钢渣碳化砖的碱激发-碳化协同效应影响因素  

Synergistic Effect of Alkali-activation and Carbonation on Carbonated Steel Slag Bricks

作　　者：叶家元 张文生 史迪 司政凯 陈晓飞 YE Jiayuan;ZHANG Wensheng;SHI Di;SI Zhengkai;CHEN Xiaofei(The State Key Laboratory of Green Building Materials,China Building Materials Academy,Beijing 100024,China;Henan Xingan New Building Materials Co.Ltd.,Zhengzhou 450100,China)

机构地区：[1]中国建筑材料科学研究总院有限公司,绿色建筑材料国家重点实验室,北京100024 [2]河南兴安新型建筑材料有限公司,郑州450100

出　　处：《硅酸盐学报》2019年第11期1582-1592,共11页Journal of The Chinese Ceramic Society

基　　金：国家自然科学基金项目(51572252)资助;国家“863”计划课题(2009AA03Z506)资助

摘　　要：以钢渣为主要原料制备了钢渣碳化砖,分析了其在碱激发条件下的碳化效果影响因素。结果表明,钢渣因含有f-CaO、硅酸二钙等可碳化组分而表现为更高的CO2吸收量,是适宜的原材料。Na2CO3激发能力恰当且可提升碳化效果,是适宜的激发剂。掺用Na2CO3时,碳化强度随钢渣用量增加而增大,但钢渣用量达到1 800 kg/m^3时CO2吸收量显著下降;强度几乎不受钢渣细度影响,CO2吸收量随钢渣细度增加而增加,但细度超过440 m^2/kg时CO2吸收量增加变缓;碳化砖的强度随骨料用量增加而增大,但CO2吸收量变化不明显。占钢渣7%~13%的水用量可使试样具有足够好的碳化效果,但水用量为11%、13%时CO2吸收量下降。7%水用量时钢渣砖碳化后强度增长20.0 MPa以上,在0.75%Na2CO3对钢渣的激发作用并协同碳化作用条件下,可使强度再增长10.0 MPa、CO2吸收量再增加1%以上;然而当Na2CO3用量超过1%,增强作用变弱、CO2吸收量下降。钢渣碳化砖的适宜配比为:钢渣(比表面积440 m^2/kg)1640 kg/m^3,骨料328 kg/m^3 (占钢渣的20%,下同),水115 kg/m^3 (7%),Na2CO3 13.12 kg/m^3 (0.75%)。该配比制备的试样碳化后其抗压强度、CO2吸收量可分别达到39.2 MPa、9.15%。在碳化过程中生成更多且沉积于孔洞的碳酸钙,获得更致密基体,是碱激发协同碳化增强的主要原因。The effect of alkali-activation with carbonation on the properties of carbonated steel slag bricks was investigated. The results show that steel slag is a suitable starting material for carbonated bricks due to its CO2 sequestration. Na2 CO3 as a feasible activator shows a better improvement according to the strength growth and CO2 sequestration. The strength of carbonated bricks containing Na2 CO3 increases with the increase of steel slag volume, but CO2 sequestration gradully decreases due to the more compact matrix in which the steel slag volume is 1 800 kg/m^3. The bricks made of steel slag powder with a greater fineness have a greater CO2 sequestration, but the increment of CO2 sequestration of the bricks made of ultra-fine powder with a fineness of more than 440 m^2/kg becomes weak. A high volume of aggreagte causes a greater sthrength, and the change in CO2 sequestration does not appear. A suitable dosage of water in steel slag(i.e., 7%–13%) can favor carbonating, but the excessive water(i.e. 11%–13%) leads to a decrease of CO2 sequestration. The solely accelerated carbonation leads the strength of bircks with 7% water to increase by more than 20.0 MPa. Furher more, the incorporation of 0.75% Na2 CO3 results in a further strength gain of more than 10.0 MPa due to the synergetic effect of carbonation and alkali-activation. The optimized mixture of bricks consists of 1 640 kg/m^3 of steel slag with a specific surface area of 440 m^2/kg, 328 kg/m^3 of aggreagte(20%, mass ratio of aggregate to steel slag, the same below), 115 kg/m^3 of water(i.e., 7%) and 13.12 kg/m^3 of Na2 CO3(i.e., 0.75%). The strength of optimized carbonated bricks with CO2 sequestration of 9.15% is 39.2 MPa. The more calcite foramtion and its stronger filling effect are the main reason for the strength gain of carbonated bricks activated by Na2 CO3.

关 键 词：钢渣 碱激发 碳化 协同效应 碳化砖 

分 类 号：TU528[建筑科学—建筑技术科学]