Quantitative Effects of Mixture Parameters on Alkali-Activated Binder-Based Ultra-High Strength Concrete at Ambient and Elevated Temperatures

Abstract

This work investigates the effects of mixture parameters on the slump flow and compressive strength of a new type of alkali-activated binder-based ultra-high strength concrete (AAB-UHSC) before and after exposure to high temperatures. The innovative UHSC adopts a combination of sodium silicate (SS) and potassium carbonate (PC) as the activator. Compared with the alkali hydroxide that is currently used in existing AAB-UHSC, alkali carbonate salts are environmental-and user-friendly and cost-effective. Four mixture proportioning parameters, including water/precursor ratio, activator/precursor ratio, silica fume (SF) replacement percentage, and SS/PC ratio, are evaluated regarding their quantitative effects on fresh and hardened properties of AAB-UHSC using Taguchi method. The analysis of variance (ANOVA) reveals that the activator/precursor ratio is the decisive parameter controlling the slump flow diameter of fresh AAB-UHSC, whereas all four parameters have considerable influence on compressive strength of AAB-UHSC at room temperature. Although increasing the activator/precursor ratio increases compressive strength of AAB-UHSC at room temperature, it is adverse for residual strength of AAB-UHSC after exposure to high temperatures. Based on the test results and ANOVA, a mixture proportioning method of AAB-UHSC, which is lacking in existing literatures, is proposed and experimentally validated.

Use of a Full Factorial Design to Study the Relationship between Water Absorption and Porosity of GP and BW Mortar Activated

“…Tus, it has been developed in a systematic way for all new products from the waste generated from all industrial and construction activities [2]. Alkali-activated benders are getting a lot of consideration because of their strong resistance, durability, and low environmental impact [3,4]. Recent studies have proven that the gases that cause global warming can be reduced by up to eighty percent by using alkaline concrete compared to Portland cement [5].…”

Phase Analysis of Alkali-Activated Slag Hybridized with Low-Calcium and High-Calcium Fly Ash

“…The alkaline activation of sole slag (i.e., without fly ash incorporation), FA-F, FA-C, or fly ash-slag blends as novel binders have gained significant attention recently since contemporary environmental concerns and economic realities demand these industrial byproducts be effectively re-utilized [4][5][6][7]. For instance, alkali-activated slag binders have demonstrated ultrahigh strength [8,9], antifire-induced explosive capacity [10,11], remarkable chloride durability [12,13] and sulfate attacks [14,15]. Alkali-activated FA-F binders are featured with outstanding acid resistance and thermal stability [16,17].…”