水泥细度对水泥水化及混凝土早期开裂影响.pdf

WWW.XIICTI
第16卷第5期
建筑材料学报
2013年10月
JOURNAL OF BUILDING MATERIALS
Oct.,2013
文章编号:1007-9629(2013)05-0853-05
水泥细度对水泥水化及混凝士早期开裂影响
王冲,张洪波,杨长辉,钱觉时',钟明全2,李豪举1
(1.重庆大学材料科学与工程学院,重庆400045;
2.重庆市交通规划勘察设计研究院,重庆401121)
摘要:利用微量热仪法研究了细度对水泥水化热及水化放热速率的影响规律,利用非接触式激光
位移传感器和集中约束平板法测试了不同细度水泥混凝土的早期收缩变形与开裂.结果显示:随
着细度的增加,水泥水化热与水化放热速率増加,水化放热峰值时间明显提前;水泥比表面积提
高,混凝土早期收缩增大,早期单位裂缝面积增加,但混凝土水分蒸发速率与最大裂缝宽度减小
建议混凝土工程中应限制水泥过细
关键词;水泥细度;水泥水化;早期收缩;早期开裂
中图分类号:TU528.01
文献标志码:A
doi:10.3969/j.issn.1007-9629.2013.05.020
Influence of Cement Fineness on Hydration of Cement and
Early-age Cracking of Concrete
WANG Chong, ZHA NG Fong-bo, YANG Chang hui, QIAN Jue-shi
ZHONG Ming-quan, LI Hao-ju
(1. College of Materials Science and Engineering, Chongqing University, Chongqing 400045, China
2. Chongqing Institute of Communications Planning Surveying and Designing, Chongqing 401121, China)
Abstract Ccment fineness, cement hydration and concrete cracking are closely related. Influence of cement
fineness on hydration heat and hydration rate of cement was investigated using microcalorimetry. Early-age
shrinkage and early-age cracking of concrete prepared with different fineness cement were determined using
non-contact laser displacement sensor and centralized constrained plate method, respectively. The test re-
sults show that with increase of cement fineness, hydration heat and hydration rate are increased, and time
to peak of hydration is reduced. Increasing the specific surface area of cement causes higher shrinkage and
unit crack area at carly age, but reduces rate of water evaporation and maximum crack width of concrete
According to the research results, it is suggested to set an upper limit value of the cement fineness in con
crete engineering.
Key words: cement fineness; hydration of cement; early age shrinkage; early-age cracking
随着水泥工业技术的发展,水泥细度也在不断了提高了对水泥的强度要求.为满足强度等级要求
变化.从1920年到1990年的70a间,美国水泥的比或从经济利益出发,生产厂家普遍提高了水泥的细
表面积从220m2/kg増加到340~600m2/kg,其7d度、在2007年新修订的标准中,对水泥细度已由原
抗压强度几乎增长了2.5倍り.30a来,中国水泥标先的强制性要求改为选择性要求在实际工程中,硅
准分别于1979,1992,1999,2007年进行了4次修酸盐水泥与普通硅酸盐水泥的细度大多超过
订.从这4次修订的标准来看,前3次都在原基础上.350m2/kg,个别甚至超过了400m2/kg.针对这
收稿日期:20120607;修訂日期:2012-09-03
基金项目;西部交通建设科技项目(2009318000033)
第一作者:王神(1972-),男,守夏中宁人,重庆大学副教授,博士.E-mail: chongwang(cqu.edu.cn