Experimental Study on Shrinkage Performance and Improvement of Cement-Stabilized Recycled Concrete

To investigate the shrinkage properties of cement-stabilized recycled concrete, a systematic study was conducted involving compaction tests, dry shrinkage tests, and temperature shrinkage tests with varying amounts of recycled concrete aggregate (0%, 20%, 40%, 60%, 80%, 100%) and cement dosages (3%, 4%, 5%, 6%). The analysis focused on the evolution of drying shrinkage coefficients with testing age, the variation of thermal shrinkage coefficients with temperature, and the influence of both recycled concrete aggregate content and cement dosage on the total drying shrinkage coefficient and the total thermal shrinkage coefficient. Additionally, the effectiveness of polypropylene fibers in improving shrinkage performance was evaluated. The results indicated that the total drying shrinkage coefficient decreases with an increase in recycled concrete content，whereas the total thermal shrinkage coefficient exhibits a positive correlation with recycled concrete content. Both the total drying shrinkage coefficient and the total thermal shrinkage coefficient were found to increase with the cement dosage. The change in the dry shrinkage coefficient over test days follows a logarithmic curve model. The thermal shrinkage coefficient initially decreases and then increases as the temperature drops, reaching its minimum in the range of 10℃-0℃. The incorporation of polypropylene fibers fibers significantly improves shrinkage properties of cement-stabilized recycled concrete, with the total drying shrinkage coefficient reduced by up to 25.5% and the total thermal shrinkage coefficient by up to 24.1%.