Most of the Portland cement concrete (PCC) pavements built in the 1950's and 1960's are approaching the end of their structural lives, and some of them need rehabilitation in the form of "remove and replace". From environmental and cost considerations, it would be desirable to reuse the crushed concrete back into the new construction. In 1995, the Texas Department of Transportation (TxDOT) began reconstruction in Houston on a section of IH-10 and the unique aspect of this project was the use of crushed concrete as both coarse and fine aggregates in the new concrete. No virgin aggregates were used. The properties of RCA are consistent with those reported elsewhere: low specific gravity, higher water absorption, sulfate soundness loss, LA abrasion loss, and thermal coefficient. Little variation was observed in the paving operation due to the use of 100 % recycled coarse and fine aggregates. The moisture control of recycled aggregate, especially fine aggregate, is critical in producing consistent and workable concrete. The performance of the reconstructed pavement has been excellent, with tight crack widths and little spalling. Significant differences exist between concretes with RCA and virgin aggregates in modulus of elasticity, and strength. The low modulus of RCA concrete and good bond between recycled coarse aggregates and new mortar appear to be the key ingredients for good pavement performance. Based on the excellent performance, TxDOT revised the specifications in 2004 that allow the use of recycled concrete as coarse aggregate in paving concrete.
|Number of pages||6|
|State||Published - 2007|
|Event||5th International Conference on Maintenance and Rehabilitation of Pavements and Technological Control, MAIREPAV 2007 - Park City, United States|
Duration: Aug 8 2007 → Aug 10 2007
|Conference||5th International Conference on Maintenance and Rehabilitation of Pavements and Technological Control, MAIREPAV 2007|
|Period||08/8/07 → 08/10/07|