POSSIBLE USES OF BAGASSE ASH AS AN ALTERNATIVE CEMENT

POSSIBLE USES OF BAGASSE ASH AS AN ALTERNATIVE CEMENT

Abstract:

This study is an i n v e s t i g a t i o n i n t o the p o s s i b l e use of bagasse ash, SCBA, as an a l t e r n a t i v e cementing m a t e r i a l . The SCBA was used in c o n j u n c t i o n with lime ( i . e . as a pozzolana) to produce lime-pozzolana cement, and with o r d i n a r y p o r t l a nd cement, OPC (as a p a r t i a l replacement) to produce blended p o z z o l a n i c cement. Bagasse is the fibrous r e s i d u e of sugar cane a f t er c r u s h i n g and e x t r a c t i o n of j u i c e . SCBA is the r e s u l t i n g waste product o b t a i n e d from the combustion of b a g a s s e . The SCBA was o b t a i n e d by burning bagasse in a furnace at a temperature of 400°c. p r e l i m i n a r y i n v e s t i g a t i o n was i n i t i a t e d to a s c e r t a i n the composition and p r o p e r t i e s of the SCBA. A desk, top chemical i n v e s t i g a t i o n c a r r i e d out on the SCBA, revealed the presence of s i l i c a (SiO2 ) in a l a r g e amount (about 58.65%). The combined r a t i o of s i l i c a , alumina and f e r r o u s oxide was determined as 70.86%, i n d i c a t i v e of a good pozzolana. The r e a c t i v i t y of the SCBA was measured through i t s pozzolanic a c t i v i t y index (PAI). The PAI with cement and with lime were found to be 91% and 4.88Mpa r e s p e c t i v e l y , and these t o g e t h e r suggest a r e a c t i ve pozzolana. T r i a l compressive s t r e n g t h t e s t s were c a r r i e d out on v a r i o us mixes of the 5CBA with lime and OPC to produce masonry u n i ts of c o n s t a n t cement – sand r a t i o of 113. The r e s u l t s of the i n i t i a l t e s t s , revealed the b e s t performances of lime – SCBA as 25 175, and OPC-SCBA as 75:25 m i x t u r e s . These r e s u l t s were f u r t h e r s u b s t a n t i a t e d with compressive s t r e n g t h t e s t s c a r r i ed vi out on a population of 86 test specimens. The lime – SCBA (25:75) mixture was found to have a strength property of 6.27MPa and 7.48MPa at ages of 7 and 28 days respectively. These values clearly meets the requirements of ASTM for non-load bearing masonry u n i t s . For the OPC-SCBA mixes, an optimum evaluation of strength v i s – a – v i s replacement of OPC made, showed that a maximum of 25% replacement can be made without adverse loss in compressive strength value. The compressive strength value was measured as 20.3MPa at 28 days which is 85.98% of result obtained with control test specimens. Generally, increases in the substitution of OPC with SCBA gave progressively lower compressive strength values, in all a t o t a l of 171 test specimens were prepared and tested. A cost evaluation of the prepared units revealed that pozzolanic cements are cheaper than pure OPC. A savings of 13.25% and 15.74% were recorded for the 75:25 (OPC + SCBA) and 25:75 (LIME + SCBA) cement mixtures respectively.

POSSIBLE USES OF BAGASSE ASH AS AN ALTERNATIVE CEMENT

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