花岗岩锯泥对混凝土耐久性影响的研究

Study on the Influence of Granite Sawdust for the Durability of Concrete

摘要: 花岗岩锯泥为花岗岩石材切割、抛光等加工过程中产生的废弃物，含水率高，难以大量应用。本试验研究了不同等级混凝土中掺入100 kg/m3的湿花岗岩锯泥，等量取代粉煤灰和细砂颗粒，研究湿花岗岩锯泥对混凝土工作性能、力学性能以及耐久性的影响规律。研究表明湿锯泥的掺入对不同标号混凝土拌合物工作性能、力学性能均无不利影响，但是会降低混凝土氯离子扩散系数并减少干燥收缩，有利于提高混凝土的耐久性。这主要是因为锯泥粉体的活性低，掺入后会增加混凝土小于20 nm的无害孔的含量，同时锯泥比粉煤灰的粒径更小，具有更好的填充效果，从而明显降低大于200 nm有害孔的含量，有助于耐久性的提升。同时锯泥对混凝土水化产物无明显影响。

Abstract: Granite saw mud is the waste generated in the processes of cutting and polishing granite stone. It is difficult to be widely used for its high water content. In this experiment, wet granite saw mud with a dosage of 100 kg/m3 is added to concrete to replace fly ash and fine sand particles. The influence of wet granite saw mud on the workability, mechanical properties and durability of concrete is studied. The results show that the addition of wet sawdust has no adverse influence on the workability and mechanical properties of concrete. In addition, it reduces the chloride ion diffusion coefficient and the drying shrinkage of concrete, which is conducive to improving the durability of concrete. This is mainly because of the low activity of the sawdust powder, which will increase the content of harmless pores to less than 20 nm in the concrete after mixing. And the particle size of sawdust is smaller than the fly ash, which has a better filling effect. Thus, significantly reducing the content of harmful pores greater than 200 nm, which is conducive to improving the durability of concrete. At the same time, granite saw mud has no obvious effect on the hydration products.