The particle morphologies of bagasse ash are shown in Fig. 2. The bagasse ash particles have irregular shape, large size, rough surface, and have high porosity. The original bagasse ash (see Tables 1 and 2) has particles retaining on a 45-lm sieve of 66.85% by weight and has strength activity indices at 7 and 28 days of 62% and 74%, respectively. These results suggested that the original bagasse ash is not qualified to be used as a pozzolanic material in concrete because
the physical requirements of ASTM C 618 [15] limit the pozzolan particles retained on a 45-lm sieve to not exceed 34% and should have strength activity index at least 75% at 7 or 28 days. Therefore, the original bagasse ash was ground to improve its reactivity because pozzolanic materials with high fineness exhibit high pozzolanic activity [16]. After grinding, the ground bagasse ash (GBA) had higher fineness and lower porosity than the original bagasse ash. The amount of retained particles of GBA on a 45-lm sieve was reduced to 0.42% by weight and the strength activity indices at 7 and 28 days were 87.4% and 112.7%, respectively. Physical properties, strength activity index, and chemical composition
of the materials are reported in Tables 1–3, respectively. It is noted that GBA had loss on ignition (LOI) of 19.6% which was higher than the limitation of natural pozzolan, which was 10% by weight as specified by ASTM C618-00 [15]. However, Chusilp et al. [17] reported that the high LOI content in bagasse ash which was up to 20% by weight slightly affected the compressive strength of mortar when the age of mortar was more than 28 days.
The particle morphologies of bagasse ash are shown in Fig. 2. The bagasse ash particles have irregular shape, large size, rough surface, and have high porosity. The original bagasse ash (see Tables 1 and 2) has particles retaining on a 45-lm sieve of 66.85% by weight and has strength activity indices at 7 and 28 days of 62% and 74%, respectively. These results suggested that the original bagasse ash is not qualified to be used as a pozzolanic material in concrete becausethe physical requirements of ASTM C 618 [15] limit the pozzolan particles retained on a 45-lm sieve to not exceed 34% and should have strength activity index at least 75% at 7 or 28 days. Therefore, the original bagasse ash was ground to improve its reactivity because pozzolanic materials with high fineness exhibit high pozzolanic activity [16]. After grinding, the ground bagasse ash (GBA) had higher fineness and lower porosity than the original bagasse ash. The amount of retained particles of GBA on a 45-lm sieve was reduced to 0.42% by weight and the strength activity indices at 7 and 28 days were 87.4% and 112.7%, respectively. Physical properties, strength activity index, and chemical compositionof the materials are reported in Tables 1–3, respectively. It is noted that GBA had loss on ignition (LOI) of 19.6% which was higher than the limitation of natural pozzolan, which was 10% by weight as specified by ASTM C618-00 [15]. However, Chusilp et al. [17] reported that the high LOI content in bagasse ash which was up to 20% by weight slightly affected the compressive strength of mortar when the age of mortar was more than 28 days.
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