咖啡渣矿渣地聚合物固化软土的力学性能研究

The mechanical properties of coffee grounds-slag based geopolymers stabilized soil

为降低造价和碳排放量,通过研究地聚合反应结合有机质废弃物咖啡渣和工业废弃物矿渣制成软土固化剂的可能性,改良地聚合物水泥的性能,并对其效果进行评估。实验以废弃咖啡渣、矿渣为原料,氢氧化钠作为碱性激发剂,制备咖啡渣-矿渣基地聚合物用于软土加固。研究不同咖啡渣掺量、水灰比和养护时间对固化软土的抗压强度和抗劈裂强度等力学性能影响。结果表明:在室温条件下使用30%固化剂掺量时,在矿渣基地聚合物固化剂中将5%矿渣用咖啡渣替代矿渣并采用0.6水灰比时,所得到的固化软土力学性能最优,28天无侧限抗压强度和抗劈裂强度分别为达到1.7 MPa和318.3 kPa。该软土固化剂强度优于水泥,在满足实际工程要求的同时,最大化利用了各类废弃物。

In order to reduce the cost and carbon emissions, the possibility of combining a highly organic waste coffee ground(CG) with industrial waste slag(S) into a sustainable construction material is evaluated by a geopolymerization process and assess its performance. A new type of geopolymeric material, which is used to stabilize soils, is synthesized using wasted coffee grounds and blast furnace slag as the base material, and sodium hydroxide solution(NAOH) as the alkaline liquid activator. The mechanical properties of coffee grounds-slag based geopolymers stabilized soil is discussed in detail from unconfined compressive strength(UCS) test and splitting tensile strength(STS) test. It is found that when the 5% of slag is replaced with coffee grounds at a water-cement ratio of 0.6 and cured at 21 ℃ for 28 days, the stabilized soil shows optimal mechanical properties with a relatively high UCS of up to 1.7 MPa and a STS of up to 318.3 kPa This geopolymer cement is better than portland cement and it maximizes the use of wasted materials while meeting actual engineering requirements.