Impact of Filler on Engineering Characteristics of Bituminous Paving Mixes with Recycled Concrete Aggregates

As the result of an increase in infrastructure activity, a huge amount of mostly concrete demolition waste has accumulated and is causing concern in regard to its disposal. At the same time, available natural stone reserves of resources are quickly depleting. In pavements only, natural aggregates (NA) are used to the extent of 90-95 % by weight. Keeping this in mind, paving engineers have explored the use of alternate resources to ease not only the construction costs but to also preserve the natural stone resources to the greatest extent possible. Considering this, an attempt has been made in this study to explore the use of crushed materials of available concrete waste, referred to in this article as recycled concrete aggregates (RCA) in bituminous paving mixes. In this article, densely graded bituminous mixes, such as dense bituminous macadam mixes, have been prepared using RCA as a coarse aggregates with both cement (CM) and stone dust (SD) as fillers. Conventional mixes with NA have also been made under similar situations and a comparative study has been made with respect to the engineering properties of these mixes such as Marshall characteristics, indirect tensile strength, moisture sensitivity, and dynamic modulus. It is observed that the RCA mixtures, in general, fulfill all the requirements of Marshall and moisture sensitivity criteria. It is also observed that the mixes that use CM as a filler have better engineering properties compared with those that use SD.