An investigation on thermal conductivity of fly ash concrete after elevated temperature exposure

Abstract The influence of high temperature on concrete is closely related to the thermal conductivity of concrete. In this paper, the influence of high temperature and micro-environment relative humidity on the thermal conductivity of fly ash concrete were investigated. A high-temperature energy-saving electric resistance furnace and an artificial climate chamber were used to achieve different high temperature and micro-environment relative humidity in specimens, respectively, and the thermal conductivity of specimens were test by thermophysical properties analyzer. The results showed that after exposed to high temperature, the compressive strength and thermal conductivity of both ordinary concrete and fly ash concrete were markedly reduced, and when the specimens were subjected to 550 °C, the compressive strength reduced about 26%. With an increase in micro-environment relative humidity, the thermal conductivity of both ordinary concrete and fly ash concrete were increased and when the relative humidity reached 100%, the thermal conductivity increased about 22%. Under same conditions, the thermal conductivity of fly ash concrete with 30% fly ash replacement was lower than that of ordinary concrete.

[1]  Xiao Jianzhuang,et al.  An Experimental Study on Thermal Conductivity of Concrete , 2010 .

[2]  I. Hager,et al.  The influence of aggregate type on the physical and mechanical properties of high‐performance concrete subjected to high temperature , 2016 .

[3]  Yunping Xi,et al.  Mesoscale model for thermal conductivity of concrete , 2015 .

[4]  Guanglin Yuan,et al.  Effects of stress and high temperature on the carbonation resistance of fly ash concrete , 2017 .

[5]  Gyeongcheol Choe,et al.  Mechanical Properties of Concrete depending on Cooling Conditions After High Temperature Heating , 2014 .

[6]  Ma Qianmin,et al.  Mechanical properties of concrete at high temperature—A review , 2015 .

[7]  Ahmet B. Kizilkanat,et al.  Thermo-physical properties of concrete exposed to high temperature , 2013 .

[8]  Jin-keun Kim,et al.  An experimental study on thermal conductivity of concrete , 2003 .

[9]  Jay G. Sanjayan,et al.  Thermal and mechanical properties of sustainable lightweight strain hardening geopolymer composites , 2017 .

[10]  A. Beaucour,et al.  Aggregate’s influence on thermophysical concrete properties at elevated temperature , 2015 .

[11]  Jianzhuang Xiao,et al.  Review of Research on the High Temperature Resistance of Concrete Structures in Chinese NPP , 2016 .

[12]  Venkatesh Kodur,et al.  Thermal and mechanical properties of fiber reinforced high performance self-consolidating concrete at elevated temperatures , 2011 .

[13]  Shuangxin Li,et al.  An investigation into the thermal conductivity of hydrating sprayed concrete , 2016 .

[14]  Manu Santhanam,et al.  Durability properties of high volume fly ash self compacting concretes , 2008 .

[15]  M. Peltz,et al.  Thermal properties of high-volume fly ash mortars and concretes , 2011 .

[16]  P. Ranjith,et al.  The use of coal combustion fly ash as a soil amendment in agricultural lands (with comments on its potential to improve food security and sequester carbon) , 2013 .