矿粉掺量对废弃超细砂制备砂混凝土密度及强度影响研究

以航道整治废弃超细砂为主要原料,通过振动成型制备砂混凝土(Sand Concrete).首先通过干拌振捣密实计算干拌物密度的方法研究矿粉掺量对砂混凝土干拌物密度的影响,然后以试件7 d、14 d和28 d抗压强度、劈裂抗拉强度和浸水抗压强度为控制标准,研究矿粉掺量对砂混凝土性能的影响,最后通过XRD对砂混凝土试件进行分析.试验结果表明:在水胶比为0.38,减水剂掺量为0.5%情况下,砂混凝土最佳配合比为废弃超细砂75.3%、水泥16.5%、矿粉8.2%.采用最佳配合比所制砂混凝土28 d抗压强度、劈裂抗拉强度和浸水抗压强度均达到最优, XRD分析表明所制砂混凝土含有大量水化硅酸钙(C-S-H)和钙矾石等水化产物.研究为航道整治废弃超细砂的开发利用提供一种技术途径,对于废弃超细砂资源丰富而普通混凝土砂石材料匮乏的地区具有显著的经济价值和广阔的应用前景.

Effect of Slag Content on Density and Strength of Sand Concrete Made by Waste Ultra-fine Sand

Waste ultra-fine sand from waterway regulation was used as main raw material to prepare sand concrete by vibrating forming.An initial study on the effect of slag content on the density of sand concrete dry mixture was conducted by optimizing the maximum packing mass volume of dry mixture,then 7 d,14 d and 28 d compressive strength,tensile strength and compressive strength after softening were tested to determine the influence of slag content on the performance of sand concrete.X-ray diffraction(XRD) technique was used to analyze sand concrete specimens.The result shows that the best mixing ratio of this sand concrete is 75.3% of waste ultra-fine sand,16.5% of cement,8.2% of slag with water/binder ratio of 0.38 and water reducing agent dosage of 0.5%.The optimal 28 d compressive strength, tensile strength and compressive strength after softening of the sand concrete can be achieved and the XRD pattern indicates that there are quite a lot of hydrate products such as calcium silicate hydrate(C-S-H) gel and ettringite in sand concrete specimens.For the areas with rich waste ultra-fine sand resources but lack of ordinary sand materials for concrete,the study provides a technical approach for the utilization of waste ultra-fine sand from waterway regulation, having significant economic value and broad application prospects.