scholarly journals Embedded NMR Sensor to Monitor Compressive Strength Development and Pore Size Distribution in Hydrating Concrete

Sensors ◽  
2013 ◽  
Vol 13 (12) ◽  
pp. 15985-15999 ◽  
Author(s):  
Floriberto Díaz-Díaz ◽  
Prisciliano de J. Cano-Barrita ◽  
Bruce Balcom ◽  
Sergio Solís-Nájera ◽  
Alfredo Rodríguez
Keyword(s):  
Compressive Strength ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Strength Development ◽  
Compressive Strength Development

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.

scholarly journals Effect of Internal Pores Formed by a Superabsorbent Polymer on Durability and Drying Shrinkage of Concrete Specimens

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5199
Author(s):  
Il-Sun Kim ◽  
So-Yeong Choi ◽  
Yoon-Suk Choi ◽  
Eun-Ik Yang
Keyword(s):  
Compressive Strength ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Penetration Depth ◽  
Drying Shrinkage ◽  
Chloride Penetration ◽  
Superabsorbent Polymer ◽  
Concrete Mix ◽  
Air Entrained Concrete

In this study, the effect of internal pores formed by a superabsorbent polymer (SAP) was analyzed by evaluating the compressive strength, chloride penetration depth, drying shrinkage, and pore size distribution of SAP-containing concrete, while securing workability using a water-reducing agent (WRA). The experimental results showed that the amount of WRA necessary increased as the amount of SAP added increased, and that the compressive strength was the highest when the SAP content was 1.5% of the concrete mix. Drying shrinkage tended to decrease as the SAP content increased, and it decreased by approximately 31–41% when the SAP content was 2.0% compared to that of the reference mix. The SAP expanded by approximately three times inside concrete, and it was distributed within the internal pores of air-entrained concrete. The optimal SAP content in concrete mix was 1.5%, and an SAP content of 2.0% or higher adversely affected the workability and compressive strength.

Microstructure and Porosity of Metakaolin Blended Cements

1988 ◽  
Vol 137 ◽  
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.

scholarly journals The Influence of Casein Protein Admixture on Pore Size Distribution and Mechanical Properties of Lime-Metakaolin Paste

Buildings ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 530
Author(s):  
Przemysław Brzyski ◽  
Zbigniew Suchorab ◽  
Grzegorz Łagód
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Building Materials ◽  
Total Porosity ◽  
Organic Polymer ◽  
Partial Replacement ◽  
Average Pore

Biopolymers based on proteins are applied in the building materials technology to modify and improve their selected properties. These polymers are designed as natural admixtures that improve the workability of materials. Casein is an example of a protein-based organic polymer. It is a protein obtained from cow’s milk. The paper aimed at investigating the prospects of enhancing the strength properties of a binder prepared on a basis of metakaolin and hydrated lime. The mix was modified with powdered technical casein at 0.5%, 1%, 3%, and 5% as a partial replacement for the binder mix by mass. The study involved investigating the effect of the applied natural admixture on the flexural and compressive strengths, as well as pore size distribution. The average pore diameter decreased in the recipes with casein in the amount of 0.5% and 1%, while it increased when the amount of casein equaled 3% and 5%. Only the 0.5% casein admixture caused a decrease in the total porosity. The results show a clear dependence of the strength parameters on porosity. The admixture of casein significantly increased the flexural strength of the pastes, and decreased the compressive strength. The highest increase in flexural strength (by 205.7%) was caused by the admixture of 0.5% casein, while the greatest decrease in compressive strength (by 28%) was caused by the 3% casein admixture. The flexural strength was enhanced, i.a., due to the improved adhesion and mutual bonding of lime particles, resulting from the application of a sticky admixture. No notable difference was indicated during carbonation by the phenolphthalein test. The lime binder is characterized by a slow setting process and low mechanical strength. The results of the research showed the possibility of improving the flexural strength using small amounts of natural admixture, which may broaden the scope of application of this binder.

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