掺矿物掺合料盾构管片混凝土的高温性能研究

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发布时间：2021-09-07

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掺矿物掺合料盾构管片混凝土的同目．一
马保国，穆松，高英力，王耀城
日
皿性能研究
(武汉理工大学，硅酸盐材料工程教育部重点实验室，湖北武汉430070)
摘要：混凝土作为盾构隧道中钢筋混凝土管片结构的关键组成部分，与钢筋混凝土结构的稳定性与耐久
性密切相关，而不同矿物掺合料制备的混凝土性能存在差异。在800 ℃ 条件下，以所设计的混凝土钢筋
保护层厚度处(50 mm)温度达到250℃ 的时间确定为耐火极限，研究了不同矿物掺合料制备的盾构管
片混凝土在高温作用下的性能。结果表明：混凝土试件在经历高温作用时，其中心处的温度变化速率包
括成峰，波动和平稳三个阶段。掺加25 矿粉试件(J2)的耐火极限为19 min，爆裂面积为7．06 cm ，测
试结果优于纯水泥体系试件(JO)和掺加20 粉煤灰试件(J3)。JO，J2和J3达到耐火极限后冷却36 h
的物理力学性能损失率相近：抗压强度损失率约为50 ，弹性模量损失率约为40 。此外，J0，J2和J3
的超声波声速值约为2．5 km／S。
关键词：混凝土；高温；耐火极限；物理力学性能；爆裂程度；超声波
中图分类号：TQ172 文献标志码：A 文章编号：1006—7329(2008)01—0125—04
Study on High Temperature Performance of
Shield Tunnel Segment Concrete Containing M ineral Additive
M A Bao—guo，M U Song，GAO Ying—li，W ANG Yao—cheng
(Key laboratory for Silicate Materials Science and Engineering of M inistry of Education，W uhan University of Technology，W uhan
430070。China)
Abstract：Concrete is a key part of the reinforced concrete structure for shield tunnel segments，and is closely
related tO the stability and durability of the structure．There iS a difference between concrete performances
prepared with different mineral additives．The limit of fire resistance(as defined by this paper)is the time when
the temperature at the surface of rebar has reached 250 ℃ in a oven temperature of 800 ℃ for the RC with a
cover of 25mm．The high— temperature performance of concretes prepared with different mineral additives is
studied．The results show that the temperature variation rate of concrete specimens experience three stages：
peak，fluctuation and a smooth one．In addition．the sample with 25 ground granulated slag (J2)has better
performance than the pure cement sample (J0) and the sample with 20 fly ash (J3)． As far as J2 is
concerned，the 1imit of fire resistance is 1 9 min with a spalling area of 7．06 cm ．After cooling for 36 hours after
the concrete arrives at limit of fire resistance，J0，J2 and J3 are similar in physical and mechanical properties：
lOSS of compressive strength iS about 50 ，lOSS of elastic modulus is about 40 V0，and the ultrasonic velocity iS
about 2．5 km／s．
’
Keywords：concrete；high temperature；limit of fire resistance； physical and mechanical properties；spalling
degree；ultrasonic
在盾构隧道中，管片是隧道结构骨架和防水主体，
也是最重要和最关键的衬砌结构构件，而目前在盾构
隧道衬砌结构中应用最广泛的是钢筋混凝土管片。混
凝土作为钢筋混凝土管片结构的关键组成部分，其性
能直接与管片的使用性能和寿命相关。当高温作用
时，混7凝土中水泥石脱水、集料晶型转化、分解高蒸
汽压等物理化学性质的变化所产生的应力应变作用
下，导致了性能的劣化，并最终造成了钢筋}昆凝土结构