Alkali activated cement mixture at ambient curing: Strength, workability, and setting time

Abstract

The success of ordinary Portland cement (OPC) comes at a risk to the environment because of the large carbon dioxide emissions associated with cement manufacturing. This has led the scientific community to look for alternative cementitious materials with lower environmental impact. Alkali activated cement (AAC) is an excellent alternative to this end. In this study, the effect of binder content, alkaline solid to binder ratio (AS/B), sodium silicate to sodium hydroxide solids ratio (SS/SH), and total water content to total solid binder ratio (TW/TB) on the strength, setting time and flowability of ambient cured AAC mixtures are studied using Taguchi method of experimental design. Binder content was varied from 550 to 750 kg/m 3 , AS/B ratio from 0.14 to 0.22, SS/SH ratio from 1.5 to 2.5, and TW/TB ratio from 0.29 to 0.39. The study results showed that within the investigated range, an increase in binder content has a minor effect on strength but resulted in a considerable increase in setting time and flowability. An increase in the AS/B ratio resulted in increased flowability and setting time and a decrease in strength. Moreover, the study also investigated the relationship between compressive strength and flexural strength.

Freeze–thaw resistance and sorptivity of fine‐grained alkali‐activated cement concrete

“…This is an important finding showing that a limit is required on the amount of alkaline content in the mixture for optimum mechanical and durability behaviors. Tekle et al 26 studied 0.14, 0.18, and 0.22 AS/B ratios. The maximum 28‐day compressive strength was obtained at 0.18.…”

“…An increase in AS/B (FGAAC-AS/B) decreased the compressive strength, while an increase in the SS/SH ratio (FGAAC-SS/SH) increased the strength. Further details regarding the effect of each of the parameters on the compressive strength can be found in Tekle et al 20,26…”

The effect of reinforcement ratio on the flexural performance of alkali-activated fly ash-based geopolymer concrete beam

“…An exponential urbanization and infrastructure development have created a vital need for a sustainable construction material with lower carbon dioxide (CO 2 ) emission [ 1 , 2 ]. Researches confirmed that there is about one kilogram of carbon dioxide emission per one kilogram production of Ordinary Portland Cement (OPC) [ 3 , 4 , 5 , 6 ]. Thus, the construction industry is a major source of greenhouse gas emissions.…”

Influence of fiber characteristics on sulfate resistance of ambient‐cured geopolymer concrete

“…28,29 Due to the economic and environmental concerns mentioned above, production of sustainable alternative binders to PC has gained considerable attention. 4,30,31 Geopolymers, also called alkali activated binders, are new generation binder types that stand out among the searches for green alternatives binders. 7,9,32,33 Geopolymer binders are semi crystal inorganic polymers synthesized by geopolymerization reactions between highly alkaline solutions (sodium hydroxide and sodium silicate) and aluminosilicate precursors (natural or waste pozzolans).…”

“…Due to the economic and environmental concerns mentioned above, production of sustainable alternative binders to PC has gained considerable attention 4,30,31 . Geopolymers, also called alkali activated binders, are new generation binder types that stand out among the searches for green alternatives binders 7,9,32,33 .…”