This paper reports the investigated thermogravimetry analysis, compressive strength and thermal conductivity tests of non-autoclaved aerated Portland cement-fly ash-silica fume concrete. The mixes were cured in water and air for 3, 7 and 28 days. Thermogravimetry results showed that calcium silicate hydrate (C-S-H), ettringite, gehlenite (C 2 ASH 8 ), calcium hydroxide [Ca(OH) 2 ] and calcium carbonate (CaCO 3 ) phases were detected in all mixes. The compressive strength and thermal conductivity of aerated Portland cement-fly ash-silica fume concrete increased when compared with aerated Portland cement-fly ash concrete after 28 days. The compressive strength and thermal conductivity of aerated concrete cured in water had higher values than air-cured specimens. X-ray diffraction and thermogravimetry showed that Ca(OH) 2 decreased with increased silica fume content. This is due to the increased pozzolanic reaction when compared with the Portland cement-fly ash mixes, which corresponds to an increase in compressive strength and thermal conductivity.
This paper investigated the compressive strength and thermal conductivity of water and air cured Portland cement-fly ash-silica fume mortars. The results showed that density, compressive strength and thermal conductivity of blended cement mortars with fly ash were lower than Portland cement control. However, blended cement mortars that contained silica fume as replacement cement both in binary and ternary phase were higher than fly ash mixes and tends to increase with increase silica fume used as cement replacement due to increased C-S-H phase formation from pozzolanic reaction and its filler effect. In ternary phase, compressive strength and thermal conductivity of 10FA5SF and 5FA10SF mixes had values higher than Portland cement control while 20FA10SF mixes had values similar to Portland cement control. The density, compressive strength and thermal conductivity of blended cement mortars those cured in saturated lime water were higher than air cured specimens. Moreover, relationships between compressive strength and thermal conductivity as well as density and thermal conductivity were compared. X-ray diffraction traces show that intensity of C-S-H phase increased while intensity of Ca(OH)2 decreased with increased silica fume content due to the increased pozzolanic reaction when compared to the reference FA mix.
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