High-strength self-curing low-shrinkage concrete for pavement applications

Abstract

High-performance concretes (HPC) that are designed to possess high early strength, self-curing capabilities and low shrinkage may potentially improve rigid pavement performance. A multi-scale experimental programme examined mechanical properties and shrinkage behaviour of a low water-to-cementitious materials ratio concrete containing pre-wetted lightweight aggregate for self-curing; results were compared with companion HPC prepared with air-dry lightweight aggregate and with normal weight, normal strength concrete. The use of pre-wetted lightweight aggregate enhanced hydration and strength development during the first year, and limited autogenous shrinkage and substantially reduced drying shrinkage. Digital image analysis revealed that shrinkage was concentrated in the paste rather than in the aggregate in both the normal strength concrete and HPC. The image analysis also showed that strain concentrations at the aggregate/paste interface were less apparent in the HPC, presumably due to the reduced strain mismatch with the use of the lower modulus lightweight aggregate. These observations suggest that the use of HPC containing pre-wetted lightweight aggregate can potentially reduce microcracking and enhance overall pavement performance.

Keywords:

• image analysis
• internal curing
• lightweight aggregate
• moisture
• saturated
• shrinkage

Acknowledgements

The authors gratefully acknowledge support from the Georgia Department of Transportation under Georgia DOT Research Project No. 2041, Task Order No. 02–06. The conclusions expressed herein are those of the authors and do not necessarily represent the opinions or conclusions of the Georgia Department of Transportation.