摘要
为实现淤泥质钻渣土低碳与多样化利用,自主研制了温湿控碳化反应釜,对淤泥质钻渣土造粒碳化方法及其强度增长机理开展了系统试验研究。首先使用熟石灰对桩基施工产生钻渣进行改性,并制成粒径12 mm的颗粒状坯料;在反应釜中充入CO_(2)气体,在恒温、恒湿(60℃,湿度80%)条件下对坯料碳化养护8 h,实现钻渣土高强度造粒。碳化结束后,对颗粒进行热重分析(TG)、X射线衍射(XRD)、颗粒强度试验,分析了7种不同熟石灰掺量下碳化颗粒强度增长机理。试验表明,碳化颗粒的碳化率能达到80%以上,主要生成物为方解石型碳酸钙晶体,且碳化颗粒强度随熟石灰掺量增加表现为“先缓增-后快增”的两阶段特点;当熟石灰掺量在12%以下时,碳化颗粒强度随熟石灰掺量缓慢增长,当掺量超过12%以后,碳化生成的大量方解石胶黏土颗粒并形成整体骨架,晶粒尺寸也随掺量逐渐减小并膨胀填充孔隙,颗粒强度进入快增阶段;最终颗粒碳化强度可达3.0 MPa以上。此外,水稳定性试验表明,熟石灰掺量达16%以上时,碳化颗粒具备A等水稳定性能。碳排放分析表明本方法制备的碳化颗粒CO_(2)排放相对陶粒减少了42.7%~52.6%,减碳效益显著。本研究为绿色处置钻渣土,实现其在路基层填料、路基台背填料等场景中利用提供了技术方案。
To enhance the low-carbon and diverse utilization of silty drilling residue,this study proposed a self-designed temperature and humidity-controlled carbonation reactor,and presented systematic experimental investigations into the granulation carbonation method for silty drilling residue and its strength growth mechanism.Firstly,the silty drilling residue,from bridge pile foundation construction,were modified with hydrated lime to produce granular billets with a 12 mm diameter.Subsequently,the reactor was filled with CO_(2) and the granular billets were carbonation cured at constant temperature and humidity(60℃,80%humidity)for 8 hours to obtain high-strength pellets from silty drilling residue.After that,thermal gravimetric analysis(TG),X-ray diffraction(XRD),and pellet strength tests were carried out,providing insights into the strength augmentation mechanisms inherent in carbonated pellets with 7 different amounts of hydrated lime.The experimental results demonstrate that this process yields a remarkable carbonation rate exceeding 80%,primarily resulting in the formation of calcium carbonate crystals of the calcite variety.The strength of carbonated pellets exhibits a discernible dependency on the quantity of hydrated lime,showing a two-stage progression.It presents an initial gradual increase followed by a rapid surge.Specifically,with hydrated lime contents below 12%,the strength of carbonated pellets gradually increases.When exceeding this threshold,a substantial quantity of calcite functions as a binding agent,which interlocks soil grains and forms a coherent structural framework.During this process,the crystal particle size of calcite diminishes progressively that expands and fills into pore spaces,and the pellets strength enters an accelerated period,which can surpass 3.0 MPa.Moreover,the water stability assessments reveal that when hydrated lime content exceeds 16%,carbonated pellets display an exceptional A-grade water stability performance.Remarkably,carbon emissions analysis indicates a noteworthy re
作者
曹志刚
申昆鹏
毛天学
肖力
庄峻淇
CAO Zhi-gang;SHEN Kun-peng;MAO Tian-xue;XIAO Li;ZHUANG Jun-qi(Research Center of Coastal and Urban Geotechnical Engineering,Zhejiang University,Hangzhou 310058,Zhejiang,China;Zhejiang Communications Construction Group Co.Ltd.,Hangzhou 310052,Zhejiang,China)
出处
《中国公路学报》
EI
CAS
CSCD
北大核心
2024年第6期217-227,共11页
China Journal of Highway and Transport
基金
国家自然科学基金项目(51978611)
浙江省自然科学基金项目(LR21E080004)。
关键词
路基工程
淤泥质钻渣土
碳化造粒
路基填料
低碳减排
subgrade engineering
silty drilling residue
carbonation granulation
road base fill-ers
carbon emission reduction Received 06 Sept.2023