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James Margeson - One of the best experts on this subject based on the ideXlab platform.

  • is Alkali carbonate Reaction just a variant of Alkali Silica Reaction acr asr
    Cement and Concrete Research, 2010
    Co-Authors: P E Grattanbellew, Lyndon D Mitchell, James Margeson
    Abstract:

    Abstract The mechanism of the Alkali–carbonate Reaction (ACR) has been recognized as being different from that of the more common Alkali–Silica Reaction (ASR). However, the identification of Alkali–Silica gel in ACR concrete from Cornwall, Ontario, Canada by Katayama, in 1992 raised the possibility that ASR was at least playing a role in the ACR Reaction. The acid insoluble residues of the ACR aggregate from Kingston, along with two other aggregates were analyzed to determine what might be contributing to the Reaction. The acid insoluble residue of the ACR Kingston rock contains 96% quartz of high solubility in NaOH. Good correlation was found between the amount of quartz and expansion of concrete prisms indicating that the expansion was due mainly to an Alkali–Silica Reaction. This conclusion is supported by observations, in 2008, by Katayama of gel in thin sections of concrete made with the Kingston aggregate. It is concluded that ACR = ASR.

  • Is Alkali–carbonate Reaction just a variant of Alkali–Silica Reaction ACR = ASR?
    Cement and Concrete Research, 2010
    Co-Authors: P.e. Grattan-bellew, Lyndon D Mitchell, James Margeson
    Abstract:

    Abstract The mechanism of the Alkali–carbonate Reaction (ACR) has been recognized as being different from that of the more common Alkali–Silica Reaction (ASR). However, the identification of Alkali–Silica gel in ACR concrete from Cornwall, Ontario, Canada by Katayama, in 1992 raised the possibility that ASR was at least playing a role in the ACR Reaction. The acid insoluble residues of the ACR aggregate from Kingston, along with two other aggregates were analyzed to determine what might be contributing to the Reaction. The acid insoluble residue of the ACR Kingston rock contains 96% quartz of high solubility in NaOH. Good correlation was found between the amount of quartz and expansion of concrete prisms indicating that the expansion was due mainly to an Alkali–Silica Reaction. This conclusion is supported by observations, in 2008, by Katayama of gel in thin sections of concrete made with the Kingston aggregate. It is concluded that ACR = ASR.

P E Grattanbellew - One of the best experts on this subject based on the ideXlab platform.

  • is Alkali carbonate Reaction just a variant of Alkali Silica Reaction acr asr
    Cement and Concrete Research, 2010
    Co-Authors: P E Grattanbellew, Lyndon D Mitchell, James Margeson
    Abstract:

    Abstract The mechanism of the Alkali–carbonate Reaction (ACR) has been recognized as being different from that of the more common Alkali–Silica Reaction (ASR). However, the identification of Alkali–Silica gel in ACR concrete from Cornwall, Ontario, Canada by Katayama, in 1992 raised the possibility that ASR was at least playing a role in the ACR Reaction. The acid insoluble residues of the ACR aggregate from Kingston, along with two other aggregates were analyzed to determine what might be contributing to the Reaction. The acid insoluble residue of the ACR Kingston rock contains 96% quartz of high solubility in NaOH. Good correlation was found between the amount of quartz and expansion of concrete prisms indicating that the expansion was due mainly to an Alkali–Silica Reaction. This conclusion is supported by observations, in 2008, by Katayama of gel in thin sections of concrete made with the Kingston aggregate. It is concluded that ACR = ASR.

Lyndon D Mitchell - One of the best experts on this subject based on the ideXlab platform.

  • is Alkali carbonate Reaction just a variant of Alkali Silica Reaction acr asr
    Cement and Concrete Research, 2010
    Co-Authors: P E Grattanbellew, Lyndon D Mitchell, James Margeson
    Abstract:

    Abstract The mechanism of the Alkali–carbonate Reaction (ACR) has been recognized as being different from that of the more common Alkali–Silica Reaction (ASR). However, the identification of Alkali–Silica gel in ACR concrete from Cornwall, Ontario, Canada by Katayama, in 1992 raised the possibility that ASR was at least playing a role in the ACR Reaction. The acid insoluble residues of the ACR aggregate from Kingston, along with two other aggregates were analyzed to determine what might be contributing to the Reaction. The acid insoluble residue of the ACR Kingston rock contains 96% quartz of high solubility in NaOH. Good correlation was found between the amount of quartz and expansion of concrete prisms indicating that the expansion was due mainly to an Alkali–Silica Reaction. This conclusion is supported by observations, in 2008, by Katayama of gel in thin sections of concrete made with the Kingston aggregate. It is concluded that ACR = ASR.

  • Is Alkali–carbonate Reaction just a variant of Alkali–Silica Reaction ACR = ASR?
    Cement and Concrete Research, 2010
    Co-Authors: P.e. Grattan-bellew, Lyndon D Mitchell, James Margeson
    Abstract:

    Abstract The mechanism of the Alkali–carbonate Reaction (ACR) has been recognized as being different from that of the more common Alkali–Silica Reaction (ASR). However, the identification of Alkali–Silica gel in ACR concrete from Cornwall, Ontario, Canada by Katayama, in 1992 raised the possibility that ASR was at least playing a role in the ACR Reaction. The acid insoluble residues of the ACR aggregate from Kingston, along with two other aggregates were analyzed to determine what might be contributing to the Reaction. The acid insoluble residue of the ACR Kingston rock contains 96% quartz of high solubility in NaOH. Good correlation was found between the amount of quartz and expansion of concrete prisms indicating that the expansion was due mainly to an Alkali–Silica Reaction. This conclusion is supported by observations, in 2008, by Katayama of gel in thin sections of concrete made with the Kingston aggregate. It is concluded that ACR = ASR.

A Carse - One of the best experts on this subject based on the ideXlab platform.

  • SUITABLE INTERVENTION STRATEGIES FOR STRUCTURES AFFECTED BY THE Alkali-Silica Reaction
    2020
    Co-Authors: A Carse
    Abstract:

    The purpose of this paper is to provide a detailed review of the issues facing the maintenance engineer in relation to repairing a bridge structure affected by Alkali-Silica Reaction cracking. The bridge structure chosen consists of an original section of 8 prestressed T girders and was subsequently widened in 1990 with 11 deck units on the western side and 9 deck units on the eastern side. All of the cracking previously identified by others was reported as being confined to the new deck units in both widening sections. As a result of the work performed in this report, Alkali-Silica Reaction (ASR) was determined as the primary mechanism causing the observed cracking in the prestressed deck units used in the widening of this bridge in 1990. An approach to the rehabilitation of this structure is outlined and has a degree of urgency in relation to the satisfactory long term performance of this structure. (a) For the covering entry of this conference, please see ITRD abstract no. E210200.

  • Suitable intervention strategies for structures affected by Alkali-Silica Reaction (ASR)
    2020
    Co-Authors: A Carse
    Abstract:

    The purpose of this paper is to provide a review of the issues in relation to repairing bridge structures affected by Alkali-Silica Reaction cracking. The bridge structures chosen cover problems with a superstructure and also a substructure. The superstructure example consists of an original section of 8 prestressed T girders and was subsequently widened in 1990 with 11 deck units on the Western side and 9 deck units on the Eastern side. All of the cracking previously identified by others was reported as being confined to the new deck units in both widening sections. Field inspection indicates the soffit of the deck units is very close to the high water mark in the tidal creek. As a result of the work performed in this report, Alkali-Silica Reaction (ASR) was determined as the primary mechanism causing the observed cracking in the prestressed deck units used in the widening of this bridge in 1990. An approach to the rehabilitation of this structure is outlined which had a degree of urgency in relation to the satisfactory long-term performance of this structure. (a) For the covering entry of this conference, please see ITRD abstract no. E211602.

Xiangyin Mo - One of the best experts on this subject based on the ideXlab platform.

  • Investigation of structural properties associated with Alkali-Silica Reaction by means of macro- and micro-structural analysis
    Materials Characterization, 2007
    Co-Authors: Xiangyin Mo, Benoit Fournier
    Abstract:

    Abstract Structural properties associated with Alkali–Silica Reaction were systematically investigated by means of macro-structural accelerated mortar prism expansion levels testing, combined with micro-structural analysis. One part of this study is to determine the reactivity of the aggregate by means of accelerated mortar bar tests, and also to evaluate perlite aggregate constituents, especially the presence of deleterious components and find main causes of the Alkali–Silica Reaction, which was based on the petrographic studies by optical microscope and the implication of X-ray diffraction on the aggregate. Results implied that the aggregate was highly Alkali–Silica reactive and the main micro-crystalline quartz-intermediate character and matrix that is mainly composed of chalcedony are potentially suitable for Alkali–Silica Reaction. The other part is to study the long-term effect of lithium salts against Alkali–Silica Reaction by testing accelerated mortar prism expansion levels. The macro-structural results were also consistent with the micro-structural mechanisms of Alkali–Silica Reaction of mortar prisms containing this aggregate and the effect of chemical admixtures by means of the methods of scanning electron microscope–X-ray energy-dispersive spectroscopy and X-ray diffraction. It was indicated by these techniques that lithium salts, which were introduced into concrete containing reactive aggregate at the mixing stage, suppressed the Alkali–Silica Reaction by producing non-expansive crystalline materials.

  • long term effectiveness and mechanism of lioh in inhibiting Alkali Silica Reaction
    Cement and Concrete Research, 2003
    Co-Authors: Xiangyin Mo, Chenjie Yu, Zhongzi Xu
    Abstract:

    Excess expansion and cracking of concrete occurs when some of the Alkali reactive rocks are used as coarse aggregate in concrete made with high-Alkali cement. Although lithium compounds are one of the techniques used to reduce the effects of Alkali-Silica Reaction ASR), the long-term effectiveness has not been tested thoroughly and the evidence to prove such effects is also lacking. This article used a practical Alkali reactive aggregate-Beijing aggregate to test the long-term effectiveness of LiOH in inhibiting Alkali-aggregate Reaction (AAR) expansion. The mortar bars used had been cured at 80 deg C. for 3 years after being autoclaved for 24 h at 150 deg C. Under these conditions, LiOH was able to inhibit long-term Alkali-Silica Reaction (ASR) expansion effectively. The authors include electron micrographs that illustrate the processes under discussion.