Assessment and Comparison of Mechanical Properties of Concrete Incorporating Fine Recycled Concrete Aggregates and Brick Dust

Abstract

Concrete is most commonly used construction material all over the world, over ten billion metric tons of concrete is used yearly for different construction purposes. Concrete is a composite material made of three basic materials i.e. Cement, Coarse aggregates and Fine aggregates. Due to heavy consumption of concrete all over the world, there is a large demand for aggregates, but the availability of these natural aggregates is diminishing so to meet the demand of booming Urbanization we need to use recycled aggregates for production of concrete. It is considered that using recycled aggregates is a viable alternative to dumping which is favorable to the sustainability of natural resources and will help in conservation of natural resources. In the present postgraduate thesis, a study on a comparative study of the mechanical properties of concrete made by replacement of fine aggregates with fine recycled concrete aggregates and crushed brick aggregates. The proportion to which fine aggregates are replaced is 25% and 50%. The free water-cement ratio was kept constant for all the mixes. Results show different Mechanical properties which include compressive strength, flexural strength, splitting tensile strength, modulus of elasticity, ultrasonic pulse velocity, and rebound hammer test. Compressive strength test and splitting tensile strength test are done after 7-Days and 28-days of age while other tests are done at 28-days of age. Test results indicate that all strength properties were reduced, reduction of strength properties increased with increase in replacement ratios. The reduction of the strength properties was more in case of brick dust. It is seen that on 25% replacement of concrete with Fine recycled concrete aggregates it shows favorable results but if the replacement ratio is increased the strength reduction increases which can not be permitted. Reduction in strength properties of mixes incorporating fine recycled brick aggregates was more than fine recycled concrete aggregates and brick dust was not considered a suitable alternative material.