中文摘要：

研究讨论了裂缝宽度为0.01、0.02 mm的砂浆试块在不同浓度Na_2SO_4溶液中养护28 d后的愈合情况,初步探讨了裂缝在Na_2SO_4溶液中的自愈合机理。结果表明：Na_2SO_4溶液养护相对清水养护有助于0.01 mm以下裂缝愈合;裂缝宽度达到0.02 mm时,随着Na_2SO_4溶液浓度的增加裂缝先愈合后开裂。主要原因在于随着裂缝变宽,Na_2SO_4溶液与未水化水泥颗粒的接触几率增加,Na_2SO_4溶液浓度的升高有利于钙矾石等水泥水化产物大量集中生成,当水化产物生成适量时对裂缝愈合有利,而其生成过量时,水化产物对裂缝两侧的膨胀应力会导致已初步愈合裂缝再次开裂。

英文摘要：

It mainly discussed the self - healing results of 0.01 mm and 0.02 mm mortar cracks under different concentration of Na2 SO4 solution after curing 28 d.The mechanism of cracks self- healing studied preliminary. The research results show that Na2 SO4 solution makes contribution to cracks which width below 0.01ram healing relative to clean water.When the crack width increases to 0.02 mm, with the increasing of the concentration of Na2 SO4 solution the cracks heal at first but crack again. The main reason is that with the cracks getting wider the Na2SO4 solution has more chances to meet unhydrated cement.Because of the increasing of the concentration of Na2SO4 solution, a large number of ettringites and cement hydration products produce. The cracks heal only on the condition of defined amount of hydration products.The excess hydration products would make the cracks craze again because of its expansion.