Improving Crushing Behavior of Construction Demolition Waste Aggregates Using Silica Fume

Exploitation of traditional construction materials like natural crushed stones in road construction poses threats to the environment and its sustainability. On the other hand, increase in construction activities due to rapid industrialization and urbanization has come up with the generation of a large amount of demolition waste which ends up creating problems for the environment. Hence, the use of construction and demolition waste (CDW) as a recycled concrete aggregate in place of crushed stones in pavement construction can be considered as one of the promising methods to manage the CDW, and, at the same time, to protect the natural environment. In this regard, studies on the crushing characteristics of CDW becomes very important. The basic objective of the present study is to improve the crushing characteristics of CDW by mixing it with some suitable admixture. With this in view, one-dimensional compression tests were conducted by applying different stress levels to CDW mixed with different percentages of silica fume (i.e., 0, 5, 10, 15, and 20%) in the form of slurry to the CDW surface. The amount of crushing was calculated by using Hardin’s breakage factor, and the results were found to be very useful. Based upon the present study, the optimum percentage of silica fume can be 15%.