现代大体积混凝土施工新技术研究 (2)

摘要

工程结构中的大体积混凝土如箱形基础，施工期间混凝土水化热引起的温度作用和自身收缩等变形将产生较大的温度应力，若设计和施工不当就会产生危害性裂缝。过去，我国大都采用设置伸缩缝或后浇带的方法来解决这种问题，但由于结构的整体性、使用功能和建设工期等方面的原因，现对这类结构均提出了无缝施工的要求，即在施工中不设伸缩缝或后浇带，同样能够满足设计和施工质量的要求。文章即提出了对这种无缝施工工艺的一些探讨，以期能得到对温度控制措施的一个全面的了解用以指导我们的现场施工。

关键词：大体积混凝土，温度裂缝，控制

                                                目录

摘要······························································Ⅰ

目录······························································Ⅱ

第一章  引言·······················································1

1.1  概述··························································1

1.2  大体积混凝土的特点 ···········································2

第二章  大体积混凝土结构裂缝产生的机理·····························3

2.1  裂缝种类及成因················································3

2.2  大体积混凝土温度裂缝的产生原理 ·····························4

2.2.l  水泥水化热 ··················································5

2.2.2  外界气温变化················································5

2.2.3  约束条件····················································6

2.2.4  混凝土的收缩变形············································6

第三章  大体积混凝土温度裂缝控制···································8

3.1控制混凝土温升··················································8

3.1.1 选用中低热的水泥品种·········································8

3.1.2 掺加外加剂···················································8

3.1.3 粗细骨料选择················································11

3.1.4控制温度应力·················································12

3.1.5 控制混凝土的出机温度和浇筑温度······························15

3.2加强混凝土的保温和养护·········································16

3.2.1 大体积混凝土的养护要求······································16

3.2.2大体积混凝土的养护措施·······································17

3.3 加强混凝土的温度监测工作······································17

第四章 结论·······················································19

参考文献··························································20

致谢······························································21