预制构件用水泥基修补砂浆的制备及应用研究

Preparation and application research of cement-based repair mortars for precast concrete elements

为修补预制构件施工过程中缺角、裂缝等缺陷,以硅酸盐水泥、硫铝酸盐水泥和半水石膏作为胶凝体系,掺加适量减水剂、乳胶粉和其他助剂,制备一种凝结时间短、早期强度高的水泥基修补砂浆,并对其性能进行研究。结果表明,掺加减水剂可以提高修补砂浆的抗压强度和流动度,掺加乳胶粉会延长砂浆的凝结时间,降低抗压强度,同时砂浆流动度则随乳胶粉掺量的增加先增大后减小。减水剂掺量以0.20%为宜,乳胶粉掺量以5.0%为宜,此时修补砂浆的初、终凝时间分别为15.8、22.4 min,7、28 d抗压强度分别为32.2、55.1 MPa,流动度为212 mm。

In order to repair defects such as missing corners and cracks in prefabricated component materials during construction,this experiment uses Portland cement,sulfoaluminate cement,and hemihydrate gypsum as the bonding system,and adds an appropriate amount of water reducer,latex powder,and other additives to prepare a cement-based repair mortar with short setting time and high early strength,and studies its performance.The results showed that adding a water reducing agent can improve the compressive strength and flowability of repair mortar.Adding latex powder can prolong the setting time of mortar,reduce compressive strength,and the flowability of mortar increases first and then decreases with the increase of latex powder content.The appropriate dosage of water reducing agent is 0.20%,and the appropriate dosage of latex powder is 5.0%.At this time,the initial and final setting times of the repaired mortar are 15.8 min and 22.4 min,respectively.The compressive strength at 7 d and 28 d is 32.2 MPa and 55.1 MPa,respectively,and the flowability is 212 mm.