Synthesis Study on Use of Concrete Recycled from Pavement and Building Rubble in the Indiana Highway System

The demolition of buildings and highway pavements in the State of Indiana generates a considerable amount of waste materials. The disposal of these materials causes strain on the existing landfills which are rapidly approaching their full capacity. This study is a synthesis of the information on the use of concrete recycled from pavements and building rubble for use in the Indiana highway system. Test results have shown that recycled pavement concrete made chiefly from broken-up and crushed old concrete aggregate is as good as concrete made from virgin aggregate, and sometimes better. The aggregates made from recycled concrete can be used in other applications besides structural pavement. These include shoulder pavement, road surfacing, fill soil stabilizer, pavement base, sub-base material, and econocrete as well as several other applications which are still being tested. The use of recycled fine aggregates should be carefully monitored and should not be used for the development of medium to high-strength concrete. Fines should also not be used in the sub-base, embankment under abutments, and locations surrounding filters. Economic considerations are the primary reasons for recycling the old portland cement concrete as aggregate in new portland cement concrete pavements, although environmental benefits often are derived as well and may become more important in the future. After analyzing other states findings and conclusions, it is recommended that the Indiana Department of Transportation continue recycling portland cement concrete from pavements and proceed with the implementation of a program for recycling concrete from buildings rubbles.