Drying Shrinkage of Heat-Cured Fly Ash-Based Geopolymer Concrete

Abstract

Fly ash-based geopolymer concrete is manufactured without using portland cement at all. This type of concrete has environmental benefit as it has very low greenhouse gas emission compared to that resulted from the production of portland cement. In addition, it also utilizes waste or by-product material that makes it more environmentally friendly. This paper presents the study of drying shrinkage of heat-cured fly ash-based geopolymer concrete. Geopolymer concrete in this study used low-calcium fly ash as its source material, alkaline solution and aggregates normally used for ordinary portland cement concrete. Four series of test specimens with different compressive strength were prepared to study the drying shrinkage of this concrete. The test results were then compared with the calculated results of drying shrinkage as predicted by Gilbert Method which is normally used for ordinary portland cement concrete. Test results show that the heat-cured fly ash-based geopolymer concrete undergoes very low drying shrinkage. The drying shrinkage strain at one year as calculated using Gilbert Method is much higher, about five to seven times, compared to the measured drying shrinkage strain from the tests.

Durability of mortar and concrete containing alkali-activated binder with pozzolans: A review

“…Miranda et al [22] Corrosion resistance NaOH and Na 2 SiO 3 FA Palacios and Puertas [23] Carbonation NaOH and Na 2 SiO 3 GBFS Fernandez-Jimenez et al [24] Acid attack and sulphate resistance NaOH and Na 2 SiO 3 FA Al-Otaibi [25] Chloride penetration resistance, porosity, carbonation Ca(OH) 2 and Na 2 SiO 3 GBFS Thokchom et al [26] Acid attack NaOH and Na 2 SiO 3 FA Wallah [27] Drying shrinkage NaOH and Na 2 SiO 3 FA Bernal et al [28] Carbonation and sorptivity NaOH and Na 2 SiO 3 GBFS and MK Allahverdi et al [29] Drying shrinkage NaOH and Na 2 SiO 3 GBFS Wongpa et al [30] Water permeability NaOH and Na 2 SiO 3 RHA and FA Yang et al [31] Shrinkage strain Ca(OH) 2 and Na 2 SiO 3 GBFS El-Sayed et al [7] Sulphate resistance NaOH and Na 2 SiO 3 GBFS Kushal and Partha [32] Porosity, water absorption and sorptivity NaOH and Na 2 SiO 3 FA Al Bakri et al [33] Acid resistance NaOH and Na 2 SiO 3 FA Chaparro et al [34] Corrosion resistance NaOH and Na 2 SiO 3 GBFS Beemamol et al [35] Chloride permeability and shrinkage NaOH FA Bernal et al [36] Carbonation NaOH and Na 2 SiO 3 GBFS and FA Prabu et al [37] Acid resistance, sulphate attack and chloride penetration NaOH, KOH, K 2 SiO 3 and Na 2 SiO 3 RHA and FA Shaikh [38] Chloride penetration, sorptivity and corrosion resistance NaOH and Na 2 SiO 3 FA Karim et al [39] Porosity, water absorption and thermal resistance NaOH GBFS, POFA and RHA FA: fly ash; GBFS: granulated blast furnace slag; MK: metakaolin; RHA: rice husk ash; POFA: palm oil fuel ash.…”

“…They concluded that the mortar specimens activated by NaOH and Na 2 SiO 3 is highly resistant to both H 2 SO 4 and HNO 3 . Wallah [27] made FA based NaOH and Na 2 SiO 3 activated concrete to observe drying shrinkage. Lower values of drying shrinkage were observed for heat-cured FA based activated concrete in which the entire test results were evaluated by Gilbert Method (usually utilized for OPC concrete).…”

Static and dynamic mechanical properties of high early strength alkali activated slag concrete

“…Reaction rate at the first stage is fast because of high pH value, high concentration of silicon ions and high temperature. So the initial fluidity of mixture will totally lose in a short time [17,42] . AAS binder can not fully merge with aggregate, a mass of pores will remain in the transition zone [43] .…”

Milestones in the analysis of alkali-activated binders

“…Since that time, there have been a number of studies of the engineering properties of concrete specimens (reinforced or unreinforced) based on solely fly ash-derived binders, including [48][49][50][51][52][53]. However, studies of durability-related properties such as [54,55] have highlighted the likely importance of inclusion of a calcium source in the mix designs as a way to control porosity and pore structure, and these more calcium-rich mixes currently appear to be the more likely way forward for applications in reinforced concretes [1].…”