矿渣粉掺量及养护条件对地聚合物混凝土的影响

以粉煤灰和矿渣粉为原材料制备地聚合物混凝土,研究矿渣粉掺量和不同配比碱激发剂对于地聚合物混凝土坍落度、凝结时间及抗压强度的影响;并且通过3种不同的养护方式,探究养护温度及湿度对于地聚合物混凝土表观性状和力学性能的影响。研究结果表明：随矿渣粉掺量的提高,地聚合物混凝土强度增加,而凝结时间大幅度缩短;提高碱激发剂中水玻璃的掺量将降低混凝土的坍落度和凝结时间,而抗压强度呈先增大后减小的趋势;提高养护的湿度可有效地抑制地聚合物的泛碱现象,并取得较高的后期强度;提高养护温度可使地聚合物取得较高的早期强度,但后期强度增长缓慢。研究表明当矿渣粉掺量为胶材的30%,碱激发剂中水玻璃与氢氧化钠溶液的比值为1.5：1时,可制备在常温下即可硬化并取得较高强度的地聚合物混凝土。

The Effects of Slag Content and Different Curing Conditions on Geopolymer Concrete

In this paper, fly ash and slag were used as precursors to prepare geopolymer concrete. The influence of slag content and different proportioning of alkali activator on workability, setting time and mechanical properties of geopolymer concrete were investigated. Through different ways of curing, the influence of curing temperature and humidity on the strength development and mechanical properties of geopolymer concrete were studied. The results show that the compressive strength of geopolymer concrete increases with the increase of slag content, while the setting time shortens substantially with the increase of slag content; the increase of sodium silicate content in alkali activator leads to reduction of the slump, setting time, but the compressive strength increase first and then decrease; high curing humidity helps to prevent the crystalline bloom of the concrete, and achieve higher later strength; the early strength of geopolymer can be greatly improved with high temperature curing, but the later strength will hardly increase. The results show that when the slag content is 30% of the cementitious material and the ratio of water glass to sodium hydroxide solution is 1.5:1, geopolymer concrete with high strength could be prepared at ambient temperature.