Enhancing Strength Properties of Rubberized Concrete using Waste Cement Sacks

Low flexibility and brittleness of ordinary concrete limits its use as construction material for buildings prone to earthquake ground vibrations. Rubberized concrete which possesses the needed ductility on the other hand is however of low strength and durability. This study utilized waste polypropylene sacks used for packaging cement. The sacks were used in form of confinements to enhance the strength/ductility of rubberized concrete. Concrete cylinders, cubes and beams at different replacements levels of coarse aggregate with waste tire rubber chips(WTRC) (at 0, 10, 20, 30, 40, 50, 60, 70, 80, 90 and 100% by volumes) were cast and tested for fresh and hardened properties such as slump, compressive strength, flexural strength, and deformation behaviour. The result showed proportional reduction in strengths with increasing replacement of WTRC. Ductile and elasto-plastic deformations were exhibited by WTRC concretes. The use of waste cement sacks confinement as a means of overcoming the reduced strength of the rubberized concrete proved highly feasible and economic for the cylindrical specimens. Optimum performance in failure load (for confined specimens) was obtained at 80% WTRC replacement. The confined 80% WTRC failure load was 45.5 KN, approximately 300% increase in failure load of the unconfined 80% WTRC concrete. This indicates that the use of waste cement sacks to confine rubberized concrete effectively negates the decrease in strength, and retains the advantages of increased ductility and energy-dissipation that characterizes rubberized concrete.