Influence of Microstructural Changes on Some Macro Physical Properties of Cement Mortar during Accelerated Carbonation

The objective of this work was to examine the microstructural changes caused by the carbonation of normal mortar. Samples were prepared and subjected to accelerated carbonation at 20°C, 65% relative humidity and 20% CO2concentration. The evolutions of the pore size distribution and the specific surface area during carbonation were calculated from the adsorption - desorption isotherms of water vapour and nitrogen. Conflicts observed in the results showed that the porous domains explored by these two methods are not the same due to the difference in molecular sizes of nitrogen and water. These two techniques therefore help to complementarily evaluate the effects of carbonation. The study also helped to explain why results in the literature diverge greatly on the influence of carbonation on specific surface area.

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A Study on the Black Colored Expression Properties and Physical Properties of Cement Mortar Using Granulated Blast Furnace Slag

Science of Advanced Materials ◽

10.1166/sam.2015.2080 ◽

2015 ◽

Vol 7 (1) ◽

pp. 63-67

Author(s):

Hong-Seok Jang ◽

Young-Teak Lim ◽

Hyoung-Seok So ◽

Seung-Young So

Keyword(s):

Blast Furnace ◽

Physical Properties ◽

Blast Furnace Slag ◽

Cement Mortar ◽

Granulated Blast Furnace Slag ◽

Furnace Slag

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Self-Healing Effect Caused by Accelerated Carbonation of Thermally Damaged Cement Mortar: Changes in Microstructural and Macroscopic Properties

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.529.36 ◽

2014 ◽

Vol 529 ◽

pp. 36-40

Author(s):

Son Tung Pham ◽

William Prince

Keyword(s):

Electrical Resistivity ◽

High Temperature ◽

Cement Mortar ◽

Nitrogen Adsorption ◽

The Self ◽

Size Distributions ◽

Self Healing ◽

Accelerated Carbonation ◽

Healing Effect ◽

Macroscopic Properties

The objective of this work was to examine the influence of accelerated carbonation on the microstructural and macroscopic properties of thermally damage cement mortar. A normalised CEM II mortar was treated at 500°C then submitted to carbonation at 20°C, 65% relative humidity and 20% of CO2 concentration. The pores size distributions were determined from nitrogen adsorption. We also followed changes in electrical resistivity and ultrasonic velocity. The results showed that losses of macroscopic properties caused by cracks appeared at high temperature were restored due to carbonation. This highlighted the self-healing effect by accelerated carbonation which allowed the thermally damaged mortar to recover its initial properties.

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Research on the Relationship between Thermal Conductivity and Porosity during Carbonation of Cement Materials

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1065-1069.1838 ◽

2014 ◽

Vol 1065-1069 ◽

pp. 1838-1841

Author(s):

Son Tung Pham

Keyword(s):

Thermal Conductivity ◽

Thermal Properties ◽

Cement Mortar ◽

Total Porosity ◽

Accelerated Carbonation ◽

Experimental Campaign ◽

Hydrostatic Weighing ◽

Specific Material ◽

The Relationship ◽

Microstructural Studies

The objective of this work was to examine the relationships that may exist between porosity and thermal conductivity with particular reference to normalized cement mortar which is most commonly found in civil engineering. Samples were prepared and subjected to accelerated carbonation at 20°C, 65% relative humidity and 20% CO2 concentration. We investigated the evolution of the total porosity measured by hydrostatic weighing and of the thermal properties measured by Hotdisk method. This experimental campaign allowed relating the total porosity and the thermal conductivity before and during carbonation. These results can be used for further studies which can propose models predicting the thermal conductivity if changes in porosity are known. Moreover, the results indicated that the thermal conductivity of a cement material is directly related to the density and inversely related to porosity. Finally, this study showed that a characteristic coefficient can be deduced for two states of material: non-carbonated and carbonated. This coefficient is therefore proper to a specific material and can be used not only for modeling the relationship between porosity and thermal properties but also for other microstructural studies of cement materials.

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The effect of silanes as integral hydrophobic admixture on the physical properties of cement based materials

Journal of Physics Conference Series ◽

10.1088/1742-6596/2069/1/012045 ◽

2021 ◽

Vol 2069 (1) ◽

pp. 012045

Author(s):

K Grabowska ◽

A Wieczorek ◽

D Bednarska ◽

M Koniorczyk

Keyword(s):

Mechanical Properties ◽

Mechanical Strength ◽

Physical Properties ◽

Water Absorption ◽

Cement Mortar ◽

Organosilicon Compounds ◽

Capillary Water ◽

Main Ingredient ◽

Capillary Water Absorption ◽

Cement Based Materials

Abstract The paper explores the possibility of using organosilicon compounds (e.g., poly(dimethylsiloxane) and triethoxyoctylsilane) in commercial admixtures as internal hydrophobization agents for porous cement-based materials. The study involved the cement mortar with five different hydrophobic admixtures. Four of them is based on triethoxyoctylsilane, but with various concentration of the main ingredient, and one of them on poly(dimethylsiloxane). Mechanical properties, capillary water absorption, as well as microstructure were investigated. The organosilicon admixtures efficiently decrease the capillary water absorption even by 81% decreasing mechanical strength of cement mortar at the same time even by 55%. Only one admixture, based on poly(dimethylsiloxane) caused significant changes in microstructure of cement mortar.

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