scholarly journals Water Absorption Properties of Cement Pastes: Experimental and Modelling Inspections

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Ludovica Casnedi ◽  
Ombretta Cocco ◽  
Paola Meloni ◽  
Giorgio Pia
Keyword(s):  
Pore Size Distribution ◽  
Water Absorption ◽  
Pore Size ◽  
Size Distribution ◽  
Cement Pastes ◽  
Water Absorption Coefficient ◽  
Proposed Model ◽  
Porous Microstructure ◽  
Base Units ◽  
Good Agreement

An intermingled fractal units’ model is shown in order to simulate pore microstructures as pore fraction and pore size distribution. This model is aimed at predicting capillary water absorption coefficient and sorptivity values in cement pastes. The results obtained are in good agreement with the experimental ones. For validating this model, a comparison with other procedures has been shown. It is possible to establish that the newly proposed method matches better with the experimental results. That is probably due to the fact that pore size distribution has been considered as a whole. Moreover, even though the proposed model is based on fractal base units, it is able to simulate and predict different properties as well as nonfractal porous microstructure.

scholarly journals EARLY AGE POROSITY AND PORE SIZE DISTRIBUTION OF CEMENT PASTE WITH FLUE GAS DESULPHURISATION (FGD) WASTE

2013 ◽  
Vol 19 (5) ◽  
pp. 622-627 ◽  
Author(s):  
Jamal M. Khatib ◽  
Pritpal S. Mangat ◽  
Lee Wright
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Cement Paste ◽  
Flue Gas ◽  
Early Stage ◽  
Early Age ◽  
Cement Pastes ◽  
Binder Ratio ◽  
Water To Binder Ratio

This paper is part of a wide-ranging investigation on the use of flue gas desulphurisation (FGD) waste in cement-based materials. It reports the results on the porosity and pore size distribution of cement paste containing varying amounts of simulated FGD waste. The water to binder ratio was 0.5. The binder consists of cement and simulated FGD. The FGD is a combination of fly ash and gypsum ranging from 0% to 100%. Cement in the pastes was partially replaced with 25% FGD (by weight). The porosity and pore size distribution of cement pastes was determined during the early stage of hydration. Increasing the amount of gypsum does not increase the pore volume. However, increasing the amount of gypsum in the paste leads to an increase in the threshold diameter and a decrease in the percentage of small pores in the paste, both indicating a coarser pore structure. The results of this investigation were compared with data at longer curing periods.

Microstructure and Porosity of Metakaolin Blended Cements

1988 ◽  
Vol 136 ◽  
Author(s):  
P. Bredy ◽  
M. Chabannet ◽  
J. Pera
Keyword(s):  
Compressive Strength ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Hydrated Cement ◽  
Cement Pastes ◽  
Blended Cements ◽  
Mercury Intrusion ◽  
Pozzolanic Cement

ABSTRACTFive compositions with 10% to 50% metakaolin for cement substitution were studied. The rate of hydration was studied from the compressive strength after up to 6 months of curing and from the hydrates formed (DTA-XRD). The metakaolin addition considerably reduced portlandite content in the hydrated cement and contributed to the formation of hydrated gehlenite which is not present in OPC paste. The microstructure study (SEM) shows that pozzolanic cement pastes were less crystallized than plain pastes. Mercury intrusion was used to measure porosity of hydrated cement pastes. The porosity with blended cements was higher than that with OPC, except for 10 and 20% metakaolin substitution. Evolution of the pore size distribution was studied: the pozzolanic pastes enhance small diameters.

PORE-SIZE DISTRIBUTION IN BLENDED CEMENT PASTES USING NMR TECHNIQUES

2007 ◽  
pp. 583-590
Author(s):  
M. Katsioti ◽  
M.S. Katsioti ◽  
M. Fardi ◽  
G. Papavassiliou ◽  
J. Marino
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Blended Cement ◽  
Cement Pastes ◽  
Nmr Techniques

scholarly journals Effect of natural weathering on water absorption and pore size distribution in thermally modified wood determined by nuclear magnetic resonance

Cellulose ◽  
2020 ◽  
Vol 27 (8) ◽  
pp. 4235-4247 ◽  
Author(s):  
Chenyang Cai ◽  
Muhammad Asadullah Javed ◽  
Sanna Komulainen ◽  
Ville-Veikko Telkki ◽  
Antti Haapala ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Pore Size Distribution ◽  
Water Absorption ◽  
Pore Size ◽  
Size Distribution ◽  
Natural Weathering ◽  
Thermally Modified Wood ◽  
Modified Wood ◽  
Nuclear Magnetic

scholarly journals Nuclear magnetic resonance analysis of water absorption characteristics and dynamic changes in pore size distribution of wood-plastic composites

BioResources ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. 4064-4080
Author(s):  
Qiang Jin ◽  
Lin Zhu ◽  
Di Hu ◽  
Chunxia He ◽  
Li Li
Keyword(s):  
Pore Size Distribution ◽  
Water Absorption ◽  
Pore Size ◽  
Size Distribution ◽  
Immersion Time ◽  
Dynamic Changes ◽  
Slag Powder ◽  
Low Field ◽  
Plastic Composites ◽  
Absorption Characteristics

Low-field nuclear magnetic resonance (NMR) technology was used to perform the experiments of transverse relaxation time (T2), pore size distribution, and water absorption rate for wood-plastic composites (WPC) with different contents of added slag powder, exploring the water movement and the dynamic changes of pore size during the moisture absorption process of the material under immersion condition. The experimental results were as follows: (1) According to the T2 of H proton and its inversion pattern, the measured porosity had a relatively small difference from that of the weighing method. (2) The pore size distribution graph showed the following: (i) when the immersion time of composite materials was different, the changing law of volume of pores with different radius was different.; (ii) when the material’s immersion time was greater than 216 h, the pore radius and its distribution characteristics showed large differences; (iii) slag powder changed the pore structure of the WPC but did not change the water absorption characteristics of the wheat straw. (3) The changes of water absorption and expansion rate showed that the slag powder changed the time for the materials’ pores to absorb water until saturation and reduced the water absorption and expansion rate. The measurement results were consistent with changing trend in the pore size obtained by low-field NMR relaxometry.

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