Strength Characteristics of Open Air Cured Geopolymer Concrete

Alkali-activated concretes based on fly ash and blast furnace slag: Compressive strength, water absorption and chloride permeability

“…This behaviour of the FA/GBFS 80/20 concrete, which was not appreciable in samples with 100% FA (Valencia-Saavedra, Mejia de Gutiérrez and Gordillo, 2018), can be attributed to the presence of the blast furnace slag, a material that provides calcium to the system, generating hydrated calcium silicate gel as reaction product, in addition to the aluminosilicate gels proper to the alkaline activation of fly ash (C-A-S-H/N-A-S-H). This performance agrees with those reported by other authors (Manjunatha et al, 2014;Gopalakrishnan and Chinnaraju, 2019;Nath and Kumar, 2014). At 7 and 28 days for FA/GBFS concretes (80/20) designed with 400 kg/m 3 of precursor, Nath and Kumar (2014) reported compressive strength values similar to those obtained in the present study, although the proportions of activator and the characteristics of fly ash were different.…”

“…Aluminosilicate precursors with high calcium content are associated with the formation of an Al-substituted C-S-H (C-(A)-S-H) gel, while the reaction product of a precursor with low calcium content is a N-A-S-H gel (Na 2 O-Al 2 O 3 -SiO 2 -H 2 O) with a three-dimensional structure. Manjunatha, Radhakrishna, Venugopal, and Maruthi (2014), studied the mechanical behavior of FA/GBFS-based alkaliactivated concretes cured at room temperature. The authors reported superior mechanical properties compared to OPCbased concrete.…”

Effects of slag content on the residual mechanical properties of ambient air-cured geopolymers exposed to elevated temperatures

“…The above CaO-rich source materials form calciumsilica-hydrate (C-S-H) gels in addition to sodiumaluminate-silicate-hydrate (N-A-S-H) geopolymer gels and form complex C-(N)-A-S-H geopolymer gels which help to set and harden concrete at ambient temperatures. A number of studies have evaluated the mechanical properties of ambient air-cured fly ash geopolymers [2][3][4][5][6]. All the studies observed that the compressive strength of ambient air-cured fly ash geopolymers increases with increases in the slag contents [3][4][5][6], due to increased formation of C-(N)-A-S-H gels resulting from the slag contents.…”

Zero Cement Concrete with Self-Curing Technology: An Overview

“…Geopolymer concretes exhibited higher flexural strength than OPC concrete of similar compressive strength (Pradip Nath et al,). It has been found that the bond strength between geopolymer concrete and rebar is more than that of conventional concrete (G. S. Manjunatha, et al, 2014).Ordinary Concrete beam has higher flexural strength than geopolymer concrete beams. This result is little bit different from author expectation, geopolymer beams expected to higher flexural strength than ordinary concrete due to its high compressive strength.…”