Investigation of Combined Effect of Mixture Variables on Mechanical Properties of Cement Treated Demolition Waste

One of high efficient ways to reuse the recycled construction and demolition waste (CDW) is to consider it as a road base material. The recycled CDW however is mainly a mix of recycled masonry and concrete with a wide variation in composition. This results that the mechanical properties of cement treated demolition waste are not only determined by cement content and degree of compaction, but also by the composition ratio of masonry to concrete. This paper investigates the combined effect of those three mixture variables on the mechanical properties of cement treated demolition waste by using response surface technique. The evaluated mechanical properties include the unconfined compressive strength (UCS), the elastic modulus and their ratio. Analytical results indicate that increasing the degree of compaction is an economic technique to obtain the required mechanical properties, but it is not an efficient method to enhance the admissible elastic strain (the ratio of UCS to E). Considering the pavement structure design with cement treated demolition base, improvement of its structural performance needs adjusting the masonry content and the cement content