土样矿物成分对固化土抗压强度增长的影响

通过人工制备物理力学性质相同而矿物成分不同的土样,考察相同水泥掺量的固化土抗压强度随土样矿物成分的变化,测定相应固化土孔隙液中主要离子浓度,并进行热力学计算,结果表明土样矿物成分,特别是蒙脱石,影响固化土孔隙液中Ca(OH)2的浓度,进而影响固化土抗压强度。在相同的水泥掺量作用下,含蒙脱石的固化土孔隙液中Ca(OH)2不饱和,随着土样中蒙脱石含量的减少,固化土孔隙液中Ca(OH)2浓度增加,水泥水化生成的胶凝性水化物的量也相应地增多,固化土抗压强度增量也随之提高;当固化土孔隙液中Ca(OH)2浓度达到饱和,土样矿物成分基本不影响固化土抗压强度。并在此基础上使用碱性外掺剂调整固化土孔隙液中Ca(OH)2浓度,试验结果表明:使用碱性外掺剂可以改变固化土孔隙液中Ca(OH)2浓度,减小甚至消除土样矿物成分对固化土孔隙液Ca(OH)2浓度的影响,提高固化土抗压强度。

Effect of mineral component of soil on strength increasing of stabilized soil

At same cement content there existed obviously strength difference between the stabilized soil samples formated from soil samples with different mineral components, which was adjusted manually. In order to find the reason of these experimental results, concentrations of main ions in the pore solutions squeezed from the stabilized soil samples were measured; and the concentrations of Ca(OH)_2 in the pore solutions with many ions were calculated by the thermodynamic method. The result shows that ,at same cement content,when the mineral component of soil samples is montmorillonite, the concentration of Ca(OH)_2 in the pore liquid of the stabilized soil can not reach to saturation; at this stage, the lower the content of montmorillonite is, the more the hydrates generated by cement hydration; therefore the higher the strength of the stabilized soil is; after the concentration of Ca(OH)_2 reach saturation point, the hydrates will fully grow and the strength of the stabilized soil will reach maximum. On the basis of this, the concentration of Ca(OH)_2 in the pore liquid of the stabilized soil was adjusted through alkaline matter; The result shows that alkaline matter can increase the concentration of Ca(OH)_2 in the pore liquid, heighten the strength of the stabilized soil samples.