Effect of Electron Beam and Heat Treatment on the Reactivity of Aggregates and Mineral Additives towards Alkali-Silica Reaction in Portland Cement Compositions

Electron beam (EB) and heat treatment of silica-containing aggregates and mineral additives for Portland cement mortars is shown to affect their activity in alkali-silica reaction (ASR) damaging concrete structures. In the case of ordinary mortar based on the sand free of alkali-reactive inclusions, both heating to 900°C and EB processing result in a significant increase of reactivity growing with the absorbed dose in the range from 100 to 600 kGy and correlating with the increase in the content of acidic hydroxyl groups on the surface. For sand with reactive chalcedony inclusions, EB treatment results in the growth of their reactivity while heating provides its significant decrease. In case of mineral additives such as silica fume and metakaolin known as very effective ASR-inhibitors, similar processing leads to the increase of their activity in mitigation of ASR. The observed effect is promising for simulation of expansion processes caused by ASR and enhancement of concrete structure resistance to alkali destruction during exploration.

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Effects of an early or a late heat treatment on the microstructure and composition of inner C-S-H products of Portland cement mortars

Cement and Concrete Research ◽

10.1016/s0008-8846(01)00670-6 ◽

2002 ◽

Vol 32 (2) ◽

pp. 269-278 ◽

Cited By ~ 55

Author(s):

C Famy ◽

K.L Scrivener ◽

A Atkinson ◽

A.R Brough

Keyword(s):

Heat Treatment ◽

Portland Cement ◽

Cement Mortars

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The clays after heat treatment as the concrete active mineral additive

MATEC Web of Conferences ◽

10.1051/matecconf/201817003021 ◽

2018 ◽

Vol 170 ◽

pp. 03021

Author(s):

Olga Bazhenova ◽

Sofia Bazhenova ◽

V. Nemirova ◽

Dmitriy Bazhenov

Keyword(s):

Heat Treatment ◽

Portland Cement ◽

Raw Material ◽

Cement Stone ◽

Material Resources ◽

Mineral Additive ◽

Granulated Slag ◽

Technical Properties ◽

Mineral Additives ◽

Active Mineral Additives

Active mineral additives are one of the most common components of cement systems now. They are entered cements of increase in extent of hydration, the directed formation of structure of a cement stone from more stable hydrate phases of the lowered basicity, for the purpose of improvement of construction and technical properties of cements, by cutting of costs of fuel raw material resources for their production, giving to cements of some specific properties. In work the possibility of use as active mineral additives not only the granulated slags, but also local clays which industrially can give certain puzzolan properties are considered. It is proved that heat treatment of clay breeds significantly increases their puzzolan activity that does them suitable for use as active mineral additive instead of the domain granulated slag by production of the portland cement.

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The Impact of Aluminum- and Iron-Bearing Admixtures on the Resistance of Portland Cement Mortars to Alkali-Silica Reaction and Sulfate Attack

Materials Sciences and Applications ◽

10.4236/msa.2015.66058 ◽

2015 ◽

Vol 06 (06) ◽

pp. 539-548

Author(s):

Alexey Brykov ◽

Anna Anisimova ◽

Natalya Rozenkova ◽

Mohammed Hadi ◽

Maxim Mokeev

Keyword(s):

Portland Cement ◽

Sulfate Attack ◽

Alkali Silica Reaction ◽

Cement Mortars ◽

The Impact ◽

Iron Bearing

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Alkali-silica reaction (ASR) - Investigation of crystallographic parameters of natural sands by backscattered electron diffraction

Revista IBRACON de Estruturas e Materiais ◽

10.1590/s1983-41952021000300008 ◽

2021 ◽

Vol 14 (3) ◽

Author(s):

Kleber Franke Portella ◽

Leonardo Evangelista Lagoeiro ◽

Jeferson Luiz Bronholo ◽

Dayane de Cristo Miranda ◽

Mariana D’Orey Gaivão Portella Bragança ◽

...

Keyword(s):

Electron Diffraction ◽

Portland Cement ◽

Alkali Silica Reaction ◽

X Ray ◽

Electron Backscattering ◽

Electron Backscattering Diffraction ◽

Cement Mortars ◽

Backscattered Electron ◽

Crystallographic Planes ◽

Mortar Bar

abstract: This study involved analyzing several natural sands to ascertain the possible causes for distress due to ASR. The analyses were performed using the following techniques: X-ray diffractometry, accelerated mortar bar tests (AMBT), electron backscattering diffraction and elementary chemistry analyses, by FEG-SEM/EBSD/EDS. These experiments allowed identifying the presence of several mineral composites (such as microcline, anorthite, among others), as well as the microstructural-crystallographic planes of quartz (such as the Dauphiné type). From the results it could be inferred that the multiple techniques used, especially the FEG-SEM / EBSD, proved to be promising in the analysis of the ASR potential of sands for use in Portland cement mortars and concretes.

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