纤维和胶粉对水泥砂浆力学和抗裂性能的影响

Effects of Fiber and Rubber Powder on the Mechanical and Crack Resistance of Cement Mortars

温湿度变化、胶凝材料本身变形和结构的约束是引起外墙砂浆开裂的主要原因,研究了3 mm短切耐碱玻璃纤维和可分散胶粉的掺入及掺量对砂浆抗折强度、抗压强度、弹性模量和干燥收缩性能的影响,并制备了914 mm×610 mm×19 mm的自由大板和内环约束的650 mm×800 mm×100 mm试件进行了室外暴露试验。结果表明纤维的掺入能够有效提高砂浆的抗折强度并降低干燥收缩,而胶粉掺入会降低28 d抗压强度并增加砂浆的干燥收缩,但能够降低砂浆的弹性模量,从而提高砂浆的韧性;室外暴露试验显示掺入复合掺入1%纤维和2%的胶粉能够明显提高砂浆的抗裂性能。

The change of temperature and humidity,shrinkage of cementitious material and constraints of structure are mainly causes of mortar for building's exterior wall.Alkali-resistant glass fiber with 3 mm and redispersible emulsion powder were used to investigate the effect on flexural strength,compressive strength,modulus of elasticity and drying shrinkage of mortars.Mortars of slabs(914 mm×610 mm×19 mm)and rings(Φ650 mm×Φ800 mm×100 mm)with inner ring constraint were prepared for outdoor exposure test.The results show that the fiber can improve flexural strength and reduce dry shrinkage effectively.Admixture of emulsion powder will reduce the compressive strength of 28 d and increase the drying shrinkage of the mortar.However,emulsion powder can reduce the modulus of elasticity of mortar and improve the toughness of mortar.Finally,outdoor exposure test shows that the anti-cracking properties of the mortar can be obviously improved by adding 1%fiber and 2%rubber powder.