不同海拔下引气剂气泡及引气水泥净浆性能研究

Study on performance of air-entraining agent bubble and air-entraining cement paste at different altitudes

试验研究云南巧家(海拔500 m,气压98.7 kPa)和昆明(海拔2050 m,气压82.3 kPa)两地下,三萜皂苷类(SJ-2)和脂肪醇聚氧乙烯醚硫酸钠(AES)2种引气剂水溶液气泡的几何参数、引气水泥净浆、砂浆的表观密度和水泥净浆孔径分布,分析大气压强对引气气泡发育的影响,并分析了其影响机理。结果表明:对于同种引气剂,随着海拔升高,气泡初始尺寸增大;气泡初始尺寸越大,则越不稳定;不同引气剂溶液所形成的气泡几何参数差异较大,SJ-2溶液所形成的气泡比AES更细腻、稳定。随着海拔升高,硬化水泥净浆的表观密度呈略微减小趋势,气孔平均直径增大,而且该趋势随着引气剂掺量的增加而更加显著。

The bubble geometric parameters,apparent density and pore size distribution of air entraining cement paste and mortar in aqueous solution of two kinds of air entraining agents(SJ-2 and AES)in Qiaojia(altitude 500 m,air pressure 98.7 kPa)and Kunming(altitude 2050 m,air pressure 82.3 kPa)were studied.The influence of atmospheric pressure on the development of air entraining bubble was analyzed,and its mechanism was also analyzed.The results show that:for the same air entraining agent,the initial bubble size increases with the increase of altitude;the larger the initial bubble size is,the more unstable it is;the geometric parameters of bubbles formed by different air entraining agent solutions are quite different,and the bubbles formed by triterpenoid saponins(SJ-2)solution are more delicate and stable than those formed by fatty alcohol polyoxyethylene ether sodium sulfate(AES).With the increase of altitude,the apparent density of hardened cement paste decreases slightly,and the average pore diameter increases,which is more significant with the increase of air entraining agent content.