Characterization of Micro-Pore Structure in Novel Cement Matrices

2014 ◽  
Vol 1712 ◽  
Author(s):  
Seyoon Yoon ◽  
Isabel Galan ◽  
Kemal Celik ◽  
Fredrik P. Glasser ◽  
Mohammed S. Imbabi
Keyword(s):  
Portland Cement ◽  
Pore Structure ◽  
Engineering Properties ◽  
Calcium Sulfoaluminate ◽  
Pore Structures ◽  
Porosity And Permeability ◽  
Experimental Protocols ◽  
Novel Processing ◽  
Main Component

ABSTRACTCalcium sulfoaluminate (CSA) cements are being developed using a novel processing method having as its objective lowering specific CO2 emissions by ∼50% relative to a Portland cement benchmark. We need to be able to measure the properties of the products. Porosity and permeability measurements help define the engineering properties but their quantification is influenced by the choice of experimental protocols. In the present study we used ordinary Portland cement (PC) paste as a benchmark and hydrated ye’elimite, which is a main component of CSA cements, to understand its pore structure. We report on the use of synchrotron-sourced radiation for µCT (Computerized Tomography) and 3D image re-construction of the internal micro-pore structure of PC and ye’elimite-gypsum pastes. As a comparison, porosity and permeability measurements were traditionally obtained using Mercury Intrusion Porosimetry (MIP). The Mori-Tanaka method and the polynomial statistical model were used to analyze the effects of different 3-D micro-pore structures on mechanical properties. The results show that e micro-pore structures differ considerably between PC and ye’elimite pastes and their bulk modulus is significantly affected by the shapes of their micro-pore structures.

Multiscale characterization of pore structure in carbonate formations: Application to the Scurry Area Canyon Reef Operators Committee Unit

2016 ◽  
Vol 4 (2) ◽  
pp. SF165-SF177 ◽  
Author(s):  
Emmanuel Oyewole ◽  
Mehrnoosh Saneifar ◽  
Zoya Heidari
Keyword(s):  
Pore Structure ◽  
Pore Network ◽  
Effective Porosity ◽  
Well Log ◽  
Porosity And Permeability ◽  
Network Properties ◽  
Log Domain ◽  
Carbonate Formations ◽  
Pore Types

Carbonate formations consist of a wide range of pore types with different shapes, pore-throat sizes, and varying levels of pore-network connectivity. Such heterogeneous pore-network properties affect the fluid flow in the formation. However, characterizing pore-network properties (e.g., effective porosity and permeability) in carbonate formations is challenging due to the heterogeneity at different scales and complex pore structure of carbonate rocks. We have developed an integrated technique for multiscale characterization of carbonate pore structure based on mercury injection capillary pressure (MICP) measurements, X-ray micro-computed tomography (micro-CT) 3D rock images, and well logs. We have determined pore types based on the pore-throat radius distributions obtained from MICP measurements. We developed a new method for improved assessment of effective porosity and permeability in the well-log domain using pore-scale numerical simulations of fluid flow and electric current flow in 3D micro-CT core images obtained in each pore type. Finally, we conducted petrophysical rock classification based on the depth-by-depth estimates of effective porosity, permeability, volumetric concentrations of minerals, and pore types using an unsupervised artificial neural network. We have successfully applied the proposed technique to three wells in the Scurry Area Canyon Reef Operators Committee (SACROC ) Unit. Our results find that electrical resistivity measurements can be used for reliable characterization of pore structure and assessment of effective porosity and permeability in carbonate formations. The estimates of permeability in the well-log domain were cross-validated using the available core measurements. We have observed a 34% improvement in relative errors in well-log-based estimates of permeability, as compared with the core-based porosity-permeability models.

scholarly journals Quantitative Characterization of Heterogeneity in Different Reservoir Spaces of Low-Permeability Sandstone Reservoirs and Its Influence on Physical Properties

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Fengjuan Dong ◽  
Na Liu ◽  
Zhen Sun ◽  
Xiaolong Wei ◽  
Haonan Wang ◽  
...  
Keyword(s):  
Fractal Dimension ◽  
Pore Structure ◽  
Fractal Theory ◽  
Fractal Dimensions ◽  
Low Permeability ◽  
Quantitative Characterization ◽  
Average Value ◽  
Porosity And Permeability ◽  
Sandstone Reservoirs

The complex pore structure of low-permeability sandstone reservoir makes it difficult to characterize the heterogeneity of pore throat. Taking the reservoir of Sanjianfang formation in QL oilfield as an example, the fractal dimension of different storage spaces is calculated by using fractal theory based on casting thin section, scanning electron microscope, and high-pressure mercury injection, and the correlation between porosity, permeability, and contribution of different storage space permeabilities is analyzed. The results show that the reservoir of Sanjianfang formation in QL oilfield mainly develops small pores, fine pores, and micropores, and the fractal dimension of micropore structure is between 2.6044 and 2.9982, with an average value of 2.8316. The more complex the pore structure is, the stronger the microheterogeneity is. The higher the fractal dimension, the more complex the pore structure and the smaller the porosity and permeability. The fractal dimensions of small pores, fine pores, and micropores increase successively with the decrease in pore radius, and the microstructure heterogeneity of large pores is weaker than that of small pores. It provides a theoretical basis for the exploration and development of low-permeability sandstone reservoirs.

Relation Between Strength, Pore Structure and Associated Properties of Slag-Containing Cementitious Materials

1984 ◽  
Vol 42 ◽  
Author(s):  
Della M. Roy ◽  
G. M. Idorn
Keyword(s):  
Blast Furnace ◽  
Portland Cement ◽  
Pore Structure ◽  
Cement Paste ◽  
Blast Furnace Slag ◽  
Cementitious Materials ◽  
Granulated Blast Furnace Slag ◽  
Pore Structures ◽  
Furnace Slag

AbstractSubstantial increases of the strength of cement paste and mortars may be obtained in conventional processing by optimizing the materials components, the rheology and the curing, and thereby improving the microstructures. Cementitious materials with high proportions of granulated blast-furnace slag have been investigated. Higher strengths of ASTM C 109 mortars were obtained with 40 to 65% substitution of portland cement by slag, than with ordinary mix compositions and processing.For one set of mixtures, 28 day strengths ≥ 100 MPa (some as high as 240 MPa) were consistently attained after curing at temperatures ranging from 27 to 250°C. The slag substitutions developed finer pore structures as revealed by intrusion porosimetry measurements, than those with pure portland cement. This is believed to be a major reason for their enhanced durability. At each stage from 3 to 28 days, increase of curing temperatures from 27 to 90°C decreased porosity and increased the strength, reflecting an increased maturity.Implications for practice and suggestions for further work are discussed.

scholarly journals Influence of Different Alkali Sulfates on the Shrinkage, Hydration, Pore Structure, Fractal Dimension and Microstructure of Low-Heat Portland Cement, Medium-Heat Portland Cement and Ordinary Portland Cement

2021 ◽  
Vol 5 (3) ◽  
pp. 79
Author(s):  
Yang Li ◽  
Hui Zhang ◽  
Minghui Huang ◽  
Haibo Yin ◽  
Ke Jiang ◽  
...  
Keyword(s):  
Fractal Dimension ◽  
Portland Cement ◽  
Pore Structure ◽  
Ordinary Portland Cement ◽  
Autogenous Shrinkage ◽  
Drying Shrinkage ◽  
Crystal Forms ◽  
Pore Structures ◽  
Cement Based Materials ◽  
Mineral Compositions

In cement-based materials, alkalis mainly exist in the form of different alkali sulfates. In this study, the impacts of different alkali sulfates on the shrinkage, hydration, pore structure, fractal dimension and microstructure of low-heat Portland cement (LHPC), medium-heat Portland cement (MHPC) and ordinary Portland cement (OPC) are investigated. The results indicate that alkali sulfates magnify the autogenous shrinkage and drying shrinkage of cement-based materials with different mineral compositions, which are mainly related to different pore structures and hydration processes. LHPC has the lowest shrinkage. Otherwise, the effect of alkali sulfates on the autogenous shrinkage is more profound than that of drying shrinkage. Compared with the pore size distribution, the fractal dimension can better characterize the shrinkage properties of cement-based materials. It is noted that the contribution of K2SO4 (K alkali) to the promotion effect of shrinkage on cement-based materials is more significant than that of Na2SO4 (Na alkali), which cannot be ignored. The microstructure investigation of different cement-based materials by means of nuclear magnetic resonance (NMR), mercury intrusion porosimetry (MIP) and scanning electron microscope (SEM) shows that this effect may be related to the different pore structures, crystal forms and morphologies of hydration products of cement-based materials.

scholarly journals The Porosity And Pore Structure Of Hydrated Portland Cement Paste

1988 ◽  
Vol 137 ◽  
Author(s):  
R. F. Feldman
Keyword(s):  
Portland Cement ◽  
Pore Structure ◽  
Porous Materials ◽  
Surface Area ◽  
Water Vapour ◽  
Cement Paste ◽  
Mercury Porosimetry ◽  
Pore Structures ◽  
Portland Cement Paste

Pore structure and the surface area of the pores are the most important characteristics controlling the properties of porous materials. Many techniques, based largely on nitrogen or water vapour isotherms or mercury porosimetry, have been used to determine the pore structure of solids. Values obtained from these methods have been relatively reliable for materials with pore structures that remain stable on removal or addition of water.

scholarly journals Influence of MgO on the Hydration and Shrinkage Behavior of Low Heat Portland Cement-Based Materials via Pore Structural and Fractal Analysis

2022 ◽  
Vol 6 (1) ◽  
pp. 40
Author(s):  
Lei Wang ◽  
Xiao Lu ◽  
Lisheng Liu ◽  
Jie Xiao ◽  
Ge Zhang ◽  
...  
Keyword(s):  
Fractal Dimension ◽  
Portland Cement ◽  
Pore Structure ◽  
Fractal Analysis ◽  
Concrete Structures ◽  
Mass Concrete ◽  
Pore Structures ◽  
Cement Based Materials ◽  
Induction Stage ◽  
Shrinkage Behavior

Currently, low heat Portland (LHP) cement is widely used in mass concrete structures. The magnesia expansion agent (MgO) can be adopted to reduce the shrinkage of conventional Portland cement-based materials, but very few studies can be found that investigate the influence of MgO on the properties of LHP cement-based materials. In this study, the influences of two types of MgO on the hydration, as well as the shrinkage behavior of LHP cement-based materials, were studied via pore structural and fractal analysis. The results indicate: (1) The addition of reactive MgO (with a reactivity of 50 s and shortened as M50 thereafter) not only extends the induction stage of LHP cement by about 1–2 h, but also slightly increases the hydration heat. In contrast, the addition of weak reactive MgO (with a reactivity of 300 s and shortened as M300 thereafter) could not prolong the induction stage of LHP cement. (2) The addition of 4 wt.%–8 wt.% MgO (by weight of binder) lowers the mechanical property of LHP concrete. Higher dosages of MgO and stronger reactivity lead to a larger reduction in mechanical properties at all of the hydration times studied. M300 favors the strength improvement of LHP concrete at later ages. (3) M50 effectively compensates the shrinkage of LHP concrete at a much earlier time than M300, whereas M300 compensates the long-term shrinkage more effectively than M50. Thus, M300 with an optimal dosage of 8 wt.% is suggested to be applied in mass LHP concrete structures. (4) The addition of M50 obviously refines the pore structures of LHP concrete at 7 days, whereas M300 starts to refine the pore structure at around 60 days. At 360 days, the concretes containing M300 exhibits much finer pore structures than those containing M50. (5) Fractal dimension is closely correlated with the pore structure of LHP concrete. Both pore structure and fractal dimension exhibit weak (or no) correlations with shrinkage of LHP concrete.

Analysis of the pore structure of adsorbents and its characterization by a numerical method

1984 ◽  
Vol 49 (12) ◽  
pp. 2721-2738 ◽  
Author(s):  
Ondřej Kadlec ◽  
Jerzy Choma ◽  
Helena Jankowska ◽  
Andrzej Swiatkowski
Keyword(s):  
Distribution Function ◽  
Pore Structure ◽  
Numerical Method ◽  
Active Carbon ◽  
Numerical Evaluation ◽  
Suggested Algorithm

This paper describes the algorithm of numerical evaluation of the parameters of the pore structure of adsorbents ( the micro, mezo and macropores). The structure of individual types of pores is described with the equation proposed by one of the present authors and giving the total distribution function of the pores with respect to their radii. The reliability of the suggested algorithm was verified in a number of calculations using a specially developed program. The results of the analysis and characterization of three different specimens of active carbon are shown as an example.

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