Strength, Deflection and Cracking Behavior of Concrete Slab Using Demolished Concrete as Coarse Aggregates

Making use of demolished waste of reinforced concrete structures is one of the possibilities of reducing waste management and saving natural aggregates. In this experimental work strength, deflection and cracking behavior of reinforced concrete slabs made with recycled aggregate from demolished concrete waste as partial replacement of natural coarse aggregate is evaluated. The replacement of natural coarse aggregates is done in 50%, 60%, 70% and 80% proportion. To compare the results one batch of slab is cost with 100% natural aggregate. Maximum size of aggregates used is 1". For all batches of concrete 1:2:4 mix with 0.45-0.55 water cement ratio is used. All slabs are tested by applying central point load. Average reduction in load carrying capacity is recorded as 7.1% for 50% replacement of natural aggregates. Maximum deflection recorded is 4.4 mm which is with in allowable limits of ACI 318. Cracking behavior of all slabs is also observed and it is found that cracking pattern remained almost same for all models however reduction in cracking load with increased percentages of recycled aggregate is recorded. Based on result it is concluded that coarse aggregates from demolished concrete can effectively be used in reinforced concrete slabs with 50% replacement of natural aggregate with recycled aggregate from demolished concrete.