Suitability of Gum Arabic as a Plasticizer in Self-Compacting Concrete: Fresh Concrete Properties
1P.W. Zakka, 2P.D Bang, 3H. S. Yohanna, 1O.F. Job and 1 N.A. Anigbogu
1Department of Building, Faculty of Environmental Sciences, University of Jos
2National Film Co-orperation of Nigeria (NFC), Jos
3 Department of Building, Faculty of Environmental Sciences, Bells University Otta
ABSTRACT
In the production of self-compacting concrete, superplaticizers and viscosity modifying agents play an important role in the performance of the concrete. However, these superplarticizer as well as viscosity modifying agents are expensive and their environmental friendliness cannot be guaranteed as most manufactures keep their composition secret. Gum arabic is an abundant and available material found in about 12 states in Nigeria, and is non-reactive or harmful to the environment. The study therefore investigated empirically its suitability as a plasticizer in self-compacting concrete. The research identified the most suitable mix proportion for the self-compacting concrete using gum arabic as a plasticizer. The study made use of a fine/coarse aggregate content of 55:45% content which represents a 1:2 ½: 2 Mix. The water/cement of 0.40 and 0.45 were used as well as a superplasticizer content of 0.9 and 1.5% the weight of cement were used. It was observed that the concrete made with a water cement ratio of 0.45 and a gum arabic content of 0.9% the weight of cement had a slump flow of 560mm, a V-funnel of 9 secs, an L-box value of 0.65 and 0% segregation. The concrete made with a water/cement ratio of 0.40 and a gum Arabic content of 1.5% had a slump flow of 590mm, a V-funnel time of 7 secs, an L-box value of 0.76 and 0% segregation. The concrete made with a water/cement ratio 0.45 and a gum arabic content of 0.9% the weight of cement had a slump flow of 660mm, a V-funnel time of 5.5 secs, L-box value of 0.80 and 0% segregation. The concrete made with a water/cement ratio of 0.45 and a gum arabic content of 1.5% the weight of cement had a slump flour of 680mm, a V-funnel time of 5 sec, L-box value of 0.80 and 0% segregation. The concrete made with 0.45 w/c and a gum arabic content of 1.5% the weight of cement meets all the criteria for self-compacting concrete while the other three mixes met 75% of the requirements. Gum arabic has a low viscosity and thus alters the viscosity of water and improves the workability and flow of self-compacting concrete. The samples of the fresh self-compacting concrete belong to the slump flow class SF1 with a slump flow range of 520-700mm. The viscosity test showed that the concrete belongs to the VF1 class, since their time of flow through the V-funnel was less than 10s. The concrete made with a water cement ratio of 0.45 had more passing ability than the one made with a water/cement ratio of 0.40. There was no form of segregation observed in any of the concrete mixes. The concrete made with a water/cement ratio of 0.40 had a lower slump flow and flowability than the one made with a water/cement ratio of 0.45. The SCC made with Gum Arabic as a plasticizer meets the minimum standard required for SCC after its properties were evaluated.
Keywords: Suitability, Gum Arabic, Plasticizer, Self-Compacting Concrete, Fresh, Properties.
