塩化カルシウム溶液による各種セメント硬化体の劣化

Mori, Hajime; Kuga, Ryuichiro; Ogawa, Shoichi; Kubo, Yoshimi

doi:10.14250/cement.66.79

Cited by 5 publications

(3 citation statements)

References 3 publications

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“…X-ray diffraction, 10,14 optical microscopy, 14,15 and scanning electron microscopy 14,15 results indicate that CAOXY forms with CaCl 2 and MgCl 2 but not with NaCl. Pastes exposed to NaCl did not show any interaction with CH or any chemical deterioration, 10 that cementitious materials exposed to CaCl 2 show large decreases in compressive strength, 9,10 but those exposed to NaCl 10 do not. Measurements of dynamic modulus using a longitudinal guarded comparative calorimeter coupled with acoustic emission show reductions in dynamic modulus with CaCl 2 and MgCl 2 but not with NaCl.…”

Section: Introductionmentioning

confidence: 92%

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Calcium Oxychloride Formation Potential in Cementitious Pastes Exposed to Blends of Deicing Salt

Suraneni

Monical

Unal

et al. 2017

ACI Materials Journal

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Section: Introductionmentioning

confidence: 92%

“…This reaction leads to the formation of calcium oxychloride, a deleterious reaction product that damages concrete pavements. 7 The reasons for the damage [8][9][10][11] are currently unknown, though crystallization pressure, 8 "disruptive hydraulic pressure," 9 and "expansive pressure" 10 have been suggested as possible reasons.…”

Section: Introductionmentioning

confidence: 99%

Calcium Oxychloride Formation Potential in Cementitious Pastes Exposed to Blends of Deicing Salt

Suraneni

Monical

Unal

et al. 2017

ACI Materials Journal

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“…This damage is characterized by a flaking of the hydrated cement paste, which results in the joints filling with flakes of concrete and aggregates in the joints as shown in Figure 1 (3). Studies clearly show that CAOXY forms when cementitious materials are exposed to CaCl 2 and MgCl 2 at low temperatures; this CAOXY formation is inevitably accompanied by large reductions in compressive strength (8)(9)(10)(11). However, the presence of CAOXY in damaged field concretes is difficult to verify, as CAOXY is not stable when temperature and relative humidity change (12).…”

mentioning

confidence: 99%

Use of Fly Ash to Minimize Deicing Salt Damage in Concrete Pavements

Suraneni

Azad

Isgor

et al. 2017

Transportation Research Record: Journal of the Transportation R

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Premature damage has been observed at the joints in numerous concrete pavements where calcium chloride and magnesium chloride deicing salts have been used. This damage results from a reaction between the deicing salt and the calcium hydroxide (CH) in the hydrated cement paste. This reaction leads to the formation of an expansive product known as calcium oxychloride (CAOXY). The use of supplementary cementitious materials as a replacement for cement has been proposed to reduce the CH that is available in the mixture to react with the deicing salts. Reducing the CH can reduce the amount of CAOXY that forms. In this study, mixtures representative of paving concrete were made with cements and fly ashes from across the country. CH amounts were determined by using thermogravimetric analysis, and CAOXY amounts were determined by using low-temperature differential scanning calorimetry. Various replacement levels of fly ash were used to demonstrate that the main parameter that influences the amounts of CH and CAOXY that form is the replacement level of fly ash. This paper proposes that a prescriptive specification requiring 35% cement replacement by volume with fly ash would reduce the damage caused by CAOXY formation and further proposes a performance specification to limit the CAOXY formation to below 15 g/100 g paste.

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