Архив статей журнала

Strength and thermal conductivity properties of thermowood-cement composition and factors influencing these indicators (2024)
Выпуск: № 7 (131), Том 17 (2024)
Авторы: Chernov Vasilii, Gaisin Ilschat, Maltseva Elena, Nosova Anzelika

The paper studies the ways that technological characteristics of thermal wood concrete (TWC) production have on its strength and thermal conductivity properties. TWC is a new, effective wood-cement composition of authors’ development. To produce it the authors used crushed thermally modified wood (TMW) with a certain shape and size as a filler. The research is rationalized by the fact that currently we are facing a lack of both fundamental and applied experimentally confirmed data on TWC. The paper discusses the studies of the compressive strength and thermal conductivity of four groups of TWC samples that were obtained with three types of filler, differing in size and shape, molding method and strength class of cement-sand mortar. The authors determined general impact patterns of the above-mentioned factors on strength and thermal conductivity properties, as well as specific indicators. Moreover, the paper describes the strength classes and grades of TWC that ranged from B1.5 to B3.5 and from M25 to M50, respectively. Thermal conductivity for standard samples ranged from 0.21 to 0.4 W/(mK). It has been concluded that TWC with a finer TMW filler has the most balanced combination of strength, thermal conductivity and deformation properties. Following the results, the authors proposed practical recommendations for TWC production, and further courses for its improvement and research.

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Ground granulated blast furnace slag and fly ash concrete (2024)
Выпуск: № 7 (131), Том 17 (2024)
Авторы: Hoang Minh Duc, Tran Quoc Toan, Lee Sang Hyun

Utilization of ground granulated blast furnace slag (GGBFS) and fly ash (FA) to resolve the problem of increasing discharged and total accumulated industrial waste has attracted public concern. This article presents the research results on the effect of the replacement of up to 60 wt.% cement with GGBFS and FA, separately and in combination. It shows that mineral admixtures improve the workability of concrete mixture and reduce the required water-reducing admixture to reach a defined slump, prolonging the setting time of fresh concrete. The compressive strength of concrete with GGBFS at an early age decreases while increasing at 60 days and 90 days with the GGBFS content from 20 wt.% to 40 wt.%. The compressive strength of concrete with FA well develops at a later age, but it decreases at all ages as the FA replacement ratio increases. Cement replacement with a combined mineral admixture of 20 wt.% GGBFS and 20 wt.% FA does not significantly change the compressive strength at 28 days and later. Based on test result

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