Effects of curing condition and particle size of aggregate on the expansion and microstructure of dolomitic aggregates cured in TMAH solution

In this paper, the modified microbars prepared by dolomitic aggregates with three kinds of particle size and self-made cement without K+ and Na+ were cured in 1 and 2 N tetramethyl ammonium hydroxide (TMAH) solution at 20°C, 60°C and 80°C, respectively. TMAH was used as curing solution to exclude th...

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Main Authors: Bin Yang, Xiaoxiao Chen, Min Deng
Format: Article
Language:English
Published: The Royal Society 2019-04-01
Series:Royal Society Open Science
Subjects:
Online Access:https://royalsocietypublishing.org/doi/pdf/10.1098/rsos.190044
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spelling doaj-b2f10bbfe2aa4603b557e2f0a56ef9c52020-11-25T03:41:23ZengThe Royal SocietyRoyal Society Open Science2054-57032019-04-016410.1098/rsos.190044190044Effects of curing condition and particle size of aggregate on the expansion and microstructure of dolomitic aggregates cured in TMAH solutionBin YangXiaoxiao ChenMin DengIn this paper, the modified microbars prepared by dolomitic aggregates with three kinds of particle size and self-made cement without K+ and Na+ were cured in 1 and 2 N tetramethyl ammonium hydroxide (TMAH) solution at 20°C, 60°C and 80°C, respectively. TMAH was used as curing solution to exclude the expansion contribution of alkali–silica reaction. Effects of the concentration of TMAH solution, curing temperature and aggregate grain size on the expansion of dolomitic aggregates were systematically investigated to determine the expansion characteristics only caused by alkali–carbonate reaction (ACR). Expansion of modified microbars cured in TMAH solution was measured. The porosities of original and reacted aggregates were also measured. Microstructural studies were carried out by scanning electron microscopy (SEM) and thermo-gravimetric (TG) analysis. The results showed that the aggregate grain size and curing temperature can influence the expansion of modified microbars significantly. When the modified microbars prepared by aggregates with 2.5–5 mm grain size and cured in 1 N TMAH solution at 80°C, the samples exhibited obvious expansion only caused by ACR, which is beneficial to detect the ACR reactivity of dolomitic rocks exclusively in concrete engineering. Based on the pore structure analysis, there was a slight increase (13%) in porosities of aggregates cured for 140 days at 80°C. Rod-like brucite crystals formed in the process of ACR were also found in TG analysis and SEM images.https://royalsocietypublishing.org/doi/pdf/10.1098/rsos.190044alkali–carbonate reactiondolomitic aggregatesexpansionmicrostructure
collection DOAJ
language English
format Article
sources DOAJ
author Bin Yang
Xiaoxiao Chen
Min Deng
spellingShingle Bin Yang
Xiaoxiao Chen
Min Deng
Effects of curing condition and particle size of aggregate on the expansion and microstructure of dolomitic aggregates cured in TMAH solution
Royal Society Open Science
alkali–carbonate reaction
dolomitic aggregates
expansion
microstructure
author_facet Bin Yang
Xiaoxiao Chen
Min Deng
author_sort Bin Yang
title Effects of curing condition and particle size of aggregate on the expansion and microstructure of dolomitic aggregates cured in TMAH solution
title_short Effects of curing condition and particle size of aggregate on the expansion and microstructure of dolomitic aggregates cured in TMAH solution
title_full Effects of curing condition and particle size of aggregate on the expansion and microstructure of dolomitic aggregates cured in TMAH solution
title_fullStr Effects of curing condition and particle size of aggregate on the expansion and microstructure of dolomitic aggregates cured in TMAH solution
title_full_unstemmed Effects of curing condition and particle size of aggregate on the expansion and microstructure of dolomitic aggregates cured in TMAH solution
title_sort effects of curing condition and particle size of aggregate on the expansion and microstructure of dolomitic aggregates cured in tmah solution
publisher The Royal Society
series Royal Society Open Science
issn 2054-5703
publishDate 2019-04-01
description In this paper, the modified microbars prepared by dolomitic aggregates with three kinds of particle size and self-made cement without K+ and Na+ were cured in 1 and 2 N tetramethyl ammonium hydroxide (TMAH) solution at 20°C, 60°C and 80°C, respectively. TMAH was used as curing solution to exclude the expansion contribution of alkali–silica reaction. Effects of the concentration of TMAH solution, curing temperature and aggregate grain size on the expansion of dolomitic aggregates were systematically investigated to determine the expansion characteristics only caused by alkali–carbonate reaction (ACR). Expansion of modified microbars cured in TMAH solution was measured. The porosities of original and reacted aggregates were also measured. Microstructural studies were carried out by scanning electron microscopy (SEM) and thermo-gravimetric (TG) analysis. The results showed that the aggregate grain size and curing temperature can influence the expansion of modified microbars significantly. When the modified microbars prepared by aggregates with 2.5–5 mm grain size and cured in 1 N TMAH solution at 80°C, the samples exhibited obvious expansion only caused by ACR, which is beneficial to detect the ACR reactivity of dolomitic rocks exclusively in concrete engineering. Based on the pore structure analysis, there was a slight increase (13%) in porosities of aggregates cured for 140 days at 80°C. Rod-like brucite crystals formed in the process of ACR were also found in TG analysis and SEM images.
topic alkali–carbonate reaction
dolomitic aggregates
expansion
microstructure
url https://royalsocietypublishing.org/doi/pdf/10.1098/rsos.190044
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