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为了考察膨胀剂对高延性水泥基复合材料(HDCC)力学性能和变形的影响,研究了掺膨胀剂HDCC的抗折和抗压强度、弯曲韧性、单轴拉伸性能和干燥收缩变形,并采用环境扫描电镜观察了膨胀剂在HDCC中的水化产物形貌。结果表明:膨胀剂对HDCC的抗折强度基本无影响,但略微降低了抗压强度,增大了HDCC的弯曲强度和极限拉伸强度,降低了HDCC的韧性和延性;抗压强度降低幅度在15%以内,极限拉伸应变降低幅度在1/4以内,韧性降低幅度为28%~45%。掺膨胀剂后,HDCC在前2 d有一定的膨胀变形,而长龄期收缩变形值降低了1/4~1/2。膨胀剂水化产生的钙矾石提高了HDCC的体积稳定性。
In order to investigate the effect of expansive agent on the mechanical properties and deformation of high ductility cementitious composites (HDCC), the flexural and compressive strength, flexural toughness, uniaxial tensile properties and dry shrinkage deformation of HDCC with expansive agent were studied. Environmental Scanning Electron Microscopy (SEM) was used to observe the hydration product morphology of the expansive agent in HDCC. The results show that the swelling agent has no effect on the flexural strength of HDCC, but slightly reduces the compressive strength, increases the flexural strength and ultimate tensile strength of HDCC, and decreases the toughness and ductility of HDCC. The compressive strength decreases with Within 15%, the ultimate tensile strain decreases by less than 1/4, and the toughness decreases by 28% ~ 45%. After the expansive agent is added, HDCC has a certain expansion deformation in the first 2 days, while the long-term shrinkage deformation value is reduced by 1/4 ~ 1/2. Ettringite produced by the hydration of an expanding agent increases the volume stability of HDCC.