An Experimental Study On The Properties Of Waste Stone Powder Concrete And Of Preplaced Recycled Aggregate Concrete

With the increasing development of cement concrete pavements in our country, various kinds of pavement issues appear. For low-grade pavements, traditional methods of repair require complicated construction techniques and cost lots of manpower and materials. In addition, a large quantity of waste concrete will be produced during pavement repair, leading to environmental pollution. Therefore, the properties of waste stone powder concrete and of prep laced recycled aggregate concrete are studied.A series of tests were performed to study the apparent density, water absorption, and crushing index of natural and recycled coarse aggregates with different sizes to quantify various factors that influence fluidity of grout and to determine the minimum and maximum aggregate diameter used in preplaced recycled aggregate concrete, which provides an experimental evidence for casting preplaced recycled aggregate concrete. A systematic study was made to investigate the effects of the water/cement ratios, sand content, coarse aggregate volume fractions, fly ash content, aggregate type, and mixing process on the compressive strength, abrasion resistance, and drying shrinkage of preplaced recycled aggregate concrete. The effects of the contents of stone powder and chip on the compressive strength were also discussed in brief.The experimental results show that, compared with concrete cast by the traditional mixing process, the preplaced recycled aggregate concrete has low mechanical properties and durability. However, the engineering requirements could be met by optimizing the mix proportion. All the conclusions can provide technical supports for the application of waste stone powder concrete and preplaced recycled aggregate concrete in the rapid repair of cement concrete pavements.