中国传统糖水灰浆和蛋清灰浆科学性研究

Impacts of sugar and egg-white as additives on the performance of traditional lime mortar and their mechanisms

红糖灰浆和蛋清灰浆作为我国传统石灰浆,在岭南等地区具有广泛应用.本文以这两类灰浆为研究对象,通过实验室模拟样品的物理性能测试以及灰浆固化后的成分和结构分析,探讨糖和蛋清对灰浆性能的影响及作用机理.结果表明,蔗糖对石灰浆具有减水作用,2%的蔗糖含量减水效果就达到20%以上,能有效降低灰浆干缩开裂的风险.但是,蔗糖含量提高会影响灰浆的抗压强度和耐水性能.蛋清对石灰浆具有增稠、提高粘结性、自修复能力和减小开裂风险的作用,但是对灰浆的抗压强度和表面硬度有一定负面影响.主要原因是蛋清的加入使灰浆结构致密,减缓了碳化作用但它会在固化后的灰浆表面聚集,形成较多小孔,影响灰浆表面性能.建议这两类添加剂的使用量在4%以下.

The brown sugar and egg-white are wildly used as lime mortar additives in southeast of China and other regions. In this paper, the mechanical properties testing and the composition and structure after curing were used to discuss the impact of these two additives on the performance of lime mortar and their mechanism. The results indicate sugar could reduce the water-lime ratio of lime mortar. When 2% sugar was added the water reduce effect could reach above 20% and effectively reduce the risk of cracking induced by mortar dry shrinkage. However, the excessive sugar content would affect the compressive strength and water resistance of mortar. Egg-white could improve the consistence, cohesiveness, durability and reduce the risk of cracking of lime mortar, while it has negative influence on the compressive strength and surface hardness of lime mortar. The main reason is the addition of egg-white make the mortar become much more compact and slow down the carbonation progress of lime mortar. But the egg-white gather on the surface on the mortar would influence the surface properties of mortar. Thus we suggest that the safe amount of these two additives is less than 4%.