Experimental Study on Carbonation Durability of Kaolin Strengthened with Slag Portland Cement

Qingbiao Wang; Yiming Ma; Fuqiang Wang; Zhenyue Shi; Hongyue You; Yuanyuan Tian; Yunfei Liu; Zhongjing Hu; Hongxu Song; Dong Wang; Yueqiang Sun; Rongshuai Yang; Haoran Sun

doi:10.3390/ma15031240

Experimental Study on Carbonation Durability of Kaolin Strengthened with Slag Portland Cement

Materials (Basel). 2022 Feb 7;15(3):1240. doi: 10.3390/ma15031240.

Authors

Qingbiao Wang^{1

2

3}, Yiming Ma¹, Fuqiang Wang⁴, Zhenyue Shi⁵, Hongyue You⁴, Yuanyuan Tian⁴, Yunfei Liu¹, Zhongjing Hu⁵, Hongxu Song⁶, Dong Wang⁴, Yueqiang Sun¹, Rongshuai Yang¹, Haoran Sun¹

Affiliations

¹ College of Resources, Shandong University of Science and Technology, Tai'an 271019, China.
² State Key Laboratory of Mining Disaster Prevention and Control Co-Founded by Shandong Province and the Ministry of Science and Technology, Shandong University of Science and Technology, Qingdao 266590, China.
³ National Engineering Laboratory for Coalmine Backfilling Mining, Shandong University of Science and Technology, Tai'an 271019, China.
⁴ College of Civil Engineering and Architecture, Shandong University of Science and Technology, Qingdao 266590, China.
⁵ College of Safety and Environmental Engineering (College of Safety and Emergency Management), Shandong University of Science and Technology, Qingdao 266590, China.
⁶ College of Energy and Mining Engineering, Shandong University of Science and Technology, Qingdao 266590, China.

Abstract

Slag Portland cement is an environmentally friendly and energy-saving product, which is widely used in cement-reinforced soil. This study used slag Portland cement-reinforced soil as the research object and P.O 42.5 + kaolin (POK) as the reference group. The carbonation depth and strength of P.S.A 42.5 + kaolin (PSK) at different curing times were analyzed using carbonation depth, uniaxial ground pressure strength, scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The test results show the following: (1) The active substances in PSK samples can react with calcium hydroxide produced during cement hydration and can reduce the content of OH^-. The PSK samples react with OH^- and CO₂ in the carbonation environment. Both processes considerably reduce the content of OH^-. (2) Due to the decrease in OH^- content, the carbonation durability of slag Portland cement-reinforced soil is significantly less than that of ordinary Portland cement. (3) The carbonation of slag Portland cement-reinforced soil improves its strength. (4) The results of SEM + EDS and XRD confirm the carbonation depth and strength of the POK and PSK samples. The results show that PSK has important applications in subgrade or building grouting materials and in cement-soil mixing piles (walls).

Keywords: carbonation depth; carbonation durability; slag Portland cement; uniaxial compressive strength test (UCST).

Abstract

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