养护材料对混凝土强度、抗裂性与细观结构的影响分析

为了探究干寒、大温差环境下最有利于混凝土发展的养护材料,对养护剂、橡塑板和土工布3种材料养护下混凝土的强度、抗裂性以及细观结构进行了分析,并与自然养护进行了对比。结果表明:相较于自然养护形式,养护剂养护下的混凝土的抗压强度较差,然而抗裂性却较好,从细观角度而言,孔隙率、气泡平均弦长都较大,气泡间距系数较小;橡塑板的养护形式与自然养护相比,抗压强度试验结果更好,而抗裂性却更差,细观结构中的孔隙率、气泡平均弦长都较小,气泡间距系数较大;土工布的养护形式综合了其他2种养护形式的优点,抗压强度虽较自然养护无太大变化,但混凝土抗裂性有较大提升,且表征混凝土气孔结构的孔隙率、气泡平均弦长及和气泡间距系数等参数试验结果较好,这也从侧面说明土工布养护下的混凝土具有良好的耐久性。总之,在干寒、大温差的环境下,4种养护方式中土工布包裹养护的形式更有利于混凝土的发展。

Effects of Curing Materials on Strength,Crack Resistance and Mesostructure of Concrete

In an attempt to explore the most suitable curing material for the development of concrete in cold and dry environment with large temperature difference, we analyzed the compressive strength, crack resistance and microstructure of concrete cured by curing agent, rubber sheet and geotextile, respectively, and compared the properties with those under natural condition. Results revealed that in comparison with concrete cured under natural condition, (1) concrete cured with curing agent has inferior compressive strength but superior crack resistance, and in a mesoscopic sense, larger porosity and average chord length but smaller void spacing factor which are used to characterize the pore structure of concrete; (2) concrete cured with rubber sheet has better compressive strength but lower crack resistance, and in a mesoscopic sense, smaller porosity and average chord length but larger void spacing factor; (3) concrete cured with geotextile is endowed with the advantages of the abovementioned two curing methods, with enhanced crack resistance, porosity, average chord length as well as void spacing factor despite no big change in compressive strength, indicating that concrete cured with geotextile is of sound durability. In conclusion, among the four curing methods, geotextile is the most favorable for concrete development in cold and dry environment with large temperature difference.