Pore Structure, Permeability, And Chloride Diffusion In Fly Ash-And Slag-Containing Pastes And Mortars

1988 ◽  
Vol 137 ◽  
Author(s):  
R. I. A. Malek ◽  
D. M. Roy ◽  
Y. Fang
Keyword(s):  
Chloride Diffusion ◽  
Fly Ashes ◽  
Chloride Permeability ◽  
Cement Pastes ◽  
Granulated Blast Furnace Slag ◽  
Transport Of Ions ◽  
Diffusion Rates ◽  
Different Sources ◽  
Limiting Value

AbstractThe transport of ions through cement pastes and mortars with variable contents of fly ashes and granulated blast-furnace slag from different sources and with variable composition has been investigated. The research included the determination of chloride diffusion rate and chloride permeability in relation to microstructure development. The median pore size generally was much diminished in mature blended material compared with Portland cement (PC) pastes and mortars. It appears that, at the same age, a finer microstructure is generally developed in blended specimens compared to PC specimens. Also, it was found that the microstructure approaches a limiting value at longer ages of hydration. That limiting value may be reached at earlier ages with the blends. The chloride diffusion rates and permeabilities in the blends were significantly lower than PC mixes. A comparison between the blends containing fly ashes and those containing slag was made.

Pore Structure, Permeability, and Chloride Diffusion in Fly Ash-and Slag-Containing Pastes and Mortars

1988 ◽  
Vol 136 ◽  
Author(s):  
R. I. A. Malek ◽  
D. M. Roy ◽  
Y. Fang
Keyword(s):  
Chloride Diffusion ◽  
Fly Ashes ◽  
Chloride Permeability ◽  
Cement Pastes ◽  
Granulated Blast Furnace Slag ◽  
Transport Of Ions ◽  
Diffusion Rates ◽  
Different Sources ◽  
Limiting Value

ABSTRACTThe transport of ions through cement pastes and mortars with variable contents of fly ashes and granulated blast-furnace slag from different sources and with variable composition has been investigated. The research included the determination of chloride diffusion rate and chloride permeability in relation to microstructure development. The median pore size generally was much diminished in mature blended material compared with Portland cement (PC) pastes and mortars. It appears that, at the same age, a finer microstructure is generally developed in blended specimens compared to PC specimens. Also, it was found that the microstructure approaches a limiting value at longer ages of hydration. That limiting value may be reached at earlier ages with the blends. The chloride diffusion rates and permeabilities in the blends were significantly lower than PC mixes. A comparison between the blends containing fly ashes and those containing slag was made.

Relationships Between Permeability, Porosity, Diffusion And Microstructure Of Cement Pastes, Mortar, And Concrete At Different Temperatures

1988 ◽  
Vol 137 ◽  
Author(s):  
Della M. Roy
Keyword(s):  
Pore Structure ◽  
Elevated Temperatures ◽  
Mercury Porosimetry ◽  
Blended Cement ◽  
Ionic Species ◽  
Chloride Diffusion ◽  
Concrete Durability ◽  
Chloride Permeability ◽  
Cement Pastes ◽  
Blended Cements

AbstractPermeabilities to water and diffusion of ionic species in cementitious grouts, pastes and mortars are important keys to concrete durability. Investigations have been made of numerous materials containing portland and blended cements, and those with fine-grained filler, at room temperature and after prolonged curing at several elevated temperatures up to 90°C. These constitute part of studies of fundamental material relationships performed in order to address the question of long-term durability. In general, the permeabilities of the materials have been found to be low [many <10−8 Darcy (10−13 m·s−1)] after curing for 28 days or longer at temperatures up to 60°C. The results obtained at 90°C are somewhat more complex. In some sets of studies of blended cement pastes with w/c varying from 0.30 to 0.60 and cured at temperatures up to 90°C the more open-pore structure (at the elevated temperature and higher w/c) as evident from SEM microstructural studies as well as mercury porosimetry are generally correlated also with a higher permeability to liquid. The degree of bonding and permeability evident in paste or mortar/rock interfacial studies present somewhat more conflicting results. The bond strength (tensile mode) has been shown to be improved in some materials with increased temperature. The results of permeability studies of paste/rock couples show examples with similar low permeabilities, and some with increased permeability with temperature.Ionic diffusion studies also bring important bearing to understanding the effect of pore structure. The best interrelationships between chloride diffusion and pore structure appear to relate diffusion rate to median pore size. Similar results were found with “chloride permeability” test.

Research on Slaked Magnesium Slag as a Raw Material and Blend for Portland Cement

2011 ◽  
Vol 335-336 ◽  
pp. 1246-1249 ◽  
Author(s):  
Ji Wei Cai ◽  
Guang Liang Gao ◽  
Rui Ying Bai ◽  
Feng Lu ◽  
Ling Li
Keyword(s):  
Portland Cement ◽  
Raw Material ◽  
Dust Pollution ◽  
Binary Blends ◽  
Cement Pastes ◽  
Magnesium Metal ◽  
Granulated Blast Furnace Slag ◽  
Furnace Slag

The magnesium slag is discarded from production of magnesium metal from dolomite. However the magnesium slag is slaked in some factories by means of sprinkling water to prevent from dust pollution. The possibility of slaked magnesium slag (SMS) to play a role of raw material and blend for portland cement was investigated by experiments of raw mix preparation, clinker calcining and property determination of cement pastes and mortars. The results revealed that SMS was still reactive. The raw mix with SMS was of excellent burnability that would contribute to energy saving. As a raw material, SMS can be used for calcining clinker of good quality; and as a blend it is suitable for production of ordinary portland cements. Because the magnesium slag is slaked, SMS has no problem on soundness. Higher strength of cement can be obtained in form of binary blends consisting of SMS and ground granulated blast-furnace slag or fly ash.

Effect of ground granulated blast funrnace slag and fly ash on strength, permeability, and under-water abrasion of fine-grained concrete

2020 ◽  
Vol 71 (7) ◽  
pp. 775-788
Author(s):  
Quyet Truong Van ◽  
Sang Nguyen Thanh
Keyword(s):  
Fly Ash ◽  
Concrete Strength ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Chloride Permeability ◽  
Cement Replacement ◽  
Fine Grained ◽  
Granulated Blast Furnace Slag ◽  
Compressive Strength Test ◽  
Economic Ground

The utilisation of supplementary cementitious materials (SCMs) is widespread in the concrete industry because of the performance benefits and economic. Ground granulated blast furnace slag (GGBFS) and fly ash (FA) have been used as the SCMs in concrete for reducing the weight of cement and improving durability properties. In this study, GGBFS at different cement replacement ratios of 0%, 20%, 40% and 60% by weight were used in fine-grained concrete. The ternary binders containing GGBFS and FA at cement replacement ratio of 60% by weight have also evaluated. Flexural and compressive strength test, rapid chloride permeability test and under-water abrasion test were performed. Experimental results show that the increase in concrete strength with GGBFS contents from 20% to 40% but at a higher period of maturity (56 days and more). The chloride permeability the under-water abrasion reduced with the increasing cement replacement by GGBFS or a combination of GGBFS and FA

Development of a micro-mechanical model for the determination of damage properties of cement pastes

2020 ◽  
Vol 261 ◽  
pp. 120514 ◽  
Author(s):  
Abderrahmane Rhardane ◽  
Frédéric Grondin ◽  
Syed Yasir Alam
Keyword(s):  
Mechanical Model ◽  
Cement Pastes

Determination of diffusion rates in acrylamide-based photopolymer material

2006 ◽  
Author(s):  
C. E. Close ◽  
M. R. Gleeson ◽  
J. V. Kelly ◽  
F. T. O'Neill ◽  
D. Mooney ◽  
...  
Keyword(s):  
Diffusion Rates

scholarly journals Comparative Study of Strength and Corrosion Resistant Properties of Plain and Blended Cement Concrete Types

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Velu Saraswathy ◽  
Subbiah Karthick ◽  
Han Seung Lee ◽  
Seung-Jun Kwon ◽  
Hyun-Min Yang
Keyword(s):  
Water Absorption ◽  
Corrosion Behaviour ◽  
Blended Cement ◽  
Effective Porosity ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
Chloride Permeability ◽  
Corrosion Resistant ◽  
Lower Corrosion Rate ◽  
Portland Slag Cement

The relative performances of mechanical, permeability, and corrosion resistance properties of different concrete types were compared. Concrete types were made from ordinary Portland cement (OPC), Portland pozzolana cement (PPC), and Portland slag cement (PSC). Compressive strength test, effective porosity test, coefficient of water absorption, short-term accelerated impressed voltage test, and rapid chloride permeability test (RCPT) were conducted on M30 and M40 grades of concrete designed with OPC, PPC, and PSC cements for 28- and 90-day cured concrete types. Long-term studies such as microcell and electrochemical evaluation were carried out to understand the corrosion behaviour of rebar embedded in different concrete types. Better corrosion resistant properties were observed for PSC concrete by showing a minimum current flow, lowest free chloride contents, and lesser porosity. Besides, PSC concrete has shown less coefficient of water absorption, chloride diffusion coefficient (CDC), and lower corrosion rate and thereby the time taken for initiation of crack extended.

scholarly journals The shrinkage of soils

1917 ◽  
Vol 8 (3) ◽  
pp. 312-330 ◽  
Author(s):  
H. A. Tempany
Keyword(s):  
Linear Relationship ◽  
Pore Space ◽  
Linear Shrinkage ◽  
Fine Silt ◽  
Leeward Islands ◽  
Physical Composition ◽  
Colloidal Clay ◽  
Internal Pore ◽  
Limiting Value

1. By determination of the internal pore space in blocks of soils and comparison with the observed value for the linear shrinkage it is found that a linear relationship appears to exist between the two values.2. By extrapolating the curve thus obtained an approximation for the limiting value of the shrinkage in the case of pure colloidal clay is arrived at amounting to approximately 23 per cent.3. On this assumption it becomes possible to calculate the approximate content of colloidal material in any soil from a knowledge of the linear shrinkage.4. Results are adduced, showing the values obtained for the shrinkage in the case of separated fine silt and clay fractions in the case of two soils of known shrinkage and physical composition, and compared with the values calculated from previous assumptions.5. The results of the calculation of the content of colloidal clay in the foregoing manner in the case of 16 Leeward Islands soils are appended.

Calorimetric determination of the effect of additives on cement hydration process

2013 ◽  
Vol 67 (2) ◽  
Author(s):  
Pavel Šiler ◽  
Josef Krátký ◽  
Iva Kolářová ◽  
Jaromír Havlica ◽  
Jiří Brandštetr
Keyword(s):  
Portland Cement ◽  
Silica Fume ◽  
Maximum Temperature ◽  
Granulated Blast Furnace Slag ◽  
Mineral Components ◽  
Maximum Temperatures ◽  
The Impact ◽  
Furnace Slag ◽  
Calorimetric Determination

AbstractPossibilities of a multicell isoperibolic-semiadiabatic calorimeter application for the measurement of hydration heat and maximum temperature reached in mixtures of various compositions during their setting and early stages of hardening are presented. Measurements were aimed to determine the impact of selected components’ content on the course of ordinary Portland cement (OPC) hydration. The following components were selected for the determination of the hydration behaviour in mixtures: very finely ground granulated blast furnace slag (GBFS), silica fume (microsilica, SF), finely ground quartz sand (FGQ), and calcined bauxite (CB). A commercial polycarboxylate type superplasticizer was also added to the selected mixtures. All maximum temperatures measured for selected mineral components were lower than that reached for cement. The maximum temperature increased with the decreasing amount of components in the mixture for all components except for silica fume. For all components, except for CB, the values of total released heat were higher than those for pure Portland cement samples.

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