微生物诱导碳酸钙修复汉白玉石梁裂缝试验研究

石质文物劣化后产生裂缝等病害,需要恰当的修复方法。本研究应用微生物诱导碳酸钙沉积技术修复汉白玉石梁裂缝,模拟石质文物裂缝修复。研究对象为带V型槽的非贯通和贯通裂缝的汉白玉石梁(尺寸为40 mm×40 mm×160 mm),修复方法为先注浆后自由下渗。通过对比石梁修复前后破坏荷载和强度的变化以及CT扫描技术可视化非贯通裂缝修复过程来评价修复效果。结果显示:修复后石梁裂缝表面致密光滑,颜色与母材相近,整体美观性好;非贯通裂缝修复后破坏荷载均有所增加,贯通裂缝修复后的抗折强度能恢复到原有强度的35.12%,均值为3.684 MPa,最高能达到5.234 MPa;CT扫描结果定性和定量均表明胶凝体密度随修复进行而增加,接触面修复质量弱于其他位置。

Experiment research on the restoration of white marble beams using microbially-induced carbonate precipitation

Stone relics suffering from diseases such as cracks due to deterioration, need proper restoration methods. In our work, in order to simulate the restoration of cracks in stone relics, the technology of microbially-induced carbonate precipitation was applied to the restoration of broken marble beams. The research objects were some white marble beam models (40 mm × 40 mm × 160 mm) with V-shaped cracks, some of which penetrated the beam completely and some that did not. The restoration method was grouting and free infiltration. The effect of restoration was evaluated by comparing the change of load capacity and flexural strength before and after the restoration and by visualizing the restoration process of through cracks using computed tomography (CT) scanning. The results show that after restoration, 1) the surfaces of the cracks are dense and smooth, the color is similar to that of the base material and that the overall appearance is nice; 2) the load capacities of beams with non-through cracks were all increased, and the flexural strengths of the beams with through cracks reached a mean value of 3.684 MPa (recovering up to 35.12% of the original strength) and the maximum value of 5.234 MPa. The qualitative and quantitative results of CT scanning also indicate that the density of bio-cementation increases as the restoration goes on, and that the restoration quality of contact surfaces is weaker than that of other locations.