Use of Crushed Gravel in Concrete Paving

Project Description

The Texas Department of Transportation has used siliceous river gravel (SRG) aggregates for many years in the construction of continuously reinforced concrete (CRC) pavement, but these pavements have been very expensive to maintain and repair. This project:

• developed a test protocol to measure the bond strength between coarse aggregate and mortar,
• determined measures or practices that can be applied to improve delamination resistance and spalling performance of the gravel concrete in CRC paving, and
• provided guidelines and recommendations to minimize early-age delamination in SRG-CRC paving.

Texas Transportation Institute researchers found that with the appropriate combination of materials and methods, most coarse aggregate deficiencies relative to bonding improve. The aggregate-paste interfacial bond for any given cement depends on combined effects of the physical, chemical, and geometric aggregate properties of the mixture. Research showed that quality control of the curing process may be the most feasible means to minimize early delamination in the field.

This project established a potential step-by-step process of selecting from construction options when using gravel aggregates in concrete paving. More case studies are needed to calibrate the probability of delamination based on wind speed, curing quality, and construction practice. Such future research is vital in establishing threshold values for different levels of probability of delamination and calibrating the associated statistical curves.

Project Publications

Best Practices for the Use of Siliceous River Gravel in Concrete Paving 0-4826-1

Use of Crushed Gravel in Concrete Paving 0-4826-S

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