Properties of Permeable Concrete Substrate Having Dual Pore Structures

Porous concretes with continuous voids have been gaining more interest as an ecological material because of their useful functions such as water permeability and adsorption ability. Especially, to make porous concrete much more environmentalized, micropores play a role of nest for microorganism and germs to live in. So micropore distribution and the size of micropores especially open pores are the key point . In this study, the size and distribution of micropores of porous concrete were effected by the AE agents to the cement pastes and then by the treating types, treating times, treating temperatures, and the vacuum pressure during the treating. And another group specimens were added sodium bicarbonate and alum. And then physical properties were examined, digital microscope was also used to observe the micropores sizes and distributions. Cracks were observed on the cement-aggregate joint when the amount and vacuum pressure increased. And high treating temperature shows no good on the bonding of cement paste and aggregate.

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Distribution and Shape of the Pores in Water Permeable Concrete

Materials Science Forum ◽

10.4028/www.scientific.net/msf.544-545.227 ◽

2007 ◽

Vol 544-545 ◽

pp. 227-230

Author(s):

Z. X. Yang ◽

Jeong Bae Yoon ◽

J.O. Kim ◽

Kyu Hong Hwang ◽

B.S. Jun ◽

...

Keyword(s):

Compressive Strength ◽

Pore Size Distribution ◽

Pore Size ◽

Water Permeability ◽

Type I ◽

Adsorption Ability ◽

Cement Pastes ◽

Size And Shape ◽

Crushed Aggregate ◽

Type C

Porous concretes with continuous voids have been gaining more interest as an ecological material because of their useful functions such as water permeability and adsorption ability. So pore size distribution and the shape of especially open pores are the key point to permeability. In this study, the size and shape of pores of water permeable concrete were primary controlled by the size and shape of aggregates and secondly by the expanding agents to the cement pastes. 2 types of raw coase aggregate, type I and type C which mean fabricated by impact crusher and concrusher, were taken into uses and 3 sizes of aggregate were used, namely 3 to 5mm, 5 to 13 mm, and 13 to 20 mm. The compressive strength was found to be higher when using impact crushed aggregate. And the smaller size of aggregate was used, the higher compressive strength was achieved.

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Hydration Reactions in Cement Pastes Incorporating Fly Ash and Other Pozzolanic Materials

MRS Proceedings ◽

10.1557/proc-86-139 ◽

1986 ◽

Vol 86 ◽

Cited By ~ 6

Author(s):

F. P. Glasser ◽

S. Diamond ◽

D. M. Roy

Keyword(s):

Fly Ash ◽

Physical Properties ◽

Silica Content ◽

Cement Pastes ◽

Blended Cements ◽

Natural Pozzolans ◽

High Calcium ◽

High Silica ◽

Class F Fly Ash

ABSTRACTA model for reactions that occur in hydrating portland cement is now generally well developed. Incorporation of various by-products to form blended cements modifies both the hydration reactions and the physical properties of the resulting pastes. A review of recent progress in understanding the effects of blending agents on these reactions is presented. The blending agents considered are low-calcium (Class F) fly ash, high calcium (Class C) fly ash, blast furnace slag, silica fume, biosilica and natural pozzolans. Effects of the blending agents on physical properties such as rheology are also considered. Particular attention is given to the essential role of alkalies in pore solutions and the beneficial reactions that occur with high silica content blending agents.

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The Adsorption of Superplasticizers on Cement Particles and its Relation with Dispersibility

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.687.449 ◽

2013 ◽

Vol 687 ◽

pp. 449-455

Author(s):

Zi Ming Wang ◽

Ya Li Wang ◽

Ming Zhang Lan

Keyword(s):

Zeta Potential ◽

Cement Paste ◽

Isoelectric Point ◽

Test Results ◽

Cement Pastes ◽

Adsorption Behaviors ◽

Adsorption Amount ◽

The Relationship

The dispersing effect of superplasticizer is closely related to its adsorption behaviors on the surface of cement particles or the hydrates. But the relationship between the adsorption amount of superplasticizer and the fluidity of cement paste seems uncertain. To investigate the relationship between the adsorption amount and the fluidity of cement paste, three groups of cements with designed compositions and C3A mineral were prepared in lab. Four types of superplasticizer were used to measure the adsorption on various cements. The corresponding zeta potential of cement particles with superplasticzers and the fluidity of cement pastes were tested and analyzed. It was found that the adsorption amount of superplasticizer was inversely related to the fluidity of cement paste for a given superplasticizer. The zeta potential of cement particles in the paste was proportional to the adsorption amount of superplasticizer. The adsorption amount of different superplasticizers at the isoelectric point in C3A-H2O system was determined. The meaning of the “adsorption amount” was discussed. The author proposed that the superplasticizer in cement paste should include three parts, and the role of each part was discussed according to test results and analysis.

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SIMULATION OF CEMENT-PASTE SETTING BEHAVIOR BASED ON THE PHYSICAL PROPERTIES OF BLENDED-CEMENT POWDERS

Journal of Green Building ◽

10.3992/1943-4618.14.3.47 ◽

2019 ◽

Vol 14 (3) ◽

pp. 47-61

Author(s):

Yaniv Knop ◽

Alva Peled

Keyword(s):

Physical Properties ◽

Cement Paste ◽

Empirical Model ◽

Linear Regression Analysis ◽

Blended Cement ◽

Cement Pastes ◽

Blended Cements ◽

Linear Behavior ◽

Setting Process ◽

Time Required

In this study, an empirical model was developed to simulate the setting process of cement pastes, with and without limestone. Interestingly, an excellent linear correlation was found between the time required for the cement pastes to reach penetration depths of 0 mm to 40 mm (the setting process) and the physical properties of the powders comprising those pastes. The empirical model was based on this clear, linear behavior, determined by means of linear regression analysis. The developed model offers an easy way to predict and to control the setting history of any cement paste, with and without limestone additive, by simply using the available, measured physical properties of the blended cements with limestone particles of various sizes.

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Role of Superplasticizer Additives Upon Hydration Process of Cement Pastes

Scientific Bulletin of Valahia University - Materials and Mechanics ◽

10.1515/bsmm-2016-0004 ◽

2016 ◽

Vol 14 (11) ◽

pp. 23-26

Author(s):

Nicolae Angelescu ◽

Darius Stanciu ◽

José Barroso de Aguiar ◽

Hakim S. Abdelgader ◽

Vasile Bratu

Keyword(s):

Comparative Analysis ◽

Cement Paste ◽

Hydration Process ◽

X Ray Diffraction ◽

Cement Pastes ◽

Cement Ratio ◽

Water Cement Ratio ◽

X Ray ◽

Thermogravimetry Analysis

Abstract The article presents a comparative analysis on the hydration of cement paste without superplasticizer and water/cement ratio of 0.35 and a cement paste with the same water/cement ratio but has in its composition 2% superplasticizer additive Glenium Sky 526. For characterizing the hydration process of cement paste, both mixtures were subjected to X-ray diffraction and thermogravimetry analysis, at 3, 7, and 28 days passed since the initiation of hydration process.

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Hydration Reactions in Cement Pastes Incorporating Fly Ash and Other Pozzolanic Materials

MRS Proceedings ◽

10.1557/proc-85-167 ◽

1986 ◽

Vol 85 ◽

Cited By ~ 2

Author(s):

F. P. Glasser ◽

S. Diamond ◽

D. M. Roy

Keyword(s):

Fly Ash ◽

Physical Properties ◽

Silica Content ◽

Cement Pastes ◽

Blended Cements ◽

Natural Pozzolans ◽

High Calcium ◽

High Silica ◽

Class F Fly Ash

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Faculty Opinions recommendation of The role of ABA and the transpiration stream in the regulation of the osmotic water permeability of leaf cells.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1004186.27054 ◽

2001 ◽

Author(s):

Walter Kockenberger

Keyword(s):

Water Permeability ◽

Osmotic Water Permeability ◽

Transpiration Stream ◽

Osmotic Water

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Effect of Calcium Nitrate on the Properties of Portland–Limestone Cement-Based Concrete Cured at Low Temperature

Materials ◽

10.3390/ma14071611 ◽

2021 ◽

Vol 14 (7) ◽

pp. 1611

Author(s):

Gintautas Skripkiūnas ◽

Asta Kičaitė ◽

Harald Justnes ◽

Ina Pundienė

Keyword(s):

Compressive Strength ◽

Cement Paste ◽

Setting Time ◽

Calcium Nitrate ◽

Curing Temperature ◽

Hardened Concrete ◽

Cement Pastes ◽

Initial Setting Time ◽

Initial Setting ◽

Early Strength

The effect of calcium nitrate (CN) dosages from 0 to 3% (of cement mass) on the properties of fresh cement paste rheology and hardening processes and on the strength of hardened concrete with two types of limestone-blended composite cements (CEM II A-LL 42.5 R and 42.5 N) at different initial (two-day) curing temperatures (−10 °C to +20 °C) is presented. The rheology results showed that a CN dosage up to 1.5% works as a plasticizing admixture, while higher amounts demonstrate the effect of increasing viscosity. At higher CN content, the viscosity growth in normal early strength (N type) cement pastes is much slower than in high early strength (R type) cement pastes. For both cement-type pastes, shortening the initial and final setting times is more effective when using 3% at +5 °C and 0 °C. At these temperatures, the use of 3% CN reduces the initial setting time for high early strength paste by 7.4 and 5.4 times and for normal early strength cement paste by 3.5 and 3.4 times when compared to a CN-free cement paste. The most efficient use of CN is achieved at −5 °C for compressive strength enlargement; a 1% CN dosage ensures the compressive strength of samples at a −5 °C initial curing temperature, with high early strength cement exceeding 3.5 MPa but being less than the required 3.5 MPa in samples with normal early strength cement.

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