The Carbonation of Calcium-Silicate-Hydrate C-S-H in Cement Mortar Studied Using Thermal Analysis and Gas Pycnometer: Determination of the Quantity of Calcium Carbonate Produced and the Increase in Molar Volume

The objective of this work was to examine the microstructural changes caused by the carbonation of normalised cement mortar. Samples were prepared and subjected to accelerated carbonation at 20°C, 65% relative humidity and 20% CO2 concentration. The main contributions of this study were: 1) a new way to determine separately the amount of calcium carbonate CaCO3 produced by the carbonation of portlandite Ca (OH)2 and that associated with the carbonation of calcium-silicate-hydrate C-S-H using only thermal analysis; 2) determination of the increase in the molar volume of the calcium-silicate-hydrate C-S-H due to carbonation using gas pycnometer, which indicated an increase of about 39 cm3 for 1 mole of C3S2H3 carbonated. The results indicated that the amount of CaCO3 produced by the carbonation of C-S-H is higher than that produced by the carbonation of portlandite.

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THE RELATIONSHIP BETWEEN THE DYNAMICS OF DEUTERIUM IN CALCIUM SILICATE HYDRATE AND CURING RELATIVE HUMIDITY MEASURED BY SOLID STATE 2H NMR

Cement Science and Concrete Technology ◽

10.14250/cement.64.82 ◽

2010 ◽

Vol 64 (1) ◽

pp. 82-88

Author(s):

Daisuke MINATO ◽

Toshifumi HIRAOKI ◽

Toyoharu NAWA ◽

Suguru GOTO

Keyword(s):

Solid State ◽

Relative Humidity ◽

Calcium Silicate ◽

Calcium Silicate Hydrate ◽

2H Nmr ◽

The Relationship

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Effect of Blast-Furnace Slag Replacement Ratio and Curing Method on Pore Structure Change after Carbonation on Cement Paste

Materials ◽

10.3390/ma13214787 ◽

2020 ◽

Vol 13 (21) ◽

pp. 4787

Author(s):

Junho Kim ◽

Seunghyun Na ◽

Yukio Hama

Keyword(s):

Blast Furnace ◽

Calcium Carbonate ◽

Pore Structure ◽

Calcium Silicate ◽

Blast Furnace Slag ◽

Calcium Silicate Hydrate ◽

Structure Change ◽

Replacement Rate ◽

Replacement Ratio ◽

Furnace Slag

The frost damage resistance of blast-furnace slag (BFS) cement is affected by carbonation. Hence, this study investigates the carbonation properties of pastes incorporating BFS with different replacement ratios, such as 15%, 45%, and 65% by weight, and different curing conditions, including air and carbonation. The BFS replacement ratio properties, determined by the Ca/Si ratio of calcium silicate hydrate in the cement paste sample, were experimentally investigated using mercury intrusion porosimetry, X-ray diffraction, and thermal analysis. The experimental investigation of the pore structure revealed that total porosity decreased after carbonation. In addition, the porosity decreased at a higher rate as the BFS replacement rate increased. Results obtained from this study show that the chemical change led to the higher replacement rate of BFS, which produced a higher amount of vaterite. In addition, the lower the Ca/Si ratio, the higher the amount of calcium carbonate originating from calcium silicate hydrate rather than from calcium hydroxide. As a result of the pore structure change, the number of ink-bottle pores was remarkably reduced by carbonation. Comparing the pore structure change in air-cured and carbonation test specimens, it was found that as the replacement rate of BFS increased, the number of pores with a diameter of 100 nm or more also increased. The higher the replacement rate of BFS, the higher the amount of calcium carbonate produced compared with the amount of calcium hydroxide produced during water curing. Due to the generation of calcium carbonate and the change in pores, the overall number of pores decreased as the amount of calcium carbonate increased.

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Influence of SBR Latex on the Formation of C-S-H in C3S Paste

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.687.329 ◽

2013 ◽

Vol 687 ◽

pp. 329-334 ◽

Cited By ~ 5

Author(s):

Xu Bo Yue ◽

Ru Wang

Keyword(s):

Calcium Carbonate ◽

Calcium Silicate ◽

Calcium Silicate Hydrate ◽

Silicon Oxide ◽

Tricalcium Silicate ◽

Styrene Butadiene Rubber ◽

Butadiene Rubber ◽

Hydration Time ◽

Silica Ratio ◽

Styrene Butadiene

Tricalcium silicate (C3S) was synthesized at 1500oC using calcium carbonate and silicon oxide. The formation of the hydrates of C3S in the presence of 10% styrene-butadiene rubber (SBR) latex was evaluated. The morphology of the calcium silicate hydrate (C-S-H) was studied using SEM, and the calcium to silica ratio of the C-S-H was studied using EDS. The results show that the SBR latex forms film on the surface of the C3S particles and the C-S-H and delays the hydration of C3S. The C-S-H in the paste modified by SBR latex is shorter and thicker than that in the control at the same hydration time. After 1 day, the calcium to silica ratio of the modified paste is higher than that of the control.

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The Carbon Absorb of Cement-Based Material in the Accelerated Carbonation Test

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.905.318 ◽

2014 ◽

Vol 905 ◽

pp. 318-321

Author(s):

Xiao Xiong Zha ◽

Hai Yang Wang ◽

Gan Lin Feng

Keyword(s):

Carbon Dioxide ◽

Reaction Time ◽

Calcium Carbonate ◽

Greenhouse Gas ◽

Material Property ◽

Building Materials ◽

Cement Mortar ◽

Accelerated Carbonation ◽

The Way

Carbonation is a common influence of cement-based material. And the accelerated carbonation is used in material property modify. With the reaction in the material when carbonating, the carbon dioxide will be solidifying in the material, in the shape of precipitation of calcium carbonate filled the pore. But the ability of the carbon absorbing is unknown, in this paper, some cement-based building materials are took in test, including the aerated brick, cement tile, concrete, and cement mortar. In according to the results, it has found that the carbon absorbing ability is different, and with the carbon absorbing, the strength also increasing. The aerated brick is greatest and the condition of temperature, pressure and reaction time is lowest, which give a reference on the way of the greenhouse gas transform and reduced.

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Effects of the Type of Cement and the Concentration of CO2 on the Carbonation Rate of Portland Mortars

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.556-562.965 ◽

2014 ◽

Vol 556-562 ◽

pp. 965-968

Author(s):

Son Tung Pham ◽

William Prince

Keyword(s):

Thermogravimetric Analysis ◽

Relative Humidity ◽

Accelerated Carbonation ◽

Cement Mortars ◽

Carbonation Of Portlandite ◽

The One

The objective of this study was to examine the influences of the type of cement and the CO2 concentration on the carbonation progress of cement materials. Thermogravimetric analysis were used to follow mineralogical changes of standard CEM I and CEM II mortars which were submitted to an accelerated carbonation at 20% and 50% CO2, 20°C and 65% relative humidity. The results indicated that the carbonation of portlandite is complete in the case of CEM II mortar while there is a persistence of residual portlandite in the case of CEM I mortar. In other words, the carbonation rate of CEM I mortar is slower than the one of CEM II mortar, which is not only because of its greater content of portlandite but also because of the coverage of portlandite crystals by newly formed calcite. These results allow us to conclude that the carbonation rate of cement mortars depends especially on the type of cement while the CO2 concentration does not affect it at all.

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