Light weight aggregate

As the demand for the structural members application in the concrete industry is continuously increasing simultaneously many a times it is required to lower the density of concrete enabling light weight which helps in easy handling of the concrete and its members. In this research an experimental endeavour has been made to equate conventional concrete with light weight by partially substituting the coarse aggregate with the pumice stone aggregate in M30 grade mix design. Simultaneously small fibres of Recron3's Polypropylene have been applied to the concrete as a reinforcing medium to minimize shrinkage cracking and improve tensile properties. The coarse aggregate was substituted by the pumice aggregate in 10, 20, 30, 40, and 50 percent and fibres respectively in 0.5, 1, 1.5, 2 and 2.5 percent. The experiment is focused on strength parameters to determine the most favourable optimum percent with respect to conventional concrete.

Agricultural industrial wastes produced after extracting palm oil from palm fruits known as palm kernel shell (PKS) are available in large quantities in Indonesia, Malaysia, Nigeria and other tropical countries. Malaysia is the second largest palm oil producing country in the world. This paper reports the results of an investigation conducted to utilize the PKS as lightweight aggregate to produce grade30 concrete with density of about 1850kg/m 3. The properties of both PKS and crushed granite aggregates were compared. The concrete produced using PKS referred to here after as palm kernel shell concrete (PKSC) and its properties were compared with properties of normal weight concrete (NWC) of grade 30 produced using crushed granite aggregates. The fresh and hardened concrete properties such as density, workability, compressive strength of PKSC and NWC were compared. Further, structural behavior through flexural test was investigated. It has been found that PKSC has produced workable concrete and compressive strength of about 35MPa was obtained within 90 days. The addition of 10% silica fume has effect on both workability and strength. The as-cured density of PKSC was found 22% lower than the NWC. Further, the moment capacity of PKSC beams was found higher than NWC beams. In addition, the mode of failure observed in PKSC was ductile compared to the brittle failure of NWC beams. © 2010 IEEE.

http://eprints.um.edu.my/6069/ 
http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=5649228&tag=1

Disposal of plastic waste in an environment is considered an important issue due to its very low biodegradability and presence in large quantities. Hence, recycled plastic is a major solution. Present investigation melt-densified material used as light weight coarse aggregate in concrete. Melt-Densified Aggregates (MDA) was prepared from post-consumer recycled plastic bags by melting. A comparative study was done with conventional specimens. Melt-Densified Aggregates can be used for partial replacement of aggregates in a concrete mixture. The unit weight of the concrete mix was reduced contributing to light weight structures and ecological sustainability. As much as 60 % of both industrial and urban plastic waste is recycled which obtained from various sources. Hence, MDA solves the 3-fold problem of pollution, light weight structure and economy. Keyword-Polypropylene (PP), Melt Low Densified Plastic (MLDP), Light Weight Aggregate, Recycled Plastic __________________________________________________________________________________________________

In recent years, self-compacting concrete (SCC) has
gained wide use for placement in congested reinforced concrete
structures with difficult casting conditions. For such applications,
the fresh concrete must possess high fluidity and good
cohesiveness. In this present study, the effect of replacing the
cement, fine aggregate and coarse aggregate by constant
replacement of silica fume, Manufactured sand (JSW)
replacement of 0%, 10%, 20%, 30%, 40% and light weight
aggregate replacement of 10%, 15%, for internal curing
respectively and their combinations of various proportions on the
properties of different mixes of M40 grade has been  compared
with normal self compacting concrete by conventional curing
method. In this study fresh property and hardened properties of
the different mixes of concrete were determined. From the
present study the test result showed that for fresh concrete all the
mixes satisfies the EFNORC standard values. For harden
concrete both compressive strength and split tensile strength test
the M9 (30%relpacement FA and15% LWA) M4 (30%
replacement FA and10% LWA) by internally curried concrete at
ambient room temperature mixes gave highest values than the
normal concrete by conventionally curing method.

This paper reports the results of a study conducted to investigate the effect of low volume content of steel fiber on the slump, density, compressive strength under different curing conditions, splitting tensile strength, flexural strength and modulus of elasticity of a grade 35 oil palm shell (OPS) lightweight concrete mixture. The results indicate that an increase in steel fiber decreased the workability and increased the density. All the mechanical properties except the modulus of elasticity (E) improved significantly. The 28. day compressive strength of steel fiber OPS lightweight concrete in continuously moist curing was in the range of 41-45. MPa. The splitting tensile/compressive and the flexural/compressive strength ratio for plain OPS concrete are comparable with artificial lightweight aggregate. The (E) value measured in this study was about 15.5. GPa on average for all mixes, which is higher than previous studies and is in the range of normal weight concrete. Steel fiber can be used as an alternative material to reduce the sensitivity of OPS concrete in poor curing environments. © 2011 Elsevier Ltd.

http://www.sciencedirect.com/science/article/pii/S0261306911001464

FREE DOWNLOAD for 50 DAYS AT: https://authors.elsevier.com/c/1YKca3Q2WYbH-2    In this investigation cork was used as a low density aggregate in the production of ultra-lightweight and low thermal conductivity inorganic polymer (geopolymer) composites. This novel and highly sustainable material, synthesised at room temperature (23 °C), may decrease the energy losses inside buildings, thus contributing to the United Nations development goals regarding energy and climate change. The ultra-low density (260 kg/m3) and low thermal conductivity (72 mW/m K) shown by the cork-composites are the second lowest ever reported for inorganic polymer composites, only being surpassed by that of polystyrene-inorganic polymer composites. However, cork is a fully renewable and sustainable resource, while polystyrene is manufactured from non-renewable fossil fuels, and for that reason our strategy has an additional sustainability advantage. Moreover, the cork-inorganic polymer composites do not release any toxic fume when under fire conditions, which is a major advantage over polymeric-based foams.

The consumption of waste materials in self-compacting concrete (SCC) in the construction industry will not only help to conserve the natural resources but also promote sustainability in preserving the environment. Palm oil clinker (POC) is a waste by-product from the incineration process of oil palm shells and fibres. They are porous and lightweight in nature, which makes them suitable for use as a lightweight aggregate (LWA). In this study, a new procedure was employed to obtain the mix design based on the particle packing (PP) concept to ensure the fresh and hardened properties of SCC are achieved. The actual packing level of aggregate and paste volume is integrated into the proportioning method to obtain the final mix design. The proposed procedure was verified by evaluating the SCC formed for self-compactability and mechanical properties. Based on the overall performance of fresh and hardened properties, it can be deduced that the procedure satisfied the requirements for SCC. The satisfactory results indicate that the mix design can be employed not only for POC but also for a variety of combinations of aggregate. © 2013 Elsevier Ltd.

http://www.sciencedirect.com/science/article/pii/S0261306913010297

This study examines the feasibility of using different lightweight aggregates (LA) and bottom ash as coarse and fine aggregates in concrete with fly ash. The lightweight materials were composed of 3 types, namely pumice, cellular lightweight aggregate and MTEC lightweight aggregate. The tests for physical and mechanical properties of lightweight aggregate concretes (LWAC) were conducted in terms of workability, compressive strength, apparent density, abrasion resistance and absorption. Test results showed that compressive strength of LWAC increased with an increase in apparent density, which is mainly depending on the type of aggregate. The replacement of normal weight sand with bottom ash resulted in a decrease both in density of concrete by 180-225 kg/m 3 and 28-day compressive strength of concrete by 16-26%. Moreover, the use of bottom ash to replace sand in concrete increased the demand for mixing water due to its porosity and shape and to further obtain the required workability. The type and absorption of LA influenced predominantly the water absorption of LWAC. Total replacement of natural sand by bottom ash increased the absorption of the concrete by 63-90%. With regard to abrasion resistance, the abrasion resistance of lightweight aggregate concrete was mainly dependent on the compressive strength of concrete: the higher the strength, the higher the abrasion resistance of LWAC. In addition, the use of bottom ash as a fine aggregate resulted in a lower abrasion resistance of lightweight aggregate concrete due to its porosity. Of the three types of lightweight materials, MTEC LA had achieved both low density and high compressive strength.