Influences of Ground Limestone Fineness on the Properties of Cement-Based Materials

2012 ◽  
Vol 517 ◽  
pp. 403-410
Author(s):  
Jia Xiao ◽  
Bao Guo Ma ◽  
Rong Zhen Dong ◽  
Cai Yun Xu
Keyword(s):  
Pore Structure ◽  
Mercury Intrusion Porosimetry ◽  
Cement Mortar ◽  
Hardened Cement ◽  
Cement Pastes ◽  
Mercury Intrusion ◽  
Setting Times ◽  
Cement Based Materials ◽  
Hardened Cement Pastes ◽  
Ground Limestone

The effect of ground limestone fineness on the properties and mechanism of cement-based composite materials was investigated. The setting times, fluidity and strength of cement mortar were measured. In order to identify the mechanism effect of ground limestone fineness on the microstructure of the hardened cement pastes, microstructure analyses such as calorimetry analysis and Mercury Intrusion Porosimetry (MIP) were also performed. Experimental results indicated that the setting times are shortened, and the fluidity and strength of cement mortar are improved with the ground limestone fineness increases. The increase of the ground limestone fineness can effectively inhibit the pore structure of hardened paste, which due to mortar and paste samples incorporating replacement levels of ground limestone, and improve the pore structure of hardened paste.

Matlab Image Processing Technique and Application in Pore Structure Characterization of Hardened Cement Pastes

2013 ◽  
Vol 785-786 ◽  
pp. 1374-1379 ◽  
Author(s):  
An Qun Lu ◽  
Shou Zhi Zhang ◽  
Qian Tian
Keyword(s):  
Image Processing ◽  
Pore Structure ◽  
Processing Technique ◽  
Image Processing Technique ◽  
Hardened Cement ◽  
Analysis Method ◽  
Image Analysis Method ◽  
Cement Pastes ◽  
Backscattered Electron ◽  
Hardened Cement Pastes

Based on Matlab image processing technique and backscattered electron image analysis method, a characterization method is set up to make quantitative analysis on pore structure of hardened cement pastes. Adopt Matlab to acquire images, and carry out gradation and binarization processing for them; use the combination method of local threshold segmentation and histogram segmentation to obtain pore structure characteristics. The results showed that evolution law of pore structure of fly ash cement pastes via Matlab image analysis method is similar to the conclusion obtained through BET and DVS. Selecting different angle of backscattered electron images in the same sample, its statistic results are more representative.

Corrosion of Hardened Cement Paste by NH4NO3 and Acetic and Formic Acids

1988 ◽  
Vol 137 ◽  
Author(s):  
Adolf Bajza
Keyword(s):  
Time Use ◽  
Mercury Intrusion Porosimetry ◽  
Total Porosity ◽  
Hardened Cement ◽  
Hardened Cement Paste ◽  
Cement Pastes ◽  
Blended Cements ◽  
Water To Cement Ratio ◽  
Hardened Cement Pastes

AbstractEffects of NH4NO3, CH3COOH and HCOOH solutions on the pore structure and other properties of hardened cement pastes made out of portland, slag, and fly ash cements at different water-to-cement ratios are discussed.Total porosity and the volume of pores detectable by mercury intrusion porosimetry (MIP) increased with increasing water-to-cement ratio, concentration of aggressive solution, and time of immersion. The weight, bulk density, and compressive strenath of the samples decreased at the same time. Use of blended cements did not result in improvement of the long-term durability of the samples. The degradation of the cement pastes increased from NH4NO3 to CH3COOH to HCOOH.

The Effect Of Pore Structure And Cracking On The Permeability Of Concrete

1988 ◽  
Vol 137 ◽  
Author(s):  
Thomas A. Bier ◽  
Darmawan Ludirdja ◽  
J. Francis Young ◽  
Richard L. Berger
Keyword(s):  
Pore Structure ◽  
Pressure Range ◽  
Mercury Intrusion Porosimetry ◽  
Low Pressure ◽  
Hydrated Cement ◽  
Cement Pastes ◽  
Mercury Intrusion

AbstractPermeability measurements have been conducted for mortars, concrete and hydrated cement pastes. The permeability with water as the penetrating medium has been measured in a low pressure range (˜ 0.5 psi) and at higher pressures up to 400 psi. Samples never exposed to drying and oven dried samples (105 °C) have been investigated. Pore structure of the investigated samples has been characterized using mercury intrusion porosimetry.The results are discussed with regard to changes in structure during the experiment due to progressing hydration and healing of cracks.

Pore Structure of Low Porosity DSP Cement Pastes

1988 ◽  
Vol 137 ◽  
Author(s):  
Sara A. Touse ◽  
Thomas A. Bier ◽  
Cheryl A. Knepfler ◽  
J. Francis Young ◽  
Richard L. Berger
Keyword(s):  
Pore Structure ◽  
Silica Fume ◽  
Mercury Intrusion Porosimetry ◽  
Nitrogen Adsorption ◽  
Capillary Porosity ◽  
Cement Pastes ◽  
Mercury Intrusion ◽  
Binding Phase ◽  
Solvent Replacement ◽  
Low Porosity

AbstractThe pore structure of low porosity cement pastes containing varying quantities of silica fume has been examined using mercury intrusion porosimetry (MIP) and nitrogen adsorption (NA) measurements. The water:solid ratio for all DSP pastes studied was 0.18. It was observed that, as for conventional pastes, removal of water by solvent replacement with methanol minimizes changes to the pore structure. Vacuum or oven drying severely reduces specific surface area and obscures important trends.It was found that capillary porosity in excess of 10 nm (100 Å) is essentially absent and that the pore volume measured can be considered an intrinsic part of the binding phase. The influence of silica fume and curing times on pore structure has been measured and the implications of the data will be discussed. Comparisons will be made with conventional cement pastes.

The Influence of Moisture on the Expansion of Macro-Defect-Free Cements

1991 ◽  
Vol 245 ◽  
Author(s):  
H. Igarashi ◽  
T. Takahashi
Keyword(s):  
Image Analysis ◽  
Polyvinyl Alcohol ◽  
Portland Cement ◽  
Pore Structure ◽  
Calcium Hydroxide ◽  
Mercury Intrusion Porosimetry ◽  
Nitrogen Adsorption ◽  
Cement Pastes ◽  
Alcohol Acetate ◽  
Mercury Intrusion

ABSTRACTMDF(Macro-Defect-Free ) cement pastes, which consist of portland cement and polyvinyl alcohol/acetate, were prepared by varying the temperature during pressing and drying operations. We then examined the expansion of MDF cement pastes at various constant humidities. There was a large difference in expansion above 60%R.H. between samples prepared varying temperature at which samples were pressed. Samples pressed at 90 °C showed less expansion than samples pressed at 40 °C.The pore structure of MDF cement pastes before exposure to moisture was measured by nitrogen adsorption, mercury intrusion porosimetry and image analysis. The properties of a matrix containing polyvinyl alcohol/acetate and cemnt hydrates were also investigated by TEM, IR and XPS.There were not large differences in the result of IR and XPS measurement between the MDF cement pastes prepared at various temperatures. Calcium hydroxide crystal, lying perpendicular to cement particles, were often observed only in the MDF cement pastes pressed at 90 °C which occurs by water absorption, seems to be suppressed by calcium hydroxide crystal.

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