Early carbonation curing effects on the microstructure of high initial strength Portland cement pastes

After submitted to early age carbonation curing, mechanical and physical properties of high initial strength sulfate resistant Portland cement (HS SR PC) pastes were investigated, which were compared to those of non-carbonated reference pastes. Carbonation was performed for 1 and 24 hours, at the best conditions of CO2capturing, previously determined by the authors. Despite the compressive strength and elastic modulus of the 1h carbonated pastes were slightly higher than those of the reference pastes, their absorbed water content and porosity was slightly higher than that of the reference. In the case of 24h carbonation, its compressive strength decreases significantly because of its much higher porosity, although the new solid carbonated calcium silicate phase presents a much higher specific mass than those of the solid phases of the 1 hour and non-carbonated pastes.

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A study of CO2 capture by high initial strength Portland cement pastes at early curing stages by new non-conventional thermogravimetry and non-conventional differential thermal analysis

Journal of Thermal Analysis and Calorimetry ◽

10.1007/s10973-017-6326-0 ◽

2017 ◽

Vol 129 (3) ◽

pp. 1341-1352 ◽

Cited By ~ 5

Author(s):

Alex Neves Junior ◽

Romildo Dias Toledo Filho ◽

Jo Dweck ◽

Eduardo de Moraes Rego Fairbairn

Keyword(s):

Thermal Analysis ◽

Differential Thermal Analysis ◽

Portland Cement ◽

Co2 Capture ◽

Cement Pastes ◽

Initial Strength

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Hydration and Dehydration of High Initial Strength Portland Cement Type CP V - ARI

Materials Science Forum ◽

10.4028/www.scientific.net/msf.869.106 ◽

2016 ◽

Vol 869 ◽

pp. 106-111

Author(s):

Aloízio Geraldo de Araújo Jr. ◽

Leandro José da Silva ◽

Túlio Hallak Panzera ◽

Adriano Galvão da Souza Azevedo ◽

Kurt Strecker

Keyword(s):

Portland Cement ◽

Cement Paste ◽

Elevated Temperatures ◽

Morphological Changes ◽

Heat Treating ◽

Gravimetric Analysis ◽

Hydrated Cement ◽

Cement Pastes ◽

Initial Strength ◽

Hydration And Dehydration

It is known that the hydration of cement paste is influenced by a variety of factors, it is also known that some hydration products are gradually dehydrated at elevated temperatures. In doing so, different author studied the dehydration of hydrated cement pastes under different condition. In this work, samples of Hydrated Cement Paste (HCP) were prepared from Portland cement of high initial strength (CP V-ARI) with a water/cement ratio of 0.5. The morphological changes during hydration and dehydration by subsequent heat-treatments were analyzed by X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR). Thermal Gravimetric Analysis (TGA) was used to study the thermal stability of the HCP. Dehydrated cement powder samples (DCP) were obtained heat treating samples of HCP at 300, 500, 700 and 900°C. After 7 days of curing HCP samples exhibited no significant changes in its structure. HCP dehydrated at 500°C showed the absence of Ca (OH)2 and calcium silicate hydrate. At 700°C the formation of β-2CaO.SiO2, 3CaO.SiO2 and CaO is observed. During heat treatment at 900°C the HCP revealed a significant mass loss of 36%.

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