早强型高延性水泥基复合材料制备及其性能研究

Preparation and Properties of Early-strength High Ductility Cementitious Composites

为满足结构工程对修复材料提出的抗裂、增韧及早强的实际需求,研究了纤维类型、缓凝剂及早强剂对高延性水泥基复合材料(HDCC)的早龄期力学性能、凝结时间与荷载-位移特征的影响。结果表明,不同纤维增强HDCC的24h龄期抗折与抗压强度均分别超过了16,37MPa,表现出早强特征;进口PVA纤维增强HDCC表现出更大的弯曲荷载极大值与对应的跨中位移,国产2种PVA纤维的弯曲荷载极大值相当,跨中位移均小于进口纤维增强体系。缓凝剂则有效延长了凝结时间,早强剂提高了HDCC的抗折强度。将制备的HDCC材料在某桥梁工程箱梁的结构修补中得以应用,取得了良好的抗裂与增韧效果。

In order to meet the actual demand of anti-cracking and toughening in engineering structure repair material, this paper researched the influence of the fiber type, retarder, early-strength agent on the early age mechanical properties and setting time and load-displacement characteristics of high ductility cementitious composites（HDCC）. The results showed that different fiber reinforced HDCC flexural strength and compressive strength were more than 16 MPa and 37 MPa at 24 h age, which showed early strength characteristics. The imported PVA fiber reinforced HDCC showed greater maximum bending load and mid-span displacement corresponding to the two kinds of domestic PVA fiber, then retarder effectively prolonged the setting time, early strength agent could improve the flexural strength of HDCC. The prepared HDCC material was applied to the structural repair of a bridge engineering box girder, and good crack resistance and toughening effect were obtained.