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.

Shrinkage of Blended Cement Pastes with Mineral Additions

2013 ◽  
Vol 539 ◽  
pp. 55-59
Author(s):  
Yi Chen ◽  
Wu Yao ◽  
Dan Jin
Keyword(s):  
Fly Ash ◽  
Silica Fume ◽  
Cement Paste ◽  
Mercury Intrusion Porosimetry ◽  
Construction Materials ◽  
Blended Cement ◽  
Cement Pastes ◽  
Mercury Intrusion ◽  
Mineral Additions ◽  
By Products

Mineral additions such as fly ash and silica fume are industrial by products, and play an important role in properties improvement for construction materials. In this work, the shrinkage of cement paste blended with fly ash and silica fume by different substitute ratio was studied. Pore structures of specimens at different ages were determined by mercury intrusion porosimetry (MIP) and shrinkage deformation was measured by standard shrinkage tests. The effects of mineral addtions on shrinkage were discussed. The results show that the fly ash was significantly effective on shrinkage at early ages. Based on the research, several suitable advices were offered to optimize the performances of materials and reduce the shrinkage.

Pore Structure of Hydrated Portland Cement Measured by Nitrogen Sorption and Mercury Intrusion Porosimetry

1986 ◽  
Vol 85 ◽  
Author(s):  
Will Hansen ◽  
Jamal Almudaiheem
Keyword(s):  
Portland Cement ◽  
Pore Structure ◽  
Pore Diameter ◽  
Mercury Intrusion Porosimetry ◽  
Capillary Condensation ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Mercury Intrusion ◽  
Nitrogen Sorption ◽  
Solvent Replacement

ABSTRACTThe pore structure (i.e. surface area, pore size distribution and pore volume) of well-hydrated portland cement pastes of water-cement ratios 0.4, 0.6, and 0.75 were investigated by the nitrogen sorption and mercury intrusion porosimetry (MIP) techniques. The effect of solvent replacement by methanol on the pore structure was studied as well. It was concluded that the solvent replacement drying procedure preserves the original pore structure of hydrated cement because the calculated and measured bulk densities of the different water-cement ratio systems investigated were in excellent agreement. Capillary condensation analysis was used to estimate the volume of capillary pores smaller than 4 nm in pore diameter for the 0.6 and 0.75 water-cement ratio pastes. The 0.4 water-cement ratio paste has pores smaller than can be determined from capillary condensation analysis. The volume of pores smaller than 4 nm was estimated from volume-thickness (V-t) analysis. For the three systems investigated, the volume of pores greater than 4 nm was obtained by MIP. For solvent-replaced pastes that showed capillary condensation according to V-t analysis, excellent agreement was obtained between the nitrogen sorption and MIP techniques in the pore diameter range of 4 nm to 30 nm.

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.

Microstructure of High Strength Concrete Mercury Intrusion Porosimetry and Thermogravimetry Analysis

2011 ◽  
Vol 243-249 ◽  
pp. 3781-3786 ◽  
Author(s):  
Iqbal Khan Mohammad
Keyword(s):  
Fly Ash ◽  
Pore Structure ◽  
Calcium Hydroxide ◽  
Silica Fume ◽  
High Strength Concrete ◽  
Mercury Intrusion Porosimetry ◽  
High Strength ◽  
Thermogravimetry Analysis ◽  
Mercury Intrusion ◽  
Strength Concrete

Microstructural properties such as pore structure and hydration play a decisive role in determining the properties of a concrete. This paper presents the investigation on pore structure and hydration process of high strength concrete. Pore structure study was conducted using mercury intrusion porosimetry and hydration progress was monitored using thermogravimetry analysis on various blended combinations of cementitious materials incorporating fly ash and silica fume as partial cement replacement. It was found that silica fume refined the pore structure efficiently and reduced the calcium hydroxide content as early as 1 day. All ternary blended systems containing fly ash and silica fume exhibited lower calcium hydroxide content and refined pore structure in comparison to their respective blended pastes.

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.

Microstructure and Pore Systems Development of Ternary Gypsum-Based Mortars

2018 ◽  
Vol 760 ◽  
pp. 67-72
Author(s):  
Magdaléna Doleželová ◽  
Jitka Krejsová ◽  
Lenka Scheinherrová ◽  
Petr Svora ◽  
Alena Vimmrová
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Pore Structure ◽  
Silica Fume ◽  
Mercury Intrusion Porosimetry ◽  
Hydrated Lime ◽  
Systems Development ◽  
Elementary Composition ◽  
Mercury Intrusion ◽  
Scanning Electron

Paper deals with ternary gypsum-based mortars with higher resistance against water, prepared from gypsum, hydrated lime, several pozzolans (crushed ceramic, silica fume, granulated blast slag) and sand. The samples were stored in the water and the pore systems development in time was studied by mercury intrusion porosimetry. The change of pore structure in samples with pozzolans were observed, the size of pores shifted to the smaller pores during tested period. The elementary composition and microstructure of all materials were also studied by scanning electron microscopy (SEM).

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