Open AccessEffect of high temperatures on the mechanical behaviour of hybrid cement
Author(s) -
Bo Qu,
Ana Fernández Jiménez,
A. Palomo,
A. Martı́n,
J.Y. Pastor
Publication year - 2020
Publication title -
materiales de construcción
Language(s) - English
Resource type - Journals
eISSN - 1988-3226
pISSN - 0465-2746
DOI - 10.3989/mc.2020.13318
Subject(s) - portland cement , materials science , portlandite , composite material , cement , fly ash , toughness , compressive strength , residual strength , flexural strength , clinker (cement) , fracture toughness
The high-temperature mechanical behaviour of a pre-industrial hybrid alkaline cement (HYC) was studied. The HYC in question contained 30 % Portland clinker and 70 % of a blend of slag, fly ash and a solid activator (mix of alkaline salts with a predominance of Na2SO4). The material was tested during exposure to high temperatures to establish its compressive and bending strength and elastic modulus, as well as fracture toughness, analysed using an innovative methodology to notch the hydrated cement paste specimens. Post-thermal treatment tests were also run to assess residual mechanical strength after 2 h of exposure to temperatures ranging from 400 °C to 1000 °C. TG/DTA, MIP and SEM were deployed to ascertain heat-induced physical-chemical changes in the structure. The higher mechanical strength during and after treatment exhibited by the hardened hybrid alkaline cement than the CEM I 42.5R ordinary portland cement (OPC) paste used as a reference was associated with the lower water and portlandite content found in HYC. Pseudo-plastic behaviour was observed at high temperatures in the loaded HYC in the tests conducted during exposure.