Research on micro-mechanism of carbonated reactive MgO-stabilized silt
Cai Guanghua1,2 Liu Songyu1,2 Cao Jingjing1,2
1. Institute of Geotechnical Engineering, Southeast University, Nanjing 210096, China
2. Jiangsu Key Laboratory of Urban Underground Engineering &Environmental Safety, Nanjing 210096, China
Abstract：Based on the reactive MgO-CO2 carbonation method, several tests were conducted on the carbonated reactive MgO-stabilized silts with different reactive MgO content, carbonation time and initial water content. Based on the unconfined compression test, X-ray diffraction (XRD), scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP), the micro-mechanism of carbonated silts were explored by analyzing the unconfined compressive strength, chemical compositions, structural morphology and the microscopic pores. The micro-mechanism model of carbonated MgO-stabilized silt was put forward. The research results indicate that the unconfined compressive strength of the carbonated reactive MgO-stabilized silt increases with the reactive MgO content and carbonation time (within 12 hours) whereas decreases with the initial water content. The water content reduces significantly after carbonation and there exists a very good linear negative correlation relationship between the strength and the water content. There are many hydrated magnesium carbonates in the carbonated silt, including prismatic nesquehonite, flaky dypingite/ hydromagnesite and artinite, whose corresponding XRD peaks increase with the reactive MgO content and carbonation time while they decrease with the initial water content. The optimal conditions of reactive MgO content and initial water content exist, thus the pore volume of carbonated silt can be minimum. The unconfined compressive strength of the carbonated silt is linearly related to the corresponding XRD peaks of nesquehonite crystal. The formation of nesquehonite promotes the growth of strength and reduces the pores together with other carbonation products.
蔡光华 刘松玉 曹菁菁. 活性氧化镁碳化加固粉土微观机理研究[J]. 土木工程学报, 2017, 50(5): 105-113.
Cai Guanghua Liu Songyu Cao Jingjing. Research on micro-mechanism of carbonated reactive MgO-stabilized silt. 土木工程学报, 2017, 50(5): 105-113.
