Polymer-modified sulphoaluminate cement-based repair material for high-temperature conditions and its preparation method

Abstract

The present invention provides a polymer-modified sulphoaluminate cement-based repair material for high-temperature conditions and its preparation method. Compared with the prior art, the preparation method of the present invention comprises: S1: grafting ethylene-vinyl acetate copolymer, styrene-acrylate copolymer, or polymethyl methacrylate with epoxy-based, amino-based, or methacryloxy silane coupling agents to prepare a functionalized modified polymer; S2: mixing the modified polymer with sulphoaluminate cement (a compound ratio of expansive type / fast-hardening type being 70:30 to 90:10); S3: further mixing with quartz sand having a particle size of 0.1-2.5 mm (amount being 1.2 times the mass of the cement), a water reducer (0.1%-1.0%), a defoamer (0.01%-0.1%), an expansive agent (1%-3%), and water (30%) to form a repair mortar, followed by curing at 37°C for 28 days. The dosage of the functionalized polymer is 2%-16% of the cement mass. After exposure to high temperatures of 50-70°C for 7-28 days, the compressive strength retention rate is ≥80%, with a flowability of 120-150 mm, an initial setting time of 20-40 min, and a final setting time of 60-120 min.