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

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

doi:10.3390/ma15031240

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).

Highlights

The results show that carbonation reduces the strength of ordinary Portland cement-reinforced soil
The results showed that the chemical activity was significantly improved by adding slag to cement
The kaolin was produced by Shanghai Jiujie Industrial Co., Ltd (Shanghai, China).; the P.O 42.5 ordinary Portland cement was produced by Shandong Weizhou Cement Technology Co., Ltd. (Weifang, China); and the P.S.A 42.5 slag Portland cement was produced by Sinoma

Summary

Introduction

Coastal beach and soft foundation reinforcement is a common engineering problem. Cement soil reinforcement is one of the most commonly used, convenient, and economical methods. The manufacture of traditional cement consumes large amounts of energy. With the global promotion of green, carbon neutral development, new requirements are being adopted to reduce cement energy consumption [1]. Slag Portland cement has a beneficial environmental effect because its raw material is an industrial by-product (blast furnace slag). The research on ordinary Portland cement-reinforced soil has progressed significantly, and ordinary Portland cement is widely used as a soil-reinforcement agent

Methods

Results

Discussion

Conclusion