Why recycle concrete pavements? The key reasons are cost savings and reduced environmental impact.


Recycling starts with breaking the old pavement. Early jobs used a drop-weight type pavement breaker. Pile driving hammers were used later. Contractors have found that the shape and size of the shoe portion contacting the pavement has significant effect on the way the pavement is broken. Vibratory, sonic, or resonant breakers are used mostly for special purposes.


After cracking the pavement, contractors remove it from the grade and prepare it for transport to the crusher. Some contractors use a backhoe with an attachment at the end called a rhino horn. This horn acts as a ripper to break the reinforcing steel and windrow the broken pavement on the grade.


Paving concretes can be made with significant amounts of recycled fines. However, these fines are more angular, porous, and absorptive than natural sands. This makes the mix more harsh and more difficult to handle and consolidate than it would be otherwise. The coarse fraction of recycled aggregate is primarily used in paving. This material is also is more porous and absorptive than the original aggregates.