掺纳米SiO_2粉煤灰夹芯砌块的抗折强度

Bending Strength of the Nano-silica Doped Flyash Sandwich Block

利用纳米SiO2、水泥、粉煤灰等主要原材料,加入适量外加剂,制作空心砌块,中间填入废弃聚苯乙烯塑料泡沫,通过自然养护方法研制出一种符合节能要求的自保温墙体材料——掺纳米SiO2粉煤灰夹芯砌块。以普通粉煤灰混凝土空心砌块规格和块型的设计要求和标准作为本研究砌块设计方案的基础,设计出尺寸、孔洞大小及孔洞分布符合要求的砌块。研究了粉煤灰、纳米SiO2、水泥及水等影响砌块强度的主要因素,以砌块抗折强度为主要指标,取4因素、3水平进行正交试验,优化砌块配合比参数,最终得出最佳配比为粉煤灰40%,水泥14%,纳米SiO2 0.5%,水掺量为22%,该砌块具有较高的抗折强度及较低的成本。该配合比的因素水平组合与前期研究中取得较高抗压强度的因素水平一致,并且其抗折强度与抗压强度比值较高;该配合比砌块不仅抗压强度高,而且抗折强度大,应用该砌块砌筑的砌体具有较高承受复杂应力的能力。

In this paper, a new self thermal insulation mural material is proposed. Its major components include nanometer SiO2, portland cement and fly ash. It is made by mixing shrinkage-reducing agent, filling waste polystyrene in the hole, and natural curing. It is called the nano-silica doped flyash sandwich block. Based on the design requirements and standards of ordinary fly ash concrete hollow block, the corresponding size of the block, the size and distribution of the holes for this material are determined. The influences of major-factors such as fly ash, nanometer material, portland cement and water on the strength of the block are studied. The bending strength is the most important. Four factors and three levels for the orthogonal experiment are selected to optimize the matching ratio of the block. The result is 40% of fly ash, 14% of the portland cement, 0.5% of nanometer SiO2 and 22% of the water ash ratio. Such block features high bending strength and low cost. The bending strength and the compressive strength reach the same factor level combination as being reached in previous studies, but with higher ratio of bending strength to compressive strength. The block made by such matching ratio has a higher compressive strength and a higher flexural strength. The masonry made by such block can better withstand complex stresses.