Fresh and hardened properties of cement paste under the synergistic influence of polycarboxylate superplasticizer and anionic polyacrylamide

The combined impact of anionic polyacrylamide (APAM) and polycarboxylate superplasticizer (PCE) on the fresh and hardened properties of cement paste, including rheological properties, setting time, and compressive strength, was investigated. Then the mechanism was further discussed by conducting the experiments of cement hydration and adsorption measurement. The results showed that the increasing dosage of APAM increased the yield stress of cement paste and led to a tendency from shear thickening to shear thinning. This phenomenon was directly connected with the formation of a network structure and hydration products via the bridging effect of adsorbed APAM. The generated hydration products strengthened the network structure over time, leading to a higher structural build-up rate and shorter setting time. Meanwhile, the increasing dosage of APAM increased the adsorption amount of PCE, indicating that PCE still dispersed cement particles and ensured the hydration rate; thus similar compressive strength was observed.