Evaluation of compressive strength and density of rubber sludge waste treated with ordinary portland cement via stabilisation and solidification technique

Abstract

The untreated rubber sludge waste from industries lead to environmental pollution and human health. The high heavy metals content in rubber sludge waste can leached out to surrounding during heavy rains and flash floods, and in the end flows to our water bodies. The treatment of waste by using stabilization and solidification (S/S) is crucial to reduce or prevent the leaching of heavy metals towards surrounding. A study was carried out to evaluate the compressive strength of concrete with different curing time which were 7 and 28 days. Two different sample condition being tested which were dry sample and immersed sample in order to compare the possible hydration process occur in the sample which lead to a better compressive strength. The determination of density development for each sample was performed by calculations and the analyses of heavy metals content by using X-ray fluorescence (XRF) in rubber sludge waste, ordinary Portland cement and Batch R2 had been done. Based on the result obtained, the lower the rubber sludge waste content in sample, the higher its compressive strength and bring to higher density development due to less excessive water and less porosity occur in the hardened sample. The highest universal compressive strength (UCS) at 7 and 28 days is achieved at Batch R2 while the lowest is achieved at Batch R6. The immersed sample shows higher compressive strength compare to dry sample due to hydration process of cement. There were 17 and 15 types of heavy metals contained in ordinary Portland cement and rubber sludge waste respectively. Five main heavy metals such as Aluminium (Al), Titanium (Ti), Vanadium (V), Iron (Fe), Copper (Cu) has been analysed and focussed since they were the high percentage contain in the sample tested. All those heavy metals is toxic that can bring to environmental pollution and affect human health.