Optimization of Ambient-Cured, Alkali-Activated One-Part Green Mortar with Industrial Waste Using the Taguchi & Taguchi- Grey relational Method

This study develops a novel one-part alkali-activated mortar (AAOPM) synthesized at room temperature, incorporating nano-silica, using industrial waste-fly ash (FA) and ground granulated blast-furnace slag (GGBFS) as precursors, and anhydrous sodium metasilicate (Na₂SiO₃) as the solid activator. Unlike conventional two-part systems reliant on liquid alkalis, this ready-to-use formulation improves on-site practicality and safety. Optimal mix designs were derived via Taguchi combined with Taguchi-Grey Relational Analysis (TGRA) using an L₉ orthogonal array. Four factors at three levels were assessed: FA/GGBFS ratio (F/S 1–2.33), water/binder ratio(W/B 0.4–0.5), activator dosage(SMS 8–12%), and nano-silica content(NS 1–2%). Multi-response outputs comprised fresh properties(flow, setting time) and mechanical properties(compressive, flexural strength at 28 days), which were analysed using Minitab software. The significance of the factors was confirmed through analysis of variance, and the strongest effects of the factors were demonstrated on strength responses by NS content and the F/S ratio, and flow and setting time by W/B. TGRA validation determined the best conditions (F/S 1:1, W/B 0.5, 8% activator, 2% NS) with a compressive strength of 50 MPa and flexural strength of 6.5 MPa far greater than most reported AAOPMs. Microstructural studies demonstrated thick C/N-(A)-S-H gels, compact morphology, and high thermal stability characterization.本研究开发了一种新型室温合成的单组分碱激发砂浆（one-part alkali-activated mortar, AAOPM），以工业废料粉煤灰（fly ash, FA）和粒化高炉矿渣粉（ground granulated blast-furnace slag, GGBFS）为前驱体，掺入纳米二氧化硅，并以无水偏硅酸钠（Na₂SiO₃）作为固体激发剂。与传统依赖液态碱的双组分体系不同，该即用型配方提升了现场实用性与施工安全性。研究通过田口方法结合田口-灰色关联分析（Taguchi-Grey Relational Analysis, TGRA）并采用L9正交表，推导得到最优配合比设计。本次研究考察了4个因素各3个水平：粉煤灰/粒化高炉矿渣粉掺量比（F/S 1~2.33）、水胶比（W/B 0.4~0.5）、激发剂掺量（SMS 8%~12%）以及纳米二氧化硅掺量（NS 1%~2%）。多响应性能指标涵盖新拌性能（流动度、凝结时间）与力学性能（28天抗压强度、抗折强度），并借助Minitab软件开展分析。通过方差分析验证了各因素的显著性，结果表明：纳米二氧化硅掺量与粉煤灰/粒化高炉矿渣粉掺量比对强度响应的影响最为显著，而水胶比对流动度与凝结时间的影响最强。经田口-灰色关联分析验证，最优制备条件为F/S=1:1、W/B=0.5、激发剂掺量8%、纳米二氧化硅掺量2%，其抗压强度达50 MPa，抗折强度达6.5 MPa，远优于多数已报道的单组分碱激发砂浆。微观结构研究显示，该体系形成了致密的C/N-(A)-S-H凝胶结构，形貌紧凑且具备优异的热稳定特性。