CO_(2)养护压力对植生混凝土碱度及力学性能的影响  

Effect of CO_(2) Curing Pressure on Alkalinity and Mechanical Properties of Vegetated Concrete

作　　者：张瑞 杨大伟 吴科 王跃锋 陈晓强[1] 刘来宝[3] 张礼华[3] 刘川北[3] 辜涛 ZHANG Rui;YANG Dawei;WU Ke;WANG Yuefeng;CHEN Xiaoqiang;LIU Laibao;ZHANG Lihua;LIU Chuanbei;GU Tao(School of Civil Engineering and Architecture,Southwest University of Science and Technology,Mianyang 621010,China;China Railway Ninth Bureau Group Fifth Engineering Co.,Ltd.,Chengdu 611730,China;School of Materials and Chemistry,Southwest University of Science and Technology,Mianyang 621010,China;State Key Laboratory of Green Building Materials,Beijing 100024,China)

机构地区：[1]西南科技大学土木工程与建筑学院,绵阳621010 [2]中铁九局集团第五工程有限公司,成都611730 [3]西南科技大学材料与化学学院,绵阳621010 [4]绿色建筑材料国家重点实验室,北京100024

出　　处：《硅酸盐通报》2023年第10期3499-3507,共9页Bulletin of the Chinese Ceramic Society

基　　金：绿色建筑材料国家重点实验室开放基金课题(2022GBM08);国家自然科学基金(52178254);四川省自然科学基金青年基金(2023NSFSC0931);四川省重点研发项目(2023YFS0360);中铁九局集团第二工程有限公司科研项目(2022年宜威第2号);西南科技大学博士基金(22zx7131)。

摘　　要：本文研究了植生混凝土的碱度及力学性能随CO_(2)养护压力的变化规律,并结合X射线衍射定量相分析(XRD-QPA)、热重分析(TGA)及扫描电子显微镜(SEM)等方法,探讨了CO_(2)养护压力对反应速率及产物生成的影响。结果表明:增大CO_(2)养护压力可提高硅酸三钙(C3S)、硅酸二钙(C_(2)S)及氢氧化钙(CH)的碳化速率,同时可快速生成碳化致密层,有利于延缓CH的生成与溶出;碳化反应生成的碳酸钙(CaCO_(3))及水化硅酸钙(C-S-H)凝胶增大了水泥石密实度,可有效提升植生混凝土的抗压强度。与常压CO_(2)养护相比,在CO_(2)养护压力为0.3 MPa的条件下养护1 h,植生混凝土3 d抗压强度提高了72.8%,28 d抗压强度提高了4.8%,28 d的pH值由11.4降低至8.2。适度提高CO_(2)养护压力对植生混凝土降碱和增强效果良好。In this paper,the variation laws of alkalinity and mechanical properties of vegetated concrete with CO_(2) curing pressure were investigated,and the effect of CO_(2) curing pressure on the reaction rate and product generation was discussed by combining X-ray diffraction quantitative phase analysis(XRD-QPA),thermogravimetric analysis(TGA)and scanning electron microscopy(SEM).The results show that increasing the CO_(2) curing pressure can improve the carbonation rate of tricalcium silicate(C3S),dicalcium silicate(C_(2)S)and calcium hydroxide(CH).At the same time,the carbonized dense layer can be generated rapidly,which is conducive to delaying the generation and leaching of CH.The calcium carbonate(CaCO_(3))and hydrated calcium silicate(C-S-H)gel generated by the carbonation reaction increase the cement stone compactness and effectively improve the compressive strength of vegetated concrete.Compared with normal pressure CO_(2) curing,the 3 d compressive strength of vegetated concrete cured under CO_(2) curing pressure of 0.3 MPa for 1 h increases by 72.8%,the 28 d compressive strength increases by 4.8%,and the 28 d pH value decreases from 11.4 to 8.2.Moderately increasing the CO_(2) curing pressure is effective in reducing the alkalinity and increasing the strength of vegetated concrete.

关 键 词：植生混凝土 降碱 CO_(2)养护压力 碳化致密层 抗压强度 

分 类 号：TU528[建筑科学—建筑技术科学]