Influence of Surface Treatment on Pore Structures of Cement-Based Materials

2006 ◽  
Vol 302-303 ◽  
pp. 347-355 ◽  
Author(s):  
Chien Hung Chen ◽  
Ming Chin Ho ◽  
Shaing Hai Yeh ◽  
Ran Huang

The objective of this investigation is to evaluate the effect of surface treatments on cement-based materials, which include mortar and concrete samples. Penetrated sealers and methyl methacrylate (MMA) were used as surface treatment materials. Two concrete mixes (w/c = 0.35, 0.55) were selected and cubic/cylindrical specimens were prepared according to ASTM specifications. The treated specimens have higher compressive strengths than the control specimens. Also, the absorptions and total charge passed of rapid chloride penetration test (RCPT) are lower in the treated specimens. Scanning electronic microscope (SEM) was utilized to estimate the microstructure of the specimens. Denser pore structures and narrower pore-size distribution were observed in SEM micrographs and mercury intrusion porosimetry (MIP) spectrum for the treated specimens, which are correspondent to the macro-observation. The positive effect is most prominent in polymer treated specimens. For higher w/c ratio mix, large capillary pores were filled by most of treatment materials and compressive strength significantly increased, while, for lower w/c ratio mix, polymer and silicate sealer filled in medium capillary pores as indicated by MIP and RCPT results.

2010 ◽  
Vol 168-170 ◽  
pp. 615-618
Author(s):  
Zhi Qin Du ◽  
Wei Sun

The effect of different quantity of air-entraining agent on the impermeability of cement-based materials are studied in this paper. Impermeability test and mercury intrusion porosimetry (MIP) method were used to characterize the impermeability and pore structures. The fractal dimension is used to describe the characteristic of pore structure and calculated by the data of MIP experiment. The result shows that owing to the improvement of pore structure, the impermeability performance of the cement-based composites is noticeably enhanced when air-entraining agent is added with appropriate quantity.


2018 ◽  
Vol 21 (11) ◽  
pp. 1097-1119 ◽  
Author(s):  
Fuyong Wang ◽  
Liang Jiao ◽  
Zhichao Liu ◽  
Xiqun Tan ◽  
Congle Wang ◽  
...  

1986 ◽  
Vol 85 ◽  
Author(s):  
B. K. Marsh ◽  
R. C. Joshi ◽  
A. Balasundaram

ABSTRACTPore structures of portland and blended cement mortars prepared with sea water were assessed by mercury intrusion porosimetry. Comparison is made with similar mortars made with fresh water. Mortars were made using cement containing 0%, 25% or 50% (by volume) of one of two Alberta fly ashes. They were tested after 90 days of continuous immersion in sea water at 5°C or 20° C. Results show that the mortars made with sea water generally contained a much higher volume of fine pores although the porosity was, in some cases, greater than that of mortars made with fresh water. Nevertheless, the volume of larger pores was lower in the mortars made with sea water. The pore structure of the various mortars is discussed in relation to potential durability.


2014 ◽  
Vol 897 ◽  
pp. 176-179
Author(s):  
Ľudovít Krajči ◽  
Ivan Janotka ◽  
Marta Kuliffayova ◽  
Peter Uhlik

The Slovak natural raw material kaolin sand containing 36 wt.% of kaolinite from Vyšný Petrovec deposit was thermally transformed at 650 °C for 1 hour to the metakaolin sand with relevant content of metakaolinite. Behaviour of cement composites having replacement of Portland cement with metakaolin sand including 0; 5; 10 and 15 wt.% of metakaolinite and water to solids ratio of 0.5 cured in water for 28 days and 90 days was studied by thermal analysis, X-ray diffraction analysis and mercury intrusion porosimetry analysis. The study concerned calciumsilica hydrate and calcium aluminate hydrate formation, portlandite dehydroxylation and calcite decarbonation. The influence of curing time and metakaolinite content were estimated. The replacement of Portland cement by metakaolin sand led to positive effect on relevant compressive strengths. The changes in microstructure involved especially reduction in portlandite content and pore structure refinement.


Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4164 ◽  
Author(s):  
Hayeon Kim ◽  
Hyeongmin Son ◽  
Joonho Seo ◽  
H. K. Lee

The present study evaluated the self-healing efficiency and mechanical properties of mortar specimens incorporating a bio-carrier as a self-healing agent. The bio-carrier was produced by immobilizing ureolytic bacteria isolated from seawater in bottom ash, followed by surface coating with cement powder to prevent loss of nutrients during the mixing process. Five types of specimens were prepared with two methods of incorporating bacteria, and were water cured for 28 days. To investigate the healing ratio, the specimens with predefined cracks were treated by applying a wet–dry cycle in three different conditions, i.e., seawater, tap water, and air for 28 days. In addition, a compression test and a mercury intrusion porosimetry analysis of the specimens were performed to evaluate their physico-mechanical properties. The obtained results showed that the specimen incorporating the bio-carrier had higher compressive strength than the specimen incorporating vegetative cells. Furthermore, the highest healing ratio was observed in specimens incorporating the bio-carrier. This phenomenon could be ascribed by the enhanced bacterial viability by the bio-carrier.


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