Optimum Percentage of Sawdust and Brick Ballast in Light Weight Concrete

Abstract

Construction industry relies heavily on conventional material such as cement, sand and gravel for the production of concrete The river sand and gravels which are most commonly used as fine aggregates and coarse aggregates respectively in the production of concrete, poses the problem of acute shortage in many areas, whose continued use has started posing serious problem with respect to its availability, cost and environmental impact. Attempt is being made in this project to use the locally available waste materials to replace the river sand and gravels to produce light weight and low cost concrete. Sawdust and Brick ballast are easily affordable at low costs, which are partially replaces with river sand and gravels respectively for making concrete. Natural sand and Gravels have been partially replaced (4% SD 8% BB, 4% SD 16% BB, 4% SD 24% BB, 8% SD 8% BB, 8% SD 16% BB, 8% SD 24% BB, 12% SD 8% BB, 12% SD 16% BB and 12% SD 24% BB. by using M30 grade of concrete) with sawdust and broken brick ballast respectively. For this, thirty concrete cubes of size 150mm X 150mm X 150mm have been casted and water cement ratio of 0.42 has been used. Water reducing admixture is used to increase the workability. Slump test, Compacting factor test and compressive strength at (28 days) of specimens having above combinations have been compared with control specimens. The workability and compressive strength gradually decreases for the increasing the replacement percentages. The optimum mix found to produce M30 grade of concrete is 8% of sawdust and 16% of Brick ballast.