复合缓凝剂对高强磷酸镁修补砂浆性能的影响

本文研究了一元缓凝体系和二元复合缓凝体系对高强磷酸镁修补砂浆凝结时间、流动性能和力学性能的影响。结果表明:在一元缓凝体系中,与硼砂和三聚磷酸钠相比,单掺蔗糖的缓凝效果最优,但蔗糖掺量过高会显著降低磷酸镁修补砂浆的流动性能和早期力学性能;在二元复合缓凝体系中,硼砂和蔗糖组成的二元缓凝体系的缓凝效果优于硼砂和三聚磷酸钠组成的二元缓凝体系,在硼砂5%(质量分数)和蔗糖2.5%(质量分数)时,磷酸镁修补砂浆的凝结时间达到18 min,流动度为230 mm,1.5 h、3 d和28 d强度分别为22.6 MPa、56.8 MPa和62.4 MPa,实现了磷酸镁修补砂浆在凝结时间和早期强度之间的动态平衡。

Effect of Complex Retarder on Properties of High Strength Magnesium Phosphate Repair Mortar

The effects of unitary retarder system and binary complex retarder system on setting time, fluidity and mechanical properties of high strength magnesium phosphate repair mortar were studied. The results show that in unitary retarder system, compared with borax and sodium tripolyphosphate, the retardation effect of sucrose alone is the best. But excessive content of sucrose significantly reduces the fluidity and early mechanical properties of magnesium phosphate repair mortar. In the binary complex retarder system, the retardation effect of borax and sucrose is better than borax and sodium tripolyphosphate. Under 5% (mass fraction) borax and 2.5% (mass fraction) sucrose, the setting time of magnesium phosphate repair mortar reaches 18 min, the fluidity is 230 mm, and the strength of 1.5 h, 3 d and 28 d is 22.6 MPa, 56.8 MPa and 62.4 MPa, respectively. The setting time and early strength of magnesium phosphate repair mortar achieve dynamic balance.