Predicting compressive strength of cement-based materials containing water-absorbent polymers considering the internal-curing region

Abstract

The water-absorbent polymer will bring large holes and the internal-curing region for cement-based materials. These two effects will bring negative and positive effects on the compressive strength of the cement-based material, respectively. In this paper, a calculation model of the compressive strength of cement-based materials with water-absorbent polymers was proposed considering the influence of the large holes and internal-curing on the compressive strength. A method for determining the internal-curing width of water-absorbent polymers based on backscattering image analysis was established. Based on the internal-curing width, the compressive strength was predicted and compared with the results of experiments. In addition, the influences of the internal-curing width, size, dosage, mass swelling rate, and volume swelling rate of water-absorbent polymers on the compressive strength were analyzed. The results show that the internal-curing width of the water-absorbent polymers with a mass swelling ratio of 4.22 g/g is about 13 µm. Based on the internal-curing width obtained by characterization, the compressive strength obtained by model is 7 % greater than that obtained by experiments. Besides, the influence range of the internal-curing width, size, and mass swelling ratio of the water-absorbent polymers on the compressive strength is between 80 Mpa and 90 Mpa. The influence range of the dosage and the volume swelling rate of the water-absorbent polymers on the compressive strength is between 20 Mpa and 90 Mpa. The compressive strength is mainly related to the dosage and the volume swelling rate of water-absorbent polymers. The larger the dosage and volume swelling rate are, the smaller the compressive strength is.