Abstract:Three kinds of hydrophobically modified polyethers with HLB values of 17.5, 15.6 and 11.7 were introduced into the polymer with acrylic acid as main chain, and three polymers SR-PCA1, SR-PCA2, SR-PCA3 with weight-average molecular weight of 25000~30000 were synthesized. Otherwise, the effect of HLB on drying shrinkage and dispersion was investigated, and shrinkage-reducing polycarboxylate superplasticizer SR-PCA2 was developed. By addition of 0.4% SR-PCA2, the water-reducing rate is about 20% and the drying shrinkage of concrete decreases by 25.7%. The contradiction between adsorption dispersion and low surface tension is resolved, and the dispersion, dispersion maintaining and low drying shrinkage are consistent under low dosage by SR-PCA2. The relationship between HLB, surface tension, alkali ions concentration and adsorption behavior was studied, and the mechanism of shrinkage-reducing polycarboxylate superplasticizer was revealed.