Development and Performance Evaluation of Very High Early Strength Geopolymer for Rapid Road Repair

Advances in Materials Science and Engineering

Phiangphimai

Damrongwiriyanupap

et al. 2018

is research focuses on developing a mix design methodology for alkali-activated high-calcium fly ash concrete (AAHFAC). High-calcium fly ash (FA) from the Mae Moh power plant in northern ailand was used as a starting material. Sodium hydroxide and sodium silicate were used as alkaline activator solutions (AAS). Many parameters, namely, NaOH concentration, alkaline activator solution-to-fly ash (AAS/FA) ratio, and coarse aggregate size, were investigated. e 28-day compressive strength was tested to validate the mix design proposed. e mix design methodology of the proposed AAHFAC mixes was given step by step, and it was modified from ACI standards. Test results showed that the 28-day compressive strength of 15-35 MPa was obtained. After modifying mix design of the AAHFAC mixes by updating the AAS/FA ratio from laboratory experiments, it was found that they met the strength requirement.

Section: Resultsmentioning

confidence: 99%

A Mix Design Procedure for Alkali‐Activated High‐Calcium Fly Ash Concrete Cured at Ambient Temperature

Advances in Materials Science and Engineering

Phiangphimai

Damrongwiriyanupap

et al. 2018

“…In addition, ratio of sand to binder is one of the important factor for considering as repair materials which related to a homogeneous matrix of geopolymer binder as reported by Thakur and Ghosh [14]. In order to utilize geopolymer binder as an alternative repair material, many researchers [2,3,[15][16][17][18][19] have studied the setting time, strength development and bonding strength for proving their properties compared with commercial repair materials in the market. As mentioned, the 7-day strength requirement of rapid hardening cementitious materials was 28.0 MPa as per ASTM C928-13 [20], and the initial setting time and minimum strength requirements for repair binder were 30 minutes and 35.0 MPa, respectively, as per ASTM C881/C881M-14 [21].…”

Section: +mentioning

confidence: 99%

Shear Bond Strength of Fa-Pc Geopoylmer Under Different Sand to Binder Ratios and Sodium Hydroxide Concentrations

Hanjitsuwan

Detphan

et al. 2018

GEOMATE

This paper presents the effects of sand to binder (S/B) ratio and sodium hydroxide (NaOH) concentration on setting time, compressive strength, and shear bond strength of fly ash (FA)-Portland cement (PC) geopolymer binder. Geopolymer binder is manufactured from FA and PC at the ratio of 90:10 by weight of binder. The liquid alkali solution used in this study are sodium hydroxide (NaOH) and sodium silicate (Na2SiO3) solutions. The Na2SiO3/NaOH ratio of 2.0, liquid alkali solution/binder ratio of 0.60, and curing at ambient temperature are fixed in all mixes. The differences in NaOH concentrations of 5, 10 and 15M and S/B ratios of 1.00, 1.25 and 1.50 has been investigated. Test results show that the differences of NaOH concentration and S/B ratio has an effect on setting time, compressive strength and shear bond strength of FA-PC geopolymer mortar. The setting time of mortars are obviously decreased with increasing of S/B ratio whereas the setting time of mortars are obviously increased with increasing of NaOH concentration. The compressive and shear bond strengths of mortars increase as increasing of both S/B ratio and NaOH concentration up to a threshold limit. The highest slant shear strength between Portland cement concrete substrate and FA-PC geopolymer mortar is found in the mortar with 1.25 S/B ratio and 10M NaOH concentration which gives 24.1 MPa.

“…Moreover, alkali-activated binders have also been used as pavement repair materials (Hawa et al, 2013;Alanazi et al, 2016;Duan et al, 2016a). For the use of alkali-activated binders as repair and reinforcement of damaged notched concrete beam, Phoo-ngernkham et al (2016b) reported that the flexural strength of notched concrete beam filled with the alkali-activated binder made from low calcium fly ash plus granulated blast furnace slag activated with alkali solutions was similar to most commercial repair materials.…”

Section: Introductionmentioning

confidence: 99%

Adhesion characterisation of Portland cement concrete and alkali-activated binders

Advances in Cement Research

Hanjitsuwan

et al. 2019

In this paper, alkali-activated binders (AAB) are investigated for their potential use as repair materials of Portland cement concrete (PCC). The adhesion characterization of PCC and repair materials using AAB made from fly ash (FA) and Portland cement (PC) activated with sodium hydroxide and sodium silicate solutions, AAB made from FA and calcium hydroxide (CH) activated with sodium hydroxide and sodium silicate solutions, and commercial repair material (RMs) have been investigated. Test results show that the AAB 2 with additives gives high bond strength which is similar to the use of RMs. Bond strength between PCC substrate and AAB with additives are improved, due to increased reaction products especially C-S-H gel. However, the CH replacement at 15% shows a large amount of calcite resulting in reduction in bond strength. The failure patterns and fracture interface images of the tested specimens also demonstrate the quality of the developed bond strength. It was shown that the interface zone of PCC substrate and AAB is homogeneous with no visible gap between the two bonding surfaces. It is suggested that the AAB with PC as additive can be used as a repair binding material which not only has high bond strength but also is cost-effective.