Feasibility of Using Sawdust Ash of Gmelina Arborea Roxb. Tree in Abia State of Nigeria as Admixture in Production of Concrete

Abstract

Gmelina arborea Roxb.,is a rainforest tree that is found in tropical region. The study investigates the feasibility and effect on the properties of concrete by using sawdust ash as pozzolan produced from Gmelina arborea Roxb.,tree in Abia state. Concrete mix of 1:2:4 by volume batching and constant water to cement ratio of 0.6 were used. The slumps were 60, 70, 89, 60, 55 and 47mm at partial replacement of 0, 5, 10, 15, 20 and 25% respectively. The compressive strength at 28th day of curing for 0, 5, 10, 15, 20 and 25% were 27.67, 27.22, 21.22, 20.00, 18.89 and 18.33 N/mm2 respectively. The research on the slump indicates that all the replacements have good workability to be categorized as true slump, with the 10% partial replacement having the highest workability. In addition, the compressive strengths developed at 28th day showed that the concretes developed good strength, which can increase with further age of curing because pozzolanic concrete develops late better strength and durability than ordinary concrete.

Gmelina arborea Roxb., je stablo kišne prašume koje se nalazi u tropskom regionu Nigerije. Studija istražuje izvodljivost i uticaj na osobine betona korišćenjem pepela od piljevine stabla Gmelina arborea Roxb., u državi Abia, Nigerija. Korišćena je betonska mešavina 1:2:4 zapreminskog odnosa i konstantni odnos vode prema cementu od 0,6. Testovi su od 60, 70, 89, 60, 55 i 47 mm uz delimičnu nadoknadu od 0, 5, 10, 15, 20 i 25% dodatka (sadržaj pepela). Vrednosti uzoraka na pritisak posle 28-og dana od očvršćivanja za dodatke od 0, 5, 10, 15, 20 i 25% bila je 27.67, 27.22, 21.22, 20.00, 18.89 i 18.33 N/mm2 retrospektivno. Istraživanje % zamene (dodatka) pokazuje da sve ispitivane vrednosti zamene imaju dobre osobine i mogu se kategorisati kao dobro poboljšanje mešavine, pri čemu 10% delimična zamena (dodatak pepela) daje najbolje osobine betona. Pored toga, čvrstoća betona na pritisak dobijena posle 28. dana pokazuje da beton razvija dobru čvrstoću, koja se može povećavati u narednim godinama, jer pozolanski beton razvija kasnije bolju pritisnu čvrstoću (tvrdoću) i izdržljivost od običnog (standardni) betona.