当前位置: X-MOL 学术Cement Concrete Comp. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Strength activity index and bulk resistivity index modifications that differentiate inert and reactive materials
Cement & Concrete Composites ( IF 10.5 ) Pub Date : 2021-08-28 , DOI: 10.1016/j.cemconcomp.2021.104240
Ying Wang 1 , Lisa Burris 2 , Christopher R. Shearer 3 , Douglas Hooton 4 , Prannoy Suraneni 1
Affiliation  

The ASTM C311 strength activity index test is a potentially flawed test because inert materials are known to be able to pass the test. The early age of testing, low fly ash replacement levels, variable water-to-cementitious materials ratio, and low strength limits all contribute to the inability of the test to successfully distinguish inert and reactive materials. Test modifications utilizing higher replacement levels (50% by mass) and higher temperatures (50 °C) are evaluated in this study for three fly ashes and two inert materials. Bulk resistivity is also measured in addition to strength. Using higher replacement levels and higher temperatures provides improved differentiation of inert and reactive materials when using strength, however, the magnitude of differences is somewhat small, when considering variability in strength measurements. On the other hand, higher replacements and especially higher temperatures result in a very substantial increase in bulk resistivity for the fly ashes but not for inert materials. Therefore, a bulk resistivity index test carried out at higher temperatures provides for clear differentiation of inert and reactive materials and should considered for standardization/specification. The calcium hydroxide contents and heat release measured in corresponding cement pastes show that increased temperature enhances fly ash reaction but does not affect inert materials. At higher replacement levels, greater effects of fly ash reaction are manifested, resulting in better differentiation from inert materials than at lower replacement levels.



中文翻译:

区分惰性和反应性材料的强度活性指数和体电阻率指数修改

ASTM C311 强度活性指数测试是一项潜在的有缺陷的测试,因为已知惰性材料能够通过测试。测试时间过早、粉煤灰替代水平低、水与水泥材料的可变比以及低强度限制都导致测试无法成功区分惰性和反应性材料。本研究评估了使用更高替代水平(按质量计 50%)和更高温度 (50 °C) 的测试修改,用于三种粉煤灰和两种惰性材料。除了强度之外,还测量体电阻率。在使用强度时,使用更高的置换水平和更高的温度可以更好地区分惰性和反应性材料,但是,在考虑强度测量的可变性时,差异的幅度有点小。另一方面,更高的置换率,尤其是更高的温度,会导致飞灰的体电阻率显着增加,但惰性材料不会。因此,在较高温度下进行的体电阻率指数测试可以明确区分惰性和反应性材料,并应考虑标准化/规范。在相应的水泥浆中测量的氢氧化钙含量和放热表明升高的温度会增强飞灰反应,但不会影响惰性材料。在较高的替代水平下,飞灰反应的影响更大,导致与较低的替代水平相比,更好地区分惰性材料。更高的置换率,尤其是更高的温度,会导致飞灰的体电阻率显着增加,但惰性材料不会。因此,在较高温度下进行的体电阻率指数测试可以明确区分惰性和反应性材料,并应考虑标准化/规范。在相应的水泥浆中测量的氢氧化钙含量和放热表明升高的温度会增强飞灰反应,但不会影响惰性材料。在较高的替代水平下,飞灰反应的影响更大,导致与较低的替代水平相比,更好地区分惰性材料。更高的置换率,尤其是更高的温度,会导致飞灰的体电阻率显着增加,但惰性材料不会。因此,在较高温度下进行的体电阻率指数测试可以明确区分惰性和反应性材料,并应考虑标准化/规范。在相应的水泥浆中测量的氢氧化钙含量和放热表明升高的温度会增强飞灰反应,但不会影响惰性材料。在较高的替代水平下,飞灰反应的影响更大,导致与较低的替代水平相比,更好地区分惰性材料。在较高温度下进行的体电阻率指数测试可明确区分惰性和反应性材料,应考虑标准化/规范。在相应的水泥浆中测量的氢氧化钙含量和放热表明升高的温度会增强飞灰反应,但不会影响惰性材料。在较高的替代水平下,飞灰反应的影响更大,导致与较低的替代水平相比,更好地区分惰性材料。在较高温度下进行的体电阻率指数测试可明确区分惰性和反应性材料,应考虑标准化/规范。在相应的水泥浆中测量的氢氧化钙含量和放热表明升高的温度会增强飞灰反应,但不会影响惰性材料。在较高的替代水平下,飞灰反应的影响更大,导致与较低的替代水平相比,更好地区分惰性材料。

更新日期:2021-09-02
down
wechat
bug