不同类型减水剂对渣土基高流态回填材料性能的影响

相比传统回填材料,渣土基高流态回填材料具有高流态、自流平、自密实等优点,能够有效避免因压实不充分导致的工程问题。然而,渣土基高流态回填材料在使用中存在易沉陷、易泌水等问题,限制了其工程化应用空间。在本文中,选择了聚羧酸减水剂(PCE)、脂肪族减水剂(SAF)、萘系减水剂(FDN)、三聚氰胺减水剂(PMS)四种减水剂来调节渣土基高流态回填材料的用水量和流动度,同时比较了四种减水剂对渣土基高流态回填材料性能的影响。结果表明:在保持相同流动度下,四种减水剂的减水效果从高到低依次为PCE＞SAF＞PMS＞FDN;在经时流动度方面,FDN体系较其他减水剂体系在1 h内具有更好的流动性,四种减水剂体系的流动度保持性从优到劣依次为FDN＞PCE＞PMS＞SAF;四种减水剂均能降低渣土基高流态回填材料的泌水率,缩短渣土基高流态回填材料的凝结时间。

Effect of Plasticizer Type on Properties of Construction Spoil Based High-Fluid Backfill Materials

Construction spoil based high-fluid backfill material has the advantages of high fluidity, self-leveling, self-compaction and so on. Compared with the traditional backfill materials, it can effectively avoid the engineering problems caused by insufficient compaction. However, construction spoil based high-fluid backfill material is easy to settle and bleeding, which limits its engineering application. In this paper, polycarboxylate superplasticizer (PCE), sulfonated acetone formaldehyde (SAF), naphthalene superplasticizer (FDN) and melamine superplasticizer (PMS) were used to reduce water consumption and optimize fluidity. Meanwhile, the effects of four plasticizers on the properties of construction spoil based high-fluid backfill materials were compared. The results indicate that under the same fluidity, the water reducing effect of four plasticizers decreases in order: PCE>SAF>PMS>FDN. In terms of temporal fluidity, FDN system has better fluidity within 1 h than other plasticizer systems. The fluidity retention of four plasticizers systems decreases in order: FDN>PCE>PMS>SAF. Four plasticizers significantly reduce the bleeding rate of construction spoil based high-fluid backfill materials and shorten the setting time.