烧料礓石改性遗址土裂隙注浆材料龄期性能试验研究

Experimental study on age properties of fissure grouting material composed of calcined ginger nuts and earthen site soil

为探究土遗址裂隙注浆的适宜材料,选择烧料礓石与遗址土作为主要浆材。基于土遗址体力学强度及浆材流动性试验,确定3种不同浆液配比及水灰比。根据浆体在裂隙注浆工程中的实际工作条件,对浆液结石体进行室外土体掩埋养护,测试其龄期物理力学性质,观察显微结构。结果显示,结石体基本物理性质在养护前3 d受含水率影响显著,龄期3~8 d呈线性变化,龄期8~18 d为过渡阶段,龄期18 d后保持稳定;收缩率、波速、孔隙率、抗折强度和抗压强度随烧料礓石配比增加而增大,密度、渗透系数反之;结石体硬化过程具有初期水化反应提高强度快,后期碳化反应持续时间长,并且物理性质稳定的特点。SEM揭示钙质胶结在土颗粒间的存在形态,增强了骨架颗粒间的黏结力。EDS分析进一步显示随烧料礓石配比增加,结石体中钙元素和碳元素的含量逐渐增高。研究初步表明,烧料礓石改性遗址土适宜作为土遗址裂隙注浆材料。

In order to explore the suitable materials of filling the fissures of earthen sites, The calcined ginger nuts and the soil from the earthen site were selected as the main materials of grout. Three different types of proportions and water-cement ratios were determined based on the mechanical experiments of earthen sites and the fluidity tests on slurry. Considering about the actual working conditions, the grout concretion was buried outside and then its physical and mechanical properties during the different curing age were measured, and simultaneously, its microstructure was observed. The basic physical properties of concretion were influenced significantly by the moisture content of grout in the first three days, then changed linearly from the third to the eighth days before transition phase from the eighth to the eighteenth days, and finally remained stable after eighteen days. The shrinkage rate, wave velocity, porosity, fiexural strength and compressive strength of concretion increased with the growth of the content of calcined ginger nuts, while the density and the permeability coefficient showed an opposite trend. During the hardening process, the hydration reaction contributed to the improvement of the strength quickly at the early period. At the later period, the carbonation reaction lasted for a long time with its physical properties remained stable. The results of SEM pictures revealed the existence of calcium deposition between the soil particles as the binders and the EDS analysis showed that the content of calcium element and carbon element grew with the increase of the content of calcined ginger nuts. The results in this research prove preliminarily that soil from the earthen sites modified with the calcined ginger nuts is suitable for grouting the fissures in earthen sites.