掺脱硝粉煤灰混凝土的氨气释放连续检测装置与方法  

Continuous detecting device and method for ammonia release of concrete mixed with denitrified fly ash

作　　者：张思佳[1] 孔祥芝[1] 吴葵 纪国晋[1] 刘艳霞[1] ZHANG Sijia;KONG Xiangzhi;WU Kui;JI Guojin;LIU Yanxia(Beijing IWHR-KHL Co.,Ltd.,China Institute of Water Recourses and Hydropower Research,Beijing 100038,China)

机构地区：[1]中国水利水电科学研究院北京中水科海利工程技术有限公司,北京100038

出　　处：《混凝土》2021年第4期116-118,121,共4页Concrete

基　　金：“十三五”国家重点研发计划项目(2017YFC0405004,2016YFB0303601-3);中国水科院基本科研业务费专项(SM0145B632017,SM0145B842017);中国水科院青年科学研究专项(SM0145B262019);中国长江三峡集团公司科研项目(JG/18032B)。

摘　　要：混凝土掺脱硝粉煤灰后存在氨气释放,对混凝土性能产生不利影响,也对水工隧洞和地铁等封闭空间的施工人员健康存在危害性风险,研究混凝土掺脱硝粉煤灰后的氨气释放规律可为消除这些不利影响提供解决方案,且氨气的释放是一个连续而缓慢的过程,目前缺少有效的检测方法。为解决混凝土掺脱硝粉煤灰后的氨气释放量无法连续吸收和检测难题,本文研发了一种混凝土中氨气释放量连续检测装置,该装置可调控试验箱内温度与风速,以模拟施工环境、振捣和硬化过程,实现混凝土从浇筑到养护过程中氨气释放量的实时检测。采用该装置测试了掺脱硝粉煤混凝土在振捣与硬化过程中的氨气释放规律,结果表明,振捣会加速混凝土中氨气释放,而通气有利于氨气消散,试验箱中氨气浓度随通气时间增加逐渐降低并趋于零;混凝土中氨气释放总量在硬化早期显著增加,随时间增长而逐渐提高最终趋于稳定;混凝土中氨气释放速率符合指数衰减规律。The ammonia released from concrete mixed with denitrified fly ash has a negative impact on the performance of concrete,and is also hazardous to the health of constructors in closed spaces such as hydraulic tunnels and subways.The study of ammonia releasing law of concrete mixed with denitrified fly ash can provide a solution to eliminate these adverse effects.Moreover,ammonia releasing is a continuous and slow process,and there is no effective detection method at present.In order to solve the problem that ammonia release from concrete mixed with denitrified fly ash cannot be absorbed and detected continuously,a continuous testing device for ammonia release from concrete is developed,which can adjust the temperature and wind speed in the test box to simulate the construction environment,vibration and hardening process,and realize the real-time detection of ammonia release from pouring to curing of concrete.The ammonia releasing law of concrete mixed with denitrified fly ash in the process of vibrating and hardening was tested.The results show that vibrating can accelerate ammonia releasing in concrete,and ventilation is beneficial to ammonia dissipation.The ammonia concentration in the test chamber decreases gradually and tends to zero with the increase of ventilation time.The total ammonia release from concrete increases significantly in the early hardening stage and gradually increases with the time,and finally tends to be stable.The release rate of ammonia in concrete accords with the exponential decay law.

关 键 词：脱硝粉煤灰 氨气释放量 装置 方法 释放规律 

分 类 号：TU528.041[建筑科学—建筑技术科学]