Behaviour and the controlling factor of delayed ettringite formation in shrinkage-compensating massive concrete

2002 ◽  
Vol 54 (5) ◽  
pp. 315-319
Author(s):  
P. Yan ◽  
J. Peng ◽  
X. Qin
Keyword(s):  
Controlling Factor ◽  
Delayed Ettringite Formation ◽  
Massive Concrete ◽  
Ettringite Formation

Study on the Delayed Ettringite Formation in Massive Shrinkage Compensating Concrete with U-Type Expansive Agent

2011 ◽  
Vol 477 ◽  
pp. 340-347
Author(s):  
Qian Wang ◽  
Zheng Yue Ren ◽  
Zhe Zhang
Keyword(s):  
Thermal Stability ◽  
Water Supply ◽  
Ambient Temperature ◽  
Formation Condition ◽  
Test Results ◽  
Delayed Ettringite Formation ◽  
Massive Concrete ◽  
Ettringite Formation ◽  
Simulated Environments ◽  
Expansive Agent

This paper introduces the research results of the thermal stability and the delayed formation of ettringite in China and abroad. Aiming at the debate of the ettringite delayed formation condition of the massive shrinkage compensating concrete in the engineering field, the decomposition and delayed formation of ettringite were studied in simulated environments in massive concrete and other controlled curing environment. As UEA is the most applied expansive agent in domestic, the massive shrinkage compensating concrete mixed with UEA is selected as the research object. The test results show that, AFM appears in the research specimens when the inner temperature reach 80°C and the ettringite can reform under the condition of rich water supply after the concrete cooling to an ambient temperature. By comparing the test results of different curing environment, some points for attention during the construction of the UEA massive shrinkage compensating concrete are proposed.

Heat treatment of fresh concrete by radio waves – Avoiding delayed ettringite formation

2017 ◽  
Vol 143 ◽  
pp. 580-588 ◽  
Author(s):  
Björn Höhlig ◽  
Christof Schröfl ◽  
Simone Hempel ◽  
Ina Noack ◽  
Viktor Mechtcherine ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Fresh Concrete ◽  
Radio Waves ◽  
Delayed Ettringite Formation ◽  
Ettringite Formation

scholarly journals Risk analysis of the delayed ettringite formation in pile caps foundation in the metropolitan region of Recife - PE - Brasil

2016 ◽  
Vol 9 (3) ◽  
pp. 357-394 ◽  
Author(s):  
I. F. Torres ◽  
T. Andrade
Keyword(s):  
Risk Analysis ◽  
Metropolitan Region ◽  
Hardened Concrete ◽  
Chemical Compositions ◽  
Delayed Ettringite Formation ◽  
Ettringite Formation ◽  
Pile Caps ◽  
Foundation Pile ◽  
Physical And Chemical

ABSTRACT Currently, there is an awareness that is critical to assess the durability characteristics of concrete with as much attention as the mechanical properties. The durability of concrete structures can often be affected by chemical attacks, jeopardizing its performance and security. When concrete is subjected to high temperature at early ages, many physical and chemical changes in hardened concrete may occur. It iswidely accepted that concrete subjected to these conditions of temperature and exposed to moisture is prone to cracking due to Delayed Ettringite Formation (DEF). This work aims at providing a DEF risk analysis on foundation pile caps at the Metropolitan Region of Recife - PE. Temperature rise measurement was performed in situ at 5 different caps through datalogger and thermocouples equipments. Furthermore, the Duggan test was performed in order to assess the level of expansion of 3 cements studied: X (CP II E 40), Y (CP II F 32) and Z (CP V ARI RS). Simultaneously, the chemical compositions of these cements and their respective clinkers were quantified by analysis of X-ray fluorescence (XRF). The cement X (CP II E 40) showed the chemical characteristics favoring with more intensity DEF and, as a result, higher level of expansion in the test Duggan. It is noteworthy that incorporation of metakaolin (8% and 16%) and silica fume (5% and 10%) showed mitigating potential of expansions. It is important to point out that all factors related to thermal properties and chemical composition of the concrete used in the region converge to a condition of ideal susceptibility for triggering DEF. Therefore, it is essential at least minimum and basic requirements in the design specification in order to avoid high temperatures in the massive concrete elements, preventing them from delayed ettringite formation.

Sign in / Sign up

Export Citation Format

Share Document