摘要
为了研究浸水、掺加粉煤灰和表面改性3种预处理措施对钢渣膨胀性的抑制机理和抑制效果,采用浸水膨胀率来表征预处理后钢渣的体积变化,通过扫描电子显微镜试验(SEM)研究钢渣预处理后的微观结构变化。结果表明:浸水预处理措施下随着水温的升高,膨胀组分被消解的速率也变快,并在钢渣表面形成水化硅酸钙(C-S-H)保护层。常温下浸水预处理措施消解时间较长,当温度升至60℃时,消解效率能够增长1倍,90℃时消解最快。当在钢渣中逐渐掺入粉煤灰后,其膨胀性逐渐减小,在消解过程中表面也逐渐被火山灰反应的产物包裹,当粉煤灰掺量大于18%时膨胀率降低效果减弱;在水和粉煤灰同时作用的条件下,其膨胀性的抑制效果比单一条件时效果更为优异,掺入12%的粉煤灰,并在60℃条件下浸水15 d,其抑制膨胀性效果最好。表面改性方式处理后的钢渣在表面形成了一层新的界面,增强了钢渣的抗水渗透能力,保证了钢渣的体积安定性,又提高了其力学性能。不同的预处理技术措施对应的处理效果各不相同,但均可以降低钢渣的膨胀性,为钢渣安全应用于道路工程提供技术支持。
In order to investigate the inhibition mechanism and inhibition effect of 3 pretreatment measures(water immersion,fly ash doping and surface modification)on the swelling properties of steel slag,the volume change of steel slag after pretreatment is characterized by water immersion swelling rate,and the microstructural change of steel slag after pretreatment is investigated by scanning electron microscope(SEM)test.The result shows that(1)Under the pretreatment measure of water immersion,the dissolution rate of swelling components becomes faster with the increase of water temperature,and a protective layer of hydrated calcium silicate(C-S-H)is formed on the surface of the steel slag.(2)The dissolution time for the pretreatment measure of water immersion at room temperature is longer.The dissolution efficiency can double when the temperature rises to 60℃,and the dissolution is the fastest at 90℃.(3)After the steel slag is gradually mixed with fly ash,its swelling is gradually weakened,and the surface is gradually wrapped by the products of volcanic ash reaction during the dissolution process.The swelling rate reduction effect is weakened when the doping amount of fly ash is greater than 18%.(4)Under the condition of simultaneous action of water and fly ash,its swelling inhibition effect is more excellent than that under single condition.The best inhibition of swelling is found when 12%fly ash is incorporated and immersed in water at 60℃for 15 days.(5)The steel slag treated by surface modification forms a new interface on the surface,which enhanced the water penetration resistance of the steel slag,ensured the volume stability of the steel slag,and improved its mechanical properties.(6)Different pretreatment technical measures correspond to different treatment effects,but they can all reduce the expansion of steel slag,which can provide technical support for safe application of steel slag in road engineering.
作者
支鹏飞
马红梅
何政文
ZHI Peng-fei;MA Hong-mei;HE Zheng-wen(Gansu Provincial Transportation Research Institute Group Co.,Ltd.,Lanzhou Gansu 730030,China;Gansu Provincial Road Materials Engineering Laboratory,Lanzhou Gansu 730030,China;School of Civil Engineering,Lanzhou Jiaotong University,Lanzhou Gansu 730070,China)
出处
《公路交通科技》
CAS
CSCD
北大核心
2021年第10期30-38,共9页
Journal of Highway and Transportation Research and Development
关键词
道路工程
体积安定性
预处理
钢渣
表面改性
road engineering
volume stability
pretreatment
steel slag
surface modification
