Fly Ash Utilization in Grouting Applications

Pekrioglu, Ayse; Doven, Ata G.; Tumay, Mehmet T.

doi:10.1061/40663(2003)65

Cited by 7 publications

(3 citation statements)

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“…One of these researches has been recently published and it 87 deals with the optimization of both the w:c ratio and the binder design, by using silica fume 88 in order to modify the viscosity [18] and to improve the service behavior of cement grouts. 89With respect to fly ash, there are some studies that claim the feasibility of using fly ash in 90 structural fills, and other geotechnical applications [19, 20]. In view of that, as it has been 91 shown, up to our knowledge the performance of fly ash cements for micropiles grouts has not 92 been studied, especially with regard to their microstructure and durability, despite the fact 93 that there are many evidences that they could produce an improvement compared to ordinary 94 Portland cement.…”

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Microstructure and durability of fly ash cement grouts for micropiles

Pastor

Ortega

Flor

et al. 2016

Construction and Building Materials

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This paper presents a study on the possibility of using fly ash cement as grouts for micropiles. 19 This type of special geotechnical work is commonly used for many applications. Generally, 20 micropiles grouts are prepared using Portland cement, although the standards do not restrict 21 the cement type to use, as long as they achieve a strength requirement. In this research, fly 22 ash cement grouts made with w:c ratios 0.40, 0.45, 0.50 and 0.55 were studied from 2 up to 23 90 days of age. Their microstructure was characterized using the non-destructive impedance 24 spectroscopy technique, electrical resistivity, and mercury intrusion porosimetry. Their 25 2 durability properties have been studied by determining the water penetration under pressure, 26 and the chloride diffusion coefficient. The compressive strength was also measured and 27 determined, and a maximum water:cement ratio, different for each cement type was obtained. 28All the results were compared to those obtained for Portland cement grouts. The results 29 obtained confirm that the performance of micropiles made using fly ash cement grouts is 30 adequate, and as it is well know the cements with mineral admixtures provide environmental 31 benefits, so the use of cement including fly ash will contribute to the sustainability, with 32 similar properties to those given by OPC. 33Keywords: micropiles, special geotechnical works, fly ash, durability, microstructure, 34 impedance spectroscopy, water:cement ratio. 35 1.-INTRODUCTION 36In the field of geological engineering, the use of special geotechnical works has become very 37 important. Some of the most commonly used special geotechnical works for civil engineering 38 structures and for building foundations are piles, micropiles, soil anchors and jet grouting 39injections. There are great differences between those types of works and one of these 40 differences is related to the material in which the steel reinforcement elements are embedded. 41In the case of the piles, concrete is usually used. However, for micropiles, soil anchors and jet 42 grouting injections, the reinforcement elements are embedded in cement grouts, although 43 mortars might also be used. This fact is very important, because the behaviour of the cement 44 grouts and mortars shows many differences compared to concrete. For example, in general 45 the porosity of hardened grouts is greater than the porosity of concretes [1], [2], and it could 46 influence the durability and mechanical properties of the elements of each particular special 47 geotechnical work. But on the other hand, a higher amount of cement might improve the 48 durability of this type of elements. So, a different performance could be expected if the 49 material used to protect the reinforcement steel elements is cement grout or concrete, as it is 50 3 usual for the majority of civil engineering structures. Furthermore, the uncertainties can 51 increase as a function of the cement type used, especially if it is used a sustainable cement, 52 which incorporates som...

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Microstructure and durability of fly ash cement grouts for micropiles

Pastor

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Flor

et al. 2016

Construction and Building Materials

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“…Ma et al [11] conducted a study on the shear-thickening behavior of fly ash (FA), slag (SL), and limestone powder (LP) instead of cement slurry and explored the effect of the materials on the rheological curve parameters and shear-thickening effect. Zhang et al [12] comprehensively investigated the effect of the mineral admixture type and dosage on the rheological and mechanical behavior of a newly developed backfill material, cementitious foam backfill (CFB), with the selected variable materials being fly ash (FA), ground granulated blast furnace slag (GGBS), and quicklime. It can be found that the use of fly ash as a mineral admixture not only improves the grout performance substantially but also serves as an important component of backfill material cementitious foam [12], natural hydraulic lime-based mortar [13], clay-cement composite grout [14], etc.…”

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“…Zhang et al [12] comprehensively investigated the effect of the mineral admixture type and dosage on the rheological and mechanical behavior of a newly developed backfill material, cementitious foam backfill (CFB), with the selected variable materials being fly ash (FA), ground granulated blast furnace slag (GGBS), and quicklime. It can be found that the use of fly ash as a mineral admixture not only improves the grout performance substantially but also serves as an important component of backfill material cementitious foam [12], natural hydraulic lime-based mortar [13], clay-cement composite grout [14], etc. Scholars have often measured the comprehensive performance of grout containing mineral dopants based on the study of both the macro-mechanical properties [15,16] and micro-fine characteristics [17,18] of the composite materials and have made progress in stages.…”

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Study on the Physical and Chemical Properties of Cement-Based Grout Containing Coal–Fly Ash

Guo

Zou

et al. 2022

Materials

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To study the physical and chemical properties of grout containing fly ash, Class II fly ash was used as a mineral admixture and mixed with silicate cement to produce grout, and the rheological properties, strength properties, hydration properties, and microscopic mechanism were studied. The results of the study showed the following. The incorporation of fly ash reduced the thixotropic area of the composite cement slurry, which facilitated pumping in the pipeline conveying process. The inclusion of fly ash reduced the yield stress and plastic viscosity of the cement paste, but the rheological index increased and then decreased with the increase in fly ash, and the composite paste had the lowest degree of shear thinning at 30% fly ash inclusion. The incorporation of fly ash reduced the hydration exothermic rate and total hydration exothermic amount of the composite slurry and prolonged the hydration induction period, but the promotion effect of fly ash on the hydration rate of cement was obvious at 10% fly ash admixture. The admixture of fly ash increased the empty volume of the composite slurry, but the effect on the most probable aperture was not significant, and the porosity of the system increased, resulting in a decrease in compressive strength. The effect of adding fly ash on the hydration products was reflected mainly by the C-S-H gel produced by cement hydration and the change in calcium alumina and Ca(OH)2. Fly ash does not directly participate in the hydration reaction of cement, but it can promote cement hydration and increase the reaction rate of cement. By analyzing the rheological properties, mechanical properties, and hydration properties of fly ash composite cement paste, the comprehensive analysis found that the rheological properties are excellent when the fly ash admixture is 20–30%, and the water–cement ratio can be reduced to improve the strength without affecting the pumping demand.

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