Engineering properties of amorphous silica as a new natural pozzolan for use in concrete

Davraz, Metin; Gündüz, Lütfullah

doi:10.1016/j.cemconres.2004.11.016

Cited by 69 publications

(30 citation statements)

References 1 publication

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“…It is well known that amorphous silica promotes the pozzolanic reaction with portlandite (calcium hydroxide) present in cement-based materials. This reaction produces calcium silicate hydrates that are responsible for an additional increment in the strength and chemical resistance [30].…”

Section: Resultsmentioning

confidence: 99%

Influence of fired clay brick waste additions on the durability of mortars

Schackow

Stringari

Senff

et al. 2015

Cement and Concrete Composites

130

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Section: Resultsmentioning

confidence: 99%

Influence of fired clay brick waste additions on the durability of mortars

Schackow

Stringari

Senff

et al. 2015

Cement and Concrete Composites

130

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“…The ASTM C618 [1] defines mineral admixtures that can be used for mixing concrete, such as diatomaceous earths, opaline chert and volcanic ashes, among others, and the physical performance of construction materials made with these natural additives has been investigated to widen their applications [2,3]. Also, industrial byproducts such as fly ash and slags from metallurgy have been utilized for construction materials to reduce waste volumes [4].…”

Section: Introductionmentioning

confidence: 99%

Key Factors Affecting Strength Development of Steel Slag-Dredged Soil Mixtures

et al. 2018

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Some of the steel slag from ironworks and dredged soils from marine and waterfront engineering work are partially treated as waste. However, a mixture of these two kinds of waste has the potential to be used as construction materials when mixed, due to chemical reactions forming secondary phases. Utilizing waste of such kind as a resource will help to improve sustainability in society by reducing waste and replacing virgin resources such as cement. Recently, it was reported that mixtures of steel slag and dredged soil hardens under specific conditions. The phase compositions of dredged soils and steel slags vary depending on the quantity of each component, which results in unpredictable strength development of mixtures. The effect of the variations in the components of steel slags and dredged soils on strength development of the mixtures is not yet clear, limiting the utilization of both materials. Understanding the hardening mechanisms of the mixtures will enable the prediction of strength development. Focusing on the variations in the components in steel slags and, especially of dredged soils, this study aims to identify the components in both materials that affect the secondary phase formation that are responsible for strength development. We found support for suggestions that calcium silicate hydrate, C-S-H, is one of the secondary phases responsible for the strength development of the mixtures. From a comparison of two kinds of steel slags and various dredged soils, the amount of portlandite in the steel slags and the amount of amorphous silica in the dredged soils are suggested as a couple of the key components of starting materials involved in the C-S-H formation.

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“…The presence of diffuse reflection at 22°< 2θ < 26°r epresented the amorphous silica 10,11 . Although the XRF results show that CaO content in the BA was approximately 6%, the main peaks of portlandite (Ca(OH) 2 ) were not observed.…”

Section: Methodsmentioning

confidence: 99%

Strength and microstructure development in Bangkok clay stabilized with calcium carbide residue and biomass ash

Vichan¹,

Rachan²,

Horpibulsuk³

2013

ScienceAsia

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A mixture of biomass ash (BA) and calcium carbide residual (CCR) was used as a cementing agent for stabilization of soft Bangkok clay. The improvement in unconfined compressive strength of stabilized clay depends on the initial soil water content, binder content (B), CCR:BA ratio, and curing time. The strength improvement can be classified into two zones: active and inert. In the active zone (B = 5-15%), the Ca(OH) 2 content from the CCR is high and there are insufficient natural pozzolanic materials in the clay for the reaction. The input of BA increases the SiO2 content and induces the strength development. In the inert zone, (high binder content, B > 15%), the free lime causes unsoundness and results in insignificant strength development. The hydration products from the pozzolanic reaction (ettringite and a calcium aluminate silicate hydrate compound, gismondine) are identified by microstructural analysis via X-ray diffraction (XRD), scanning electron microscope with energy dispersive X-ray spectroscopy (SEM with EDS), and X-ray fluorescence. SEM images show the compact morphology of the stabilized clay as the result of the increase in curing time and binder content. Over time, the cementitious products fill in the pore space, causing denser morphology and higher cementation bond strength between the clay clusters. The clay stabilized by XRD showed no reduction in the intensity of the reflection of the both quartz and kaolinite throughout the curing times. This implies that the amorphous silica from the glass of the BA is more reactive in dissolution in the CCR than the crystalline phase of quartz and kaolin in clay.

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Engineering properties of amorphous silica as a new natural pozzolan for use in concrete

Cited by 69 publications

References 1 publication

Influence of fired clay brick waste additions on the durability of mortars

Influence of fired clay brick waste additions on the durability of mortars

Key Factors Affecting Strength Development of Steel Slag-Dredged Soil Mixtures

Strength and microstructure development in Bangkok clay stabilized with calcium carbide residue and biomass ash

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