土样pH值对固化土抗压强度增长的影响研究

使用化学试剂改变土样的pH值,不同pH值的土样在等量水泥作用下,固化土抗压强度存在显著的差异。为解释上述试验现象,测定了相应固化土孔隙液中主要离子的浓度,并进行热力学计算。结果表明:在相同的水泥掺量作用下,pH值较低的土样形成的固化土孔隙液中Ca(OH)2不饱和,随土样PH值的增加,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浓度由不饱和逐渐变为饱和后,固化土中胶凝性水化物能充分生成,固化土抗压强度达到最大值,且随土样pH值的增加固化土抗压强度基本保持恒定。

Effect of pH value of soil on strength increasing of the stabilized soil

Under the same cement content,there existed obvious strength differences between the stabilized soil samples formed from soil samples with different pH values,which was adjusted through chemical agent.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.It was shown that,under the same cement content,when the pH value of soil samples was low,the concentration of Ca(OH)2 in the pore liquid of the stabilized soil could not reach saturation;at this stage,the higher the pH of soil was,the more the hydrates generated by cement hydration,therefore the higher the strength of the stabilized soil was;after the concentration of Ca(OH)2 reached the saturation point,the hydrates would fully grow and the strength of the stabilized soil would reach the maximum.