Effects of Alkaline Solution on Properties of the HCFA Geopolymer Mortars

Malkawi, Ahmad B.; Nuruddin, Muhd Fadhil; Fauzi, Amir; Al-Mattarneh, Hashem; Mohammed, Bashar S.

doi:10.1016/j.proeng.2016.06.581

Cited by 145 publications

(56 citation statements)

References 14 publications

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“…Figure 9. Major impacts plot for the compressive strength at 28 days of batch GP1 79 [19] 33-42 [21] 32 [22] 50 [23] 62 [24] 48.45 [25] 60-85 [26] As expected, for batch GP1, the increase of the water content was found to increase both the initial and the final setting time. This was expected as the polymerization process of geopolymer is a water producer process; thus, increasing the water enhances the backward reaction according to Le Chateliers principle.…”

Section: 1 2 Compression Strength After 28 Daysmentioning

confidence: 73%

Optimizing the Properties of Metakaolin-based (Na, K)-Geopolymer Using Taguchi Design Method

Al-Dujaili

Disher

Hassan

2020

IJE

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Geopolymer paste is an innovative construction material which shall be produced by chemical action of inorganic molecules. It is a more environmentally friendly alternative to conventional Portland cement which is abundantly available worldwide. In this study, the influence of different alkaline activators (Na and K) on the mechanical and thermal behaviors of metakaolin-based geopolymer was investigated. The aims of this study is to find out the mixes and their process parameters, which are appropriate to produce Geopolymer paste with one of the highest compressive strength, highest-lowest porosity and highestlowest initial and final setting time. Taguchi method is used in the design of the experiments for the metakaolin-based Geopolymer. Five factors were selected as process parameters that are more likely to affect the Geopolymer characteristics. These are the amount of Si, alkali type, alkali reagents ratio, mixing time, and water content. The effect of these parameters on the setting time, density, porosity, compressive strengths at 7 and 28 days. The results of study found that the Geopolymer paste with high compressive strength of (107.2MPa) can be obtained with the formula (0.2K2O.0.8Na2O. Al2O3. 3.6SiO2.xH2O) using proper processing condition in which the alkali silicates to the alkali hydroxides molar ratio should be kept in the range of 2.26. The results revealed that the use of alkali solution of Kions and Na-ions improves the compressive strength of the geopolymer remarkably as compared with the use of Na-ions solution along. In addition, it has been noticed that the setting time is reduced, for geopolymers with silica content of less than 3.8, when K-ions is used. Similarly, the bulk density of geopolymers is found to be reduced by adding K-ions.

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Section: 1 2 Compression Strength After 28 Daysmentioning

confidence: 73%

Optimizing the Properties of Metakaolin-based (Na, K)-Geopolymer Using Taguchi Design Method

Al-Dujaili

Disher

Hassan

2020

IJE

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“…The Na/Al ratio is found to be increasingly high at relatively higher activator content, resulting in excess concentration of Na+ in paste systems. The excess sodium oxide in the mix combines with water to produce more hydroxyl ions in the geopolymer paste which later reacts with calcium to form calcium hydroxide and thus decreases its strength [47]. Similarly, the surplus amount of Na + ions in the mix reacts with CO 2 in the surrounding area to form a white precipitate on the surface of the specimens, which significantly contributed to the lower strength evolution at higher H 2 O/Na 2 O proportions, particularly at ambient temperature.…”

Section: Resultsmentioning

confidence: 99%

Mechanical and microstructural properties of high calcium fly ash one-part geopolymer cement made with granular activator

Mohammed

Haruna

Wahab

et al. 2019

Heliyon

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In this present experimental study, geopolymer cement is developed using high calcium fly ash and used in the production of one-part alkali-activated binders. At 8–16 percent of the total precursor materials, the HCFA was activated with anhydrous sodium metasilicate powder and cured in ambient condition. Five mixtures of one-part geopolymer paste were intended at a steady w/b proportion. Density, flowability, setting time, compressive strength, splitting tensile strength and molar ratio impact were envisaged. It was observed that the setting time of the designed one-part geopolymer paste decreases with higher activator content. The experimental findings showed that the resistance of one-part geopolymer cement paste increases with comparatively greater activator content. However, raising the granular activator beyond 12 percent by fly ash weight decreases the strength and workability of the established one-part geopolymer cement. The optimum mix by weight of the fly ash was discovered to be 12 percent (i.e. 6 percent Na2O). At 28 days of curing, one-part alkali-activated paste recorded the greatest compressive strength of almost 50 MPa. The density of the one-part geopolymer paste is nearly the same regardless of the mixes. Microstructural assessment by FESEM, FTIR and XRD has shown that the established geopolymer paste includes quartz, pyrrhotite, aluminosilicate sodium and hydrate gels of calcium aluminosilicate. Based on the experimental information acquired, it can be deduced that the strength growth of one-part geopolymer cement is similar to that of Portland cement.

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“…(SPCI), in Malaysia, with the chemical composition of SiO 2 = 30.1%, Na 2 O = 9.4% and water (H 2 O) 60.5% by mass. The mass ratio binder-to-liquid (alkali activator) of all mixes was kept at 2.0, which was suggested based on previous work [12,17,18]. In this investigative study, a geopolymer mix was prepared in which the binder consists of high calcium fly ash.…”

Section: Introductionmentioning

confidence: 99%

Bonding Strength Characteristics of FA-Based Geopolymer Paste as a Repair Material When Applied on OPC Substrate

et al. 2020

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This investigative study aims to study the mechanical and morphological properties of fly ash (FA)-based geopolymer paste as a repair material when applied on ordinary Portland cement (OPC) overlay concrete. The first part of this study investigates the optimal mix design of FA-based geopolymer paste with various NaOH concentrations of 8, 10, 12, and 14 M, which were used later as a repair material. The second part studies the bonding strength using a slant shear test between the geopolymer repair material and OPC substrate concrete. The results showed that a shorter setting time corresponds to the higher NaOH molarity, within the range of 53 and 30 min at 8 and 14 M, respectively. The compressive strength of FA-based geopolymer paste was found to reach 92.5 MPa at 60 days. Also, from the slant shear test results, prism specimens with 125 mm length and 50 mm wide have a large bond strength of 11 MPa at 12 M. The scanning electron microscopy/energy-dispersive X-ray (SEM/EDX) analysis showed that the OPC substrate has a significant effect on slant shear bond strength, where the presence of free cations of Ca2+ on the OPC substrate surface contributed to the formation of calcium alumina-silicate hydrate gel (C-A-S-H) by building various cross-links of Ca-O-Si.

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Effects of Alkaline Solution on Properties of the HCFA Geopolymer Mortars

Cited by 145 publications

References 14 publications

Optimizing the Properties of Metakaolin-based (Na, K)-Geopolymer Using Taguchi Design Method

Optimizing the Properties of Metakaolin-based (Na, K)-Geopolymer Using Taguchi Design Method

Mechanical and microstructural properties of high calcium fly ash one-part geopolymer cement made with granular activator

Bonding Strength Characteristics of FA-Based Geopolymer Paste as a Repair Material When Applied on OPC Substrate

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