Research on the influence of K-PAM on the microstructure of cement slurry

In this paper, liquid nitrogen freezing and vacuum drying are used to sublimate the water in cement slurry, so that the microstructure of cement slurry can be maintained and the hydration process can be stalled. The microstructure changes of cement slurry containing potassium polyacrylamide (K-PAM) are then observed. The conclusion of the incompatibility mechanism is drawn by comprehensive analysis of the results of the molecular structure of K-PAM, aggregation stability and microstructure of cement slurry. Experimental research shows that a K-PAM molecular chain can adsorb a plurality of cement particles, resulting in an adsorption bridging effect. After reacting with Ca²⁺ in cement slurry, K-PAM turns into polypropylene calcium, which forms a needle-like structure in the cement slurry. Such a needle-like structure is aggregation and staggers to form a net-like structure, causing cement slurry flocculation. Hydrophilic groups of K-PAM and water interact with each other through hydrogen bonding, which forms a layer of solvent membrane on the surface of the cement particles, hindering the contact between water and cement particles. This can reduce the hydration reaction rate, and finally decrease the compressive strength of cement stone.