粉煤灰地聚物前期高温环境对其力学性能的影响

Effect of high temperature environment in the early curing period on mechanical properties of fly ash based geopolymer

为研究粉煤灰地聚物前期养护温度、时长变化及碱激发剂浓度对其力学性能的影响,以3种浓度的NaOH溶液作碱激发剂原料制备硅铝酸盐地聚物,前期高温养护后再室温养护,对试样进行3、7、28 d强度测试,并分析其变化机理。结果表明:3、7 d龄期的地聚物抗压强度变化与初期养护温度、时长及碱浓度呈正相关,60℃养护12 h后3 d时可获得室温环境的4倍强度。室温环境中28 d抗压强度可达42.8 MPa,并且高碱浓度更有利于试样强度的发展,前期高温养护后的试件相比室温强度增长缓慢。增加高温养护时间及温度,有助于试样宏观密实性提高。

In order to study the effects of temperature and duration changes and alkali activator concentration on the mechanical properties of fly ash based geopolymer in the early curing period,three concentrations of NaOH solution were used as the raw material of alkali activator to prepare silicaluminate geopolymer.The samples were cured at high temperature in the early curing period and then at room temperature.The strength of the samples was tested for 3 d,7d and 28 d,and its change mechanism was analyzed.The results showed that the compressive strength of the geopolymers at the age of 3 d and 7d was positively correlated with the initial curing temperature,duration and alkali concentration.After curing at 60℃ for 12 h,the strength of the geopolymers at 3 d was 4 times that at room temperature.In the samples of 28 d,the compressive strength at room temperature could reach 42.8 MPa,and the high alkali concentration was more conducive to the development of sample strength.The strength of the specimens after high temperature curing in the early stage increased slowly compared with that at room temperature.The increase of high temperature curing time and temperature is helpful to improve the macroscopic compactness of the sample.