Rehydration activity of hydrated cement paste exposed to high temperature

Xuan, Dongxing; Shui, Zhong He

doi:10.1002/fam.1067

Cited by 52 publications

(40 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The above-mentioned components of RCM facilitate further hydration and reaction with new cement paste, which cause the improvement of physical properties of cement composites. This is confirmed by the observations of other authors, who have noticed the content of non-hydrated cement, calcium hydroxide (CH), and dicalcium silicate (C 2 S) in RCM, which are capable of hydration and creation of rehydration products [19,20,22].…”

Section: Thermogravimetry (Tg) and Differential Thermal Analysis (Dta)supporting

confidence: 80%

“…The compact C-S-H phase can be observed in Figures 12 and 13. The compact microstructure may result from strong bonding of high-quality recycling mortar containing C-S-H phases to the components of new paste, as well as the developed surface of the recycled fraction due to applied thermal and mechanical treatment [20]. Micrographs of the microstructure of cement composites with RCM are presented in Figures 12 and 13.…”

Section: Sem Images Analysismentioning

confidence: 99%

“…Some researchers [19,20] studied the rehydration reactivity of fine fraction from recycled concrete after its heating at different temperatures. The results confirm that cement paste heated at a sufficiently high temperature is dehydrated.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The Properties of Composites with Recycled Cement Mortar Used as a Supplementary Cementitious Material

Kalinowska-Wichrowska

Kosior‐Kazberuk

Pawluczuk

2019

Materials

View full text Add to dashboard Cite

The process of recycling concrete rubble is accompanied by the formation of a large amount of fine fraction, which cannot be reused as aggregate. The results of research on the possibility of using recycled cement mortar (RCM), obtained during concrete recycling, as a cementitious supplementary material, are presented. The experimental research was carried out on the basis of two variables determining the recycling process: X 1 -temperature (range of variation 288-712 • C) and X 2 -time (range of variation 30-90 min) of thermal treatment of concrete rubble. The experiment included 10 series of new composites made with RCMs subjected to different variants of thermal treatment, and two additional control series. The best treatment parameters were determined based on the assessment of selected physical and mechanical properties of the new cement composites, as well as the analysis of characteristics and microstructure of RCM. The test results showed that proper thermal treatment of concrete rubble makes it possible to obtain a high-quality fine fraction, which has the properties of an active addition and can be used as a partial replacement for cement in mortars and concretes.

show abstract

Section: Thermogravimetry (Tg) and Differential Thermal Analysis (Dta)supporting

confidence: 80%

Section: Sem Images Analysismentioning

confidence: 99%

See 1 more Smart Citation

The Properties of Composites with Recycled Cement Mortar Used as a Supplementary Cementitious Material

Kalinowska-Wichrowska

Kosior‐Kazberuk

Pawluczuk

2019

Materials

View full text Add to dashboard Cite

show abstract

“…Nevertheless, the residual compressive strength of all concretes is higher than that measured at elevated temperatures and rehydration of hydration products can be the reason for strength gain after cooling. It is observed by many researchers that re‐curing of heated concretes at various curing methods yielded different levels of improvement in mechanical properties of concrete through formation of new hydration products due to rehydration which also reduces the porosity of the coarse pores of heated concrete . The above mechanisms strengthened the ITZ through reducing its porosity in both concretes and hence, gain some compressive strength after cooling.…”

Section: Resultsmentioning

confidence: 99%

Mechanical properties of concrete containing recycled coarse aggregate at and after exposure to elevated temperatures

Shaikh

2017

Structural Concrete

View full text Add to dashboard Cite

This paper presents the effect of recycled coarse aggregate (RCA) of 50% and 100% by wt. on compressive strength and elastic modulus of concrete at elevated temperatures of 600 and 800 °C. The residual compressive strengths of above recycled aggregate concretes after exposure to elevated temperatures are also evaluated and compared to those measured during heating. The effect of polypropylene (PP) fibers on residual compressive strength and cracking behavior of above recycled aggregate concretes after exposure to elevated temperatures is also evaluated in this study. Results show that the loss of compressive strength of recycled aggregate concretes at 600 and 800 °C is slightly higher (about 10%) than its counterpart control concrete containing natural coarse aggregates. Concrete containing 100% RCA exhibited about 50% loss of its ambient temperature compressive strength at 800 °C, which is about 25% less in concrete containing 50% RCA. The residual compressive strength, which is measured after cooling of heated specimens, of both recycled aggregate concretes and control concrete is higher at both elevated temperatures. The measured elastic modulus of both recycled aggregate concretes show no significant reduction compared to their counterpart control concrete at both elevated temperatures. A strong correlation between elastic modulus and square root of compressive strength of recycled aggregate concretes is observed at elevated temperatures. The model proposed in Eurocode to predict the elevated temperature compressive strength and elastic modulus agrees well with the measured values for recycled aggregate concretes. The addition of PP fibers reduced the residual compressive strength of concrete containing 100% RCA at both temperatures with significant reduction at 800 °C. However, mixed results are obtained in the case of concrete containing 50% RCA. The cracking patterns of concrete containing RCA and those containing PP fibers also correlated well with the observed residual compressive strength results.

show abstract

“…Ao mesmo tempo, muitos autores têm estudado as fases formadas pela hidratação, desidratação e reidratação de pastas de cimento [4,[14][15][16][17]. Análises por termogravimetria (TGA), difração de raios X (DRX), espectroscopia no infravermelho por transformada de Fourier (FTIR) e análise térmica diferencial (DTA) têm sido amplamente empregadas nestes estudos [5,6,[18][19][20][21][22].…”

Section: Introductionunclassified

Efeito do teor de água e tamanho de partícula na decomposição térmica de pastas de cimento moídas

et al. 2020

View full text Add to dashboard Cite

RESUMO Um método alternativo para produção de concretos ecoeficientes seria a substituição parcial de cimento Portland por resíduos de pastas e argamassas submetidas a um tratamento termomecânico. Neste contexto, este estudo avalia a influência da relação água/cimento (a/c) e do tamanho médio das partículas na decomposição térmica do cimento hidratado. Pastas de cimento com três relações a/c (0,40, 0,50 e 0,60) e curadas por 28 dias foram moídas para obtenção de granulometrias com tamanho médio de 0,60 mm e 0,15 mm. A decomposição térmica das pastas foi analisada por termogravimetria (TGA), difração de raios X (DRX) e espectroscopia no infravermelho por Transformada de Fourier (FTIR). A análise de TGA indica que o teor de água quimicamente combinada é favorecido pelo aumento da relação a/c entre 0,40 e 0,50, mas é constante para a/c de 0,50 e 0,60. A redução do tamanho médio quase não interfere nas curvas de TGA. De acordo com as análises por DRX e TGA, a maior parte dos hidratos se decompõe até 500-550°C, enquanto que silicatos de cálcio e aluminatos de cálcio similares às fases anidras do cimento Portland foram detectados na pasta aquecida a 750°C. Assim, temperaturas mais altas seriam necessárias para a completa recuperação do cimento anidro em pastas hidratadas.

show abstract

Rehydration activity of hydrated cement paste exposed to high temperature

Cited by 52 publications

References 11 publications

The Properties of Composites with Recycled Cement Mortar Used as a Supplementary Cementitious Material

The Properties of Composites with Recycled Cement Mortar Used as a Supplementary Cementitious Material

Mechanical properties of concrete containing recycled coarse aggregate at and after exposure to elevated temperatures

Efeito do teor de água e tamanho de partícula na decomposição térmica de pastas de cimento moídas

Contact Info

Product

Resources

About