Effect of Rubber Aggregate on Mechanical Proerties of Concrete

Abstract

This work on “Effect of Rubber Aggregate on Mechanical Properties of concrete” comprises a thesis undertaken to partially fulfill the requirement of the Master Degree course in Structural Engineering at IOE, Pulchowk Campus ( T.U.).

The rubberized concrete has high toughness, durability, sound insulation and energy absorption in order to reduce damage in case of stroke, but lower value of compressive and tensile strength. The aim of this research work was to study the effect of content of rubber aggregate on mechanical properties of concrete for its application on structural and non-structural members. Two types of cement OPC and PPC are being used separately with rubber aggregate and its effect on strength was also observed. The plain rubber aggregate was coated with cement paste and an experiment was carried out to study its effect on mechanical properties of concrete.

This report presents the Unit Weight, Workability and Strength (Compressive, Tensile and Flexural) Properties of concrete containing 0%, 10%, 25% and 40% of rubber aggregate by volume as a replacement of mineral aggregate. The primary data obtained from material test results was considered for mix design of laboratory test specimens. Cubes were tested under direct compression and Cylinders & Beams were tested under indirect tension to study the effect.

The study shows that the rubberized concrete can be finished closed to the same standard as plain concrete with some additional effort. However, workability in the mix is reduced while increasing the content of rubber aggregate. Coating the rubber aggregate increases the workability. The unit weight of rubberized concrete is found to be decreased but still higher than the value of light-weight concrete. The result shows that the incorporation of rubber aggregate into concrete mixes produces a significant reduction in compressive and tensile strength of concrete. The result shows a beneficial effect regarding the flexural strength at lower content of rubber aggregate. It is observed that coating the rubber aggregate with cement paste reduces the percentage reduction of strength and have some better results.

 A rigorous study of previous research work shows that the rubberized concrete has better capacity in absorbing significant plastic energy and withstanding large deformation, high resistance to Impact, improved durability, and improved acoustic and thermal insulation. The current study shows that the use of rubber aggregate is limited to 10% by volume of mineral aggregate to prevent too great loss in mechanical properties of concrete. It is finally concluded that the rubberized concrete containing 10% rubber aggregate can be used at least in non- primary structures such as road and bridge barriers, wall panels (concrete block).