地质聚合物抗压强度和孔结构的调控研究

Regulation for compressive strength and pore structure of geopolymer

以偏高岭土和水玻璃为原材料,考察H_(2)O/Na_(2)O、Na_(2)O/Al_(2)O_(3)和超声作用对地质聚合物抗压强度的影响,利用氮气吸附法,探讨H_(2)O/Na_(2)O、十六烷基三甲基溴化铵(CTAB)、超声作用对其孔结构的调控规律。结果表明:随H_(2)O/Na_(2)O增加,地质聚合物抗压强度逐渐降低,但利于在其内生成大孔;随着Na_(2)O/Al_(2)O_(3)的增加,强度先提高后降低。超声的起始时间越接近终凝时间,强度越低。掺加CTAB利于生成3~5 nm的孔;与超声起始时间较晚的试样相比,在浆体初凝时间的1/2时超声作用会使120 nm左右的大孔减少,且超声持续时间越长,3~5 nm的凝胶孔越多;超声与CTAB协同作用的试样内部存在较多的40 nm左右的介孔和120 nm左右的大孔,孔形多为圆柱形。

Using metakaolin and water glass as raw materials,the influence of H_(2)O/Na_(2)O,Na_(2)O/Al_(2)O_(3)and ultrasonic action on the compressive strength of geopolymers were investigated,and the regulation of pore structure by H_(2)O/Na_(2)O,cetyltrimethylammonium bromide(CTAB)and ultrasonic action was discussed by nitrogen adsorption method.The results show that with the increase of H_(2)O/Na_(2)O,the compressive strength of geopolymer decreases gradually,but it is beneficial to form large pores.With the increase of Na_(2)O/Al_(2)O_(3),the compressive strength first increases and then decreases.The closer the initial time of ultrasound is to the final setting time,the lower the compressive strength is.The addition of CTAB is conducive to the formation of 3~5 nm pores.Compared with the samples with the later ultrasonic starting time,the ultrasonic action will reduce the large pores around 120 nm when the slurry is 1/2 of the initial setting time,and the longer the ultrasonic duration,the more pores of the gel at 3~5 nm.With the synergistic effect of ultrasound and CTAB,the number of mesopores about 40 nm and large pores about 120 nm appear and the pore shape is mostly cylindrical.