Effects of Anionic Emulsifiers and Emulsified Asphalt on Hydration and Microstructure of Cement
Cement-emulsified asphalt (CEA) has been widely used in slab ballastless track and asphalt pavement cold recycling projects because of its high stiffness and toughness. In CEA material, emulsifiers and asphalt affect the cement’s hydration process and microstructure. Thus, to further investigate the...
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| Format: | Article |
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MDPI AG
2023-12-01
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| Series: | Materials |
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| Online Access: | https://www.mdpi.com/1996-1944/17/1/36 |
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| author | Panpan Zhang Yitong Hou Kaimin Niu Bo Tian Hao Wang |
| author_facet | Panpan Zhang Yitong Hou Kaimin Niu Bo Tian Hao Wang |
| author_sort | Panpan Zhang |
| collection | DOAJ |
| description | Cement-emulsified asphalt (CEA) has been widely used in slab ballastless track and asphalt pavement cold recycling projects because of its high stiffness and toughness. In CEA material, emulsifiers and asphalt affect the cement’s hydration process and microstructure. Thus, to further investigate the effects of anionic emulsifiers (AEs) and anionic emulsified asphalt (AEA) with different demulsification rates on the hydration process and microstructure of cement, two types of AE (rapid-setting and slow-setting) and their corresponding AEA were used to prepare modified cement pastes. First, it was confirmed that the AEs and AEA delayed cement hydration by measuring the setting time, X-ray diffraction (XRD) patterns, and electrical resistivity of the cement paste. Then, the microstructure of the cement paste was determined with mercury intrusion porosimetry (MIP) and a scanning electron microscope (SEM), and it was found that AEs and AEA have varying degrees of inhibitory effects on the formation of the cement paste microstructure. Finally, based on the energy dispersive spectrometer (EDS) element content of the cement paste and Fourier transform infrared spectroscopy (FTIR) on the two AEs, the inhibition mechanism of AE and AEA with different demulsifier rates on the cement hydration process was analyzed. The experimental results showed that both AEs and AEA delayed the hydration process of cement to varying degrees and altered the microstructure of cement, and slow setting anionic emulsified asphalt (SAEA) had the greatest impact on the hydration process and microstructure of cement. Compared to pure cement paste, the initial setting time of cement paste mixed with SAEA was delayed by 73.9%, and the final setting time was delayed by 66.7%. After adding SAEA, the most probable aperture of the cement paste increased from 62.50 nm to 71.19 nm after one day of hydration. Due to the fact that there were more carboxyl groups with negative charges, more -COO<sup>−</sup> was adsorbed onto the surface of cement particles in the slow-cracking anionic emulsifier (SAE); compared with the rapid-setting anionic emulsifier (RAE) and the rapid-setting anionic emulsified asphalt (RAEA), the SAE and the SAEA had a stronger delaying effect on the hydration reaction of cement. |
| first_indexed | 2024-03-08T15:03:48Z |
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| id | doaj.art-e03001bac13f42c9a1aec9a751a5a9ff |
| institution | Directory Open Access Journal |
| issn | 1996-1944 |
| language | English |
| last_indexed | 2024-03-08T15:03:48Z |
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| spelling | doaj.art-e03001bac13f42c9a1aec9a751a5a9ff2024-01-10T15:02:15ZengMDPI AGMaterials1996-19442023-12-011713610.3390/ma17010036Effects of Anionic Emulsifiers and Emulsified Asphalt on Hydration and Microstructure of CementPanpan Zhang0Yitong Hou1Kaimin Niu2Bo Tian3Hao Wang4Research Institute of Highway, Ministry of Transport, 8 Xitucheng Road, Haidian District, Beijing 100088, ChinaSchool of Civil Engineering, Chongqing Jiaotong University, Chongqing 400074, ChinaResearch Institute of Highway, Ministry of Transport, 8 Xitucheng Road, Haidian District, Beijing 100088, ChinaResearch Institute of Highway, Ministry of Transport, 8 Xitucheng Road, Haidian District, Beijing 100088, ChinaSchool of Civil Engineering, Chongqing Jiaotong University, Chongqing 400074, ChinaCement-emulsified asphalt (CEA) has been widely used in slab ballastless track and asphalt pavement cold recycling projects because of its high stiffness and toughness. In CEA material, emulsifiers and asphalt affect the cement’s hydration process and microstructure. Thus, to further investigate the effects of anionic emulsifiers (AEs) and anionic emulsified asphalt (AEA) with different demulsification rates on the hydration process and microstructure of cement, two types of AE (rapid-setting and slow-setting) and their corresponding AEA were used to prepare modified cement pastes. First, it was confirmed that the AEs and AEA delayed cement hydration by measuring the setting time, X-ray diffraction (XRD) patterns, and electrical resistivity of the cement paste. Then, the microstructure of the cement paste was determined with mercury intrusion porosimetry (MIP) and a scanning electron microscope (SEM), and it was found that AEs and AEA have varying degrees of inhibitory effects on the formation of the cement paste microstructure. Finally, based on the energy dispersive spectrometer (EDS) element content of the cement paste and Fourier transform infrared spectroscopy (FTIR) on the two AEs, the inhibition mechanism of AE and AEA with different demulsifier rates on the cement hydration process was analyzed. The experimental results showed that both AEs and AEA delayed the hydration process of cement to varying degrees and altered the microstructure of cement, and slow setting anionic emulsified asphalt (SAEA) had the greatest impact on the hydration process and microstructure of cement. Compared to pure cement paste, the initial setting time of cement paste mixed with SAEA was delayed by 73.9%, and the final setting time was delayed by 66.7%. After adding SAEA, the most probable aperture of the cement paste increased from 62.50 nm to 71.19 nm after one day of hydration. Due to the fact that there were more carboxyl groups with negative charges, more -COO<sup>−</sup> was adsorbed onto the surface of cement particles in the slow-cracking anionic emulsifier (SAE); compared with the rapid-setting anionic emulsifier (RAE) and the rapid-setting anionic emulsified asphalt (RAEA), the SAE and the SAEA had a stronger delaying effect on the hydration reaction of cement.https://www.mdpi.com/1996-1944/17/1/36anionic emulsifieranionic emulsifier asphalthydration processmicrostructuredelaying effect |
| spellingShingle | Panpan Zhang Yitong Hou Kaimin Niu Bo Tian Hao Wang Effects of Anionic Emulsifiers and Emulsified Asphalt on Hydration and Microstructure of Cement Materials anionic emulsifier anionic emulsifier asphalt hydration process microstructure delaying effect |
| title | Effects of Anionic Emulsifiers and Emulsified Asphalt on Hydration and Microstructure of Cement |
| title_full | Effects of Anionic Emulsifiers and Emulsified Asphalt on Hydration and Microstructure of Cement |
| title_fullStr | Effects of Anionic Emulsifiers and Emulsified Asphalt on Hydration and Microstructure of Cement |
| title_full_unstemmed | Effects of Anionic Emulsifiers and Emulsified Asphalt on Hydration and Microstructure of Cement |
| title_short | Effects of Anionic Emulsifiers and Emulsified Asphalt on Hydration and Microstructure of Cement |
| title_sort | effects of anionic emulsifiers and emulsified asphalt on hydration and microstructure of cement |
| topic | anionic emulsifier anionic emulsifier asphalt hydration process microstructure delaying effect |
| url | https://www.mdpi.com/1996-1944/17/1/36 |
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