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Effects of silica fume fineness on mechanical properties of steel fiber reinforced lightweight concretes subjected to ambient and elevated temperatures exposure
Author(s) -
Arel Hasan Şahan,
Shaikh Faiz Uddin Ahmed
Publication year - 2018
Publication title -
structural concrete
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.912
H-Index - 34
eISSN - 1751-7648
pISSN - 1464-4177
DOI - 10.1002/suco.201700281
Subject(s) - fineness , materials science , compressive strength , fiber , composite material , silica fume
This paper presents the effects of silica fume (SF) fineness and fiber aspect ratios of steel fiber on fresh and harden characteristics of high‐strength lightweight concrete containing oil palm shell as coarse aggregates. The effect of elevated temperatures on the residual compressive strength of above concretes is also evaluated in this study. Three different SF fineness of 18 400, 21 000, and 28 000 m 2 /kg and 2 different aspect ratios of steel fiber of 40 and 80 are considered. Results show that the increase in SF fineness and steel fiber aspect ratio marginally affect the air‐dry density of steel fiber reinforced lightweight high‐strength concretes, however, the workability is reduced by about 9% to 14% due to increase in SF fineness. The compressive strength of steel fiber reinforced lightweight concretes at all age increases with increase in SF fineness and an improvement of about 37% is observed at 56 days by increasing the SF fineness from 18 400 to 28 000 m 2 /kg. Strong correlations are also observed between the strength improvement factor and the SF fineness. Water absorption of above concretes is also reduced by 3% to 14% due to increase of SF fineness from 18 400 to 21 000 and 28 000 m 2 /kg. The increase of SF fineness also significantly reduces the residual compressive strength loss at 300°C and 450°C. This loss of residual compressive strength is lower in lightweight concretes containing 16 mm long steel fiber than 8 mm long steel fiber. The existing Eurocode model overestimates the residual compressive strength of steel fiber reinforced lightweight concretes containing no SF, however, this discrepancy is significantly reduced with increase in SF fineness.