Effect of Low Atmospheric Pressure on Air Entrainment in Cement-Based Materials: An On-Site Experimental Study at Different Elevations
The efficiency and stability of air entrainment in concrete are sometimes found to be weaker at higher elevation. This phenomenon was attributed to the low atmospheric pressure by many researchers, however, the level of influence of atmospheric pressure on concrete air content dramatically varied am...
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MDPI AG
2020-09-01
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| Online Access: | https://www.mdpi.com/1996-1944/13/18/3975 |
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| author | Xin Chen Xu Liu Bo Tian Yong Ge Lihui Li |
| author_facet | Xin Chen Xu Liu Bo Tian Yong Ge Lihui Li |
| author_sort | Xin Chen |
| collection | DOAJ |
| description | The efficiency and stability of air entrainment in concrete are sometimes found to be weaker at higher elevation. This phenomenon was attributed to the low atmospheric pressure by many researchers, however, the level of influence of atmospheric pressure on concrete air content dramatically varied among different studies. In order to clarify the effect of low atmospheric pressure on air entrainment in cement-based materials, an on-site experimental study was conducted with a rigorous control of irrelevant variables. The study focused on the air-entraining efficiency in cement paste, mortar, and concrete prepared in both low and standard atmospheric pressures. The air bubble stability in fresh mortar and air void characteristics of hardened mortar in different atmospheric pressures were also included. In the study, little effect of low atmospheric pressure on the air-entraining efficiency and air bubble stability in mortar with studied air-entraining agents (AEAs) was found. The air void characteristics were found to be similar between mortar with SJ-2 or 303R type AEAs prepared in different atmospheric pressures. Concrete with either SJ-2 or 303R type AEA prepared in low atmospheric pressure presented a satisfactory air content. These conclusions indicate that it is not necessary to worry excessively about the potentially adverse effect of atmospheric pressure on the frost resistance of concrete if a suitable AEA is applied. Additionally, a supplementary mortar study found that the low temperature of raw materials stored at high elevation would significantly weaken the air entrainment, reminding that potential causes in addition to low atmospheric pressure should also be taken seriously. |
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| institution | Directory Open Access Journal |
| issn | 1996-1944 |
| language | English |
| last_indexed | 2024-03-10T16:29:24Z |
| publishDate | 2020-09-01 |
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| spelling | doaj.art-2b5750603ef440f6a0c74899efd3d1832023-11-20T12:57:37ZengMDPI AGMaterials1996-19442020-09-011318397510.3390/ma13183975Effect of Low Atmospheric Pressure on Air Entrainment in Cement-Based Materials: An On-Site Experimental Study at Different ElevationsXin Chen0Xu Liu1Bo Tian2Yong Ge3Lihui Li4School of Transportation Science and Engineering, Harbin Institute of Technology, Harbin 150090, ChinaSchool of Transportation Science and Engineering, Harbin Institute of Technology, Harbin 150090, ChinaResearch Institute of Highway, Ministry of Transport, Beijing 100088, ChinaSchool of Transportation Science and Engineering, Harbin Institute of Technology, Harbin 150090, ChinaResearch Institute of Highway, Ministry of Transport, Beijing 100088, ChinaThe efficiency and stability of air entrainment in concrete are sometimes found to be weaker at higher elevation. This phenomenon was attributed to the low atmospheric pressure by many researchers, however, the level of influence of atmospheric pressure on concrete air content dramatically varied among different studies. In order to clarify the effect of low atmospheric pressure on air entrainment in cement-based materials, an on-site experimental study was conducted with a rigorous control of irrelevant variables. The study focused on the air-entraining efficiency in cement paste, mortar, and concrete prepared in both low and standard atmospheric pressures. The air bubble stability in fresh mortar and air void characteristics of hardened mortar in different atmospheric pressures were also included. In the study, little effect of low atmospheric pressure on the air-entraining efficiency and air bubble stability in mortar with studied air-entraining agents (AEAs) was found. The air void characteristics were found to be similar between mortar with SJ-2 or 303R type AEAs prepared in different atmospheric pressures. Concrete with either SJ-2 or 303R type AEA prepared in low atmospheric pressure presented a satisfactory air content. These conclusions indicate that it is not necessary to worry excessively about the potentially adverse effect of atmospheric pressure on the frost resistance of concrete if a suitable AEA is applied. Additionally, a supplementary mortar study found that the low temperature of raw materials stored at high elevation would significantly weaken the air entrainment, reminding that potential causes in addition to low atmospheric pressure should also be taken seriously.https://www.mdpi.com/1996-1944/13/18/3975concretemortarcement pasteair contentair-entraining agentlow atmospheric pressure |
| spellingShingle | Xin Chen Xu Liu Bo Tian Yong Ge Lihui Li Effect of Low Atmospheric Pressure on Air Entrainment in Cement-Based Materials: An On-Site Experimental Study at Different Elevations Materials concrete mortar cement paste air content air-entraining agent low atmospheric pressure |
| title | Effect of Low Atmospheric Pressure on Air Entrainment in Cement-Based Materials: An On-Site Experimental Study at Different Elevations |
| title_full | Effect of Low Atmospheric Pressure on Air Entrainment in Cement-Based Materials: An On-Site Experimental Study at Different Elevations |
| title_fullStr | Effect of Low Atmospheric Pressure on Air Entrainment in Cement-Based Materials: An On-Site Experimental Study at Different Elevations |
| title_full_unstemmed | Effect of Low Atmospheric Pressure on Air Entrainment in Cement-Based Materials: An On-Site Experimental Study at Different Elevations |
| title_short | Effect of Low Atmospheric Pressure on Air Entrainment in Cement-Based Materials: An On-Site Experimental Study at Different Elevations |
| title_sort | effect of low atmospheric pressure on air entrainment in cement based materials an on site experimental study at different elevations |
| topic | concrete mortar cement paste air content air-entraining agent low atmospheric pressure |
| url | https://www.mdpi.com/1996-1944/13/18/3975 |
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