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.

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.

scholarly journals Study on the Pore Structure Characteristics of Ferronickel-Slag-Mixed Ternary-Blended Cement

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4863
Author(s):  
Won Jung Cho ◽  
Min Jae Kim ◽  
Ji Seok Kim
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Pore Structure ◽  
Mercury Intrusion Porosimetry ◽  
Chloride Transport ◽  
Blended Cement ◽  
Cement Matrix ◽  
X Ray ◽  
Mercury Intrusion ◽  
Ferronickel Slag

Pore structure development in Portland cement, fly ash, or/and ferronickel slag (FNS) was investigated using mercury intrusion porosimetry and X-ray CT tomography. The progress of hydration was observed using X-ray diffraction (XRD) analysis and compressive strength while durability of concrete was monitored by chloride penetration resistance and chloride profiles. Mercury intrusion porosimetry (MIP) results suggested that the blended cement had a higher porosity while lower critical pore size. The major reason to this increased porosity was the formation of meso and micro pores compared to ordinary Portland cement (OPC). In terms of chloride transport, replaced cement, especially ternary-blended cement had higher resistance to chloride transport and exhibited slightly lower development of compressive strength. X-ray CT tomography shows that the influence of pore structure of ternary-blended cement on the ionic transport was strongly related to the pore connectivity of cement matrix.

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.

scholarly journals Pore Size Distribution and Surface Multifractal Dimension by Multicycle Mercury Intrusion Porosimetry of GGBFS and Limestone Powder Blended Concrete

2021 ◽  
Vol 11 (11) ◽  
pp. 4851
Author(s):  
Yury Villagrán-Zaccardi ◽  
Natalia Alderete ◽  
Philip Van den Van den Heede ◽  
Nele De De Belie
Keyword(s):  
Environmental Impact ◽  
Portland Cement ◽  
Pore Structure ◽  
Size Distribution ◽  
Mercury Intrusion Porosimetry ◽  
Pore Wall ◽  
Contact Angles ◽  
Limestone Powder ◽  
Portland Cement Concrete ◽  
Mercury Intrusion

Eco-friendly concrete mixtures make efficient use of constituents with reduced environmental impact to secure durable structures. Ternary mixes containing Portland cement, ground granulated blast-furnace slag (GGBFS) and limestone powder (LP) have demonstrated a good balance between environmental impact, economic cost and technical performance. The pore structure of cement-based materials determines the transport of species; hence its description is a valuable tool for predicting their durability performance. In this paper, textural analysis of the pore structure of Portland cement concrete and GGBFS and limestone powder blended concrete is assessed by multicycle mercury intrusion porosimetry (MIP). Results from three intrusion-extrusion cycles were used for determining pore volume, size distribution and surface multifractal dimension. The hysteresis during the experiments is mainly explained by the combined effects of ink-bottle pores and different contact angles for the intrusion and retraction. The analysis of the surface multifractal dimension of the pore structure showed no significant effects of GGBFS and limestone powder on the pore wall texture of concrete samples. The outcome depicts the advantages of using multiple intrusion-extrusion cycles during MIP experiments, as well as the effect of 35 wt.% GGBFS, 25 wt.% GGBFS + 10 wt.% LP, and 25 wt.% of LP, on concrete pore structure.

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