600m2/kg and 400m2/kg. Ten geopolymer mixes were prepared and tested for compressive strength using cubes of size 100x100x100 mm. The systems of curing are hot air oven curing, solar oven curing and atmospheric curing. The results shows enhanced compressive strength by solar oven curing as compare to atmospheric temperature curing of geopolymer concrete. Similarly, there is no large variation in compressive strength of geopolymer concrete using Electric oven curing and solar oven curing for fineness of FA 400m²/kg.

3D Printing is technology which has the capacity to elevate additive manufacturing to a new level. This technology has seen development in materials and printing process for over 30 years. It is a technology that is revolutionising the manufacturing industry of today. This Rapid Prototyping (RP) technology is used by designers, architects, film studios and some construction firms to create prototypes for all their needs in a short period of time and at a fraction of the cost of traditional manufacturing techniques like Injection Moulding (IM).
This is a promising technology for use in the construction industry as it has the potential to solve many of the current issues concerning the building industry.(Hager et al., 2016) Compared with traditional technologies 3D printing saves a lot of time and as it is an additive manufacturing technique it also saves wastage of construction materials by only using the required quantity of materials to print a structure. 3D printing is a low energy and resource consuming process which if combined with low-carbon, environment friendly building materials promises to be sustainable in the longer run. (Peng, 2016)
There has been a lot of research regarding 3D printing in various fields including the construction industry. Many researches have demonstrated different aspects of how a 3D printer can be used to build concrete walls and other structural as well as aesthetical elements (Gosselin et al., 2016). There has been a lot of study for making 3D printed objects more stable, durable and resistant to forces of a varying degree ranging from simple picking up of the object to wind loads and improving structural integrity of the printed products (Stava et al., 2012). There have been instances of Architectural and Construction firms building small prototypes and cheap houses from 3D printers which were developed by themselves (DUS Architects) (Architects, 2015) (Architects, 2015) (Architects, 2015) (Architects, 2015) (Architects, 2015) (Architects, 2015). The entirety of these studies/experimentation has been to prove and make parts of the system to make a 3D printed house a reality.
All these studies conclude on various aspects of 3D printing establishing the viability of this system for construction practices of tomorrow but it can be clearly seen that there is absence of a clear system or framework for building sophisticated houses in less time and low cost to the end user.
In this research the existing building technologies for single storey residential houses in Australia, specifically Newcastle region were considered. The time required to build each and every component of the house was studied and the applicability and feasibility of 3D printing to each of these was considered. The major components were divided into 3D printable components and those made by existing technologies. It was found out that making of walls and the frame to support the roof consumed most of the time in building a house. Another major time consuming and expensive part was the layout of services in the house. The capabilities of current day 3D printing technologies and materials was assessed and it was found that the best way to integrate 3D printing in making houses was to build the walls of the house with a 3D printer and integrate the services including water, electricity and also insulation of the house in one system.

History of concrete dates back to 1,200 BC, when reactions between limestone and oil shale during spontaneous combustion occurred in Israel to form a natural deposit of cement compounds. In ancient era cement was not discovered, so Lime was used as an adhesive, to harden and strengthen the construction, was used to construct concrete floors. In modern times, researchers have experimented with the addition of other materials, like water-based cross linking polymers, to create concrete with improved properties, such as higher strength, electrical conductivity, or resistance to damages through spillage. Concrete is a composite material composed of water, coarse granular material embedded in a hard matrix of material (the cement or binder) that fills the space among the aggregate particles and glues them together. In addition, the marble cutting industry generates a high volume of wastes. Recent studies showed that marble waste can be used as construction materials. Index Terms-Marble powder, Compressive strength, Concrete.

This research describes experimental studies on
the utilization of banana trunk fiber to reinforce the strength
and applications of concrete. These natural fibers have
excellent physical and mechanical properties and may be
utilized more effectively. They’re economical, with no
chemicals. The addition of banana fibers significantly
improved many of the engineering properties of the concrete
notably compressive strength, tensile strength and flexural
strength. The flexibility to resist cracking and spalling were
also enhanced. Thus it acts as a natural admixture giving
additional properties to the ordinary cement concrete. During
this context different percentages of banana fibers 0%, 0.5%,
1%, 1.5%, having 50mm length were used. M30 concrete and
ordinary portland cement of grade 43 was used. The banana
fiber reinforced concrete is tested for compressive strength,
splitting tensile strength, flexural strength at different ages.

Key Words: Banana Fibres, natural admixture, High
strength concrete, reinforced concrete

Concrete, second largest consumable material after water, with three tonnes used annually,
makes one of the biggest threats to the sustainability. For example, production of one tonne of cement, 1.7 tonnes of
basic resources (1.6 tons of limestone and clay with 0.1 tons of fuel) are required. Demographic growth, the need
for infrastructure and the dynamism of developing countries is boosting the production of cementing materials over
two billion tons on present scenario and it is growing 5% every year. Therefore, those involved with these industries
must develop new techniques for creating concrete with minimal use of its cement. For this purpose, Supplementary
Cementitious Materials (SCM’s) like Fly Ash (FA), Rice Husk Ash (RHA), Sugar Cane Bagase Ash (SCBA), Palm
Oil Fuel Ash (POFA), etc., are used to blend with cement in concrete in order to increase its properties aspects as
well as solve the environmental related problems. In present investigation an overview on the effect of different
types of Water to Cementitious (W/C) ratio on compressive Strength Active Index (SAI) of unary blended concrete
with different types of ashes are studied in order to understand the SCM’s behaviour in terms of SAI.

This paper describes an attempt to predict the response of shear-critical ECC members that exhibit strong anisotropic stress and strain fields. The ECC members investigated include pre-cracked ECC plates under stress field rotation, orthogonally-reinforced ECC (R/ECC) panel under pure shear, and shear-critical R/ECC beams under reversed cyclic loading. To achieve a simple yet accurate prediction, the mechanics of the ECC are represented by smeared models using a fixed crack approach. The applicability of these models is demonstrated through a simulation of ECC plates and R/ECC panel responses. This demonstrates the importance of an appropriate shear transfer model in representing essential behaviors of ECC in an anisotropic field. Predictions of these models were then compared against experimental results of shear-critical R/ECC beams with a M/Vd ratio of 1.0 and 0.5. For beams with a M/Vd ratio of 1.0, a good agreement is observed in terms of hysteretic response, crack pattern, and failure mechanisms. For beams with a 0.5 M/Vd ratio, the analysis somewhat underestimates the beam capacity, although it does predict a correct failure mechanism. Overall, this paper demonstrates that practical application of nonlinear finite-element analysis to ECC structural members is possible.

Usage of Ground granulated blast furnace slag(GGBS) and silica fume(SF) in the blended concrete alongside ordinary portland cement(OPC) has been in practice owing to low cost of production, denser microstructure leading to enhanced durability with satisfactory strength properties of concrete. The present study focusses on usage of GGBS and Silica Fume in ternary blended mortars. 1:4 and 1:6 mortars are studied for compressive strength at 3,7, and 28 days of age. Results indicated that compressive strength of mortar cubes was at par with that of control mix upto mixes with 30% GGBS and 10% Silica Fume. Cost analysis indicated a decrease in cost of binder from the mixes with 30% GGBS and 10% Silica Fume in comparison with control mix.

3D concrete printing technology is a revolutionary method having multiple benefits over the conventional method of construction. Currently, the 3DCP process is in its initial stage hence required detailed investigation on many points. In the 3DCP process, pumping pressure plays the foremost role as the continuous, uniform and controlled flow of concrete is required to achieve desirable printability. To estimate the pumping pressure effectively, it is necessary to study the pumping parameters & interface friction. The interface friction at boundary layer is largely affected by the concrete composition. The estimation of pumping pressure for conventional concrete was found in past study in which the piston pump and metal pipe was used as a pumping assembly but no work has been found to estimate pumping pressure for 3D printable concrete using progressive cavity pump and high density polyethylene (HDPE) rubber hose pipe. In this study the interface friction between high density polyethylene (HDPE) rubber hose pipe and different 3D printable concrete mix was estimated by performing tribometer test. Effect of 3D printable concrete composition on thickness of boundary layer was also studied. From the experimental results, it was found that the interface friction is decreasing with the more workable concrete mix and the boundary layer (BL) was formed by the cement, water & smaller size of sand particles (<1.18 mm).

The construction industry is growing quickly demanding a huge amount of concrete. The demand for concrete leads to an increased usage of binding material (cement). The need for a huge quantity of cement leads to the depletion of natural sources of which in turn affects the environment. There is a quest to find a suitable material to substitute cement in concrete production. Kaolin powder is material abundant in Ethiopia, which naturally portrays the properties of cementitious material. Thus, this study aimed at exploring the characteristics of this material and its effects on the property of concrete when used as a partial replacement of cement in C-25 concrete production. The kaolin powder was oven-dried and sieved by 150 μm to remove the coarser particle. The percentage of replacement of cement with kaolin powder was varied from 0% to 20% with respect to the cement in incremental steps of 5%. The experimental program was designed to investigate the effect of kaolin powder on the setting time of cement, workability, density, and compressive strength of concrete. The workability of each mix was measured before the specimens cast and cured in water at room temperature and tested at the ages of 7 and 28 days respectively. A total of thirty (30) 150 x 150 x 150mm concrete test cubes were cast using a mix proportion of 1:2:3, with a constant water/cement ratio of 0.6. The result showed that the addition of kaolin powder in cement paste as partial replacement of cement increase both initial and final setting time of cement. However, the workability and density of concrete decrease with the increase of kaolin powder content in the mix. Regarding the compressive strength, increasing the kaolin powder content (up to 10%) the improvement in compressive strength of concrete mixes was continuous. At the curing age of 7 days, the concrete containing 5% and 10% kaolin powder as cement, gained 6.3% and 1.09% of strength while at 15% and 20% replacement level concrete loosed 10.18% and 18.91% of strength respectively. Nevertheless, the replacement of 10% of kaolin powder still improves the compressive strength of concrete as compared to the control concrete, but for much better results, the 5% of kaolin powder was taken as the optimum replacement level Finally, the results encourage the use of kaolin powder as pozzolanic material for partial cement replacement in producing conventional concrete and to compensate for environmental, technical and economic issues caused by cement production.

It is a well-known fact that India is one of the countries with agriculture as its
primary profession. In the recent past, many agro-based industries have been developed and
they continue to grow. Sugarcane industry is one among them. With an increase in the number
of industries, pollution of all sorts has also increased enormously. Sugarcane, which is heated
after being used in the manufacture of sugar, leads to the formation of ash as an industrial
waste known as Sugar Cane Bagasse Ash (SCBA). Since SCBA possesses pozzolanic
properties, it can be used as a partial replacement for cement in concrete, in order to reduce the
emission of Carbon dioxide (CO2) into the atmosphere caused during the production of cement.
In this current research, a Ternary Blended Concrete (TBC) comprising SCBA and Silica Fume
(SF) as the replacement materials for cement has been taken up for study, subjecting it to the
following two conditions: i) elevated temperature and ii) curing under sea water. The above
parameters have been chosen so as to investigate the behavior of TBC with respect to its
resistance to very high temperatures in the incidence of fire accidents and its suitability for
construction in coastal areas. Specimens of concrete mixes were subjected to elevated
temperatures followed by different cooling regimes; various tests were conducted on those
specimens such as compressive test, shrinkage test and sorptivity test. TBC was found to
exhibit better results in all such conditions.

The construction industry is growing quickly demanding a huge amount of concrete. The demand for concrete leads to an increased usage of binding material (cement). The need for a huge quantity of cement leads to the depletion of natural sources of which in turn affects the environment. There is a quest to find a suitable material to substitute cement in concrete production. Kaolin powder is material abundant in Ethiopia, which naturally portrays the properties of cementitious material. Thus, this study aimed at exploring the characteristics of this material and its effects on the property of concrete when used as a partial replacement of cement in C-25 concrete production. The kaolin powder was oven-dried and sieved by 150 μm to remove the coarser particle. The percentage of replacement of cement with kaolin powder was varied from 0% to 20% with respect to the cement in incremental steps of 5%. The experimental program was designed to investigate the effect of kaolin powder on the setting time of cement, workability, density, and compressive strength of concrete. The workability of each mix was measured before the specimens cast and cured in water at room temperature and tested at the ages of 7 and 28 days respectively. A total of thirty (30) 150 x 150 x 150mm concrete test cubes were cast using a mix proportion of 1:2:3, with a constant water/cement ratio of 0.6. The result showed that the addition of kaolin powder in cement paste as partial replacement of cement increase both initial and final setting time of cement. However, the workability and density of concrete decrease with the increase of kaolin powder content in the mix. Regarding the compressive strength, increasing the kaolin powder content (up to 10%) the improvement in compressive strength of concrete mixes was continuous. At the curing age of 7 days, the concrete containing 5% and 10% kaolin powder as cement, gained 6.3% and 1.09% of strength while at 15% and 20% replacement level concrete loosed 10.18% and 18.91% of strength respectively. Nevertheless, the replacement of 10% of kaolin powder still improves the compressive strength of concrete as compared to the control concrete, but for much better results, the 5% of kaolin powder was taken as the optimum replacement level Finally, the results encourage the use of kaolin powder as pozzolanic material for partial cement replacement in producing conventional concrete and to compensate for environmental, technical and economic issues caused by cement production.

Greater confinement of the soil foundation may globally reduce the shear span length, which may raise the risk of shear failure of RC piles. On the other hand, soil confinement may improve the flexural ductility of the pile section locally. This study discusses these global and local impacts of soil confinement on the RC-pile mechanistic behaviors, experimentally and analytically. Small-scale mortar-based piles were newly produced as a mockup of real-scale reinforced concrete so as to obtain the consistent nominal shear strength by reducing the shear transfer along cracks to overcome the size effect. Then, the global impact of soil confinement on pile shear failure is reproduced inside the small-scale experimental devices with soil. The soil-pile interaction test also shows the local impact of soil confinement in terms of increasing the flexural ductility of the miniature pile section by suppressing cover spalling and local buckling of reinforcement. It is confirmed that the coupled...