The Effect of Gum Arabic on Sisal Fibre-Reinforced Concrete: Alternative Material for Prevention of Balling
Audu Isa Ibrahim Dakas1, Segun Emmanuel Agboju2 and Akolo Peter Enjugu3
1,2,3Department of Building, Faculty of Environmental Sciences
University of Jos, Jos
Email: abdullahidakas@gmail.com
Corresponding Author: Audu Isa Ibrahim Dakas
ABSTRACT
Fibre has been identified and used in construction, especially in buildings. However, balling, a situation where fibre clumps together discourages its use, especially where the volume fraction of the fibre is greater than 1%. Balling reduces workability which consequently creates voids in concrete leading to reduced compressive strength. In this study, balling in sisal fibre-reinforced concrete was evaluated using gum Arabic, known for increasing the workability of plain concrete. The effect of the dispersed fibre by the action of the gum Arabic on both the fresh and hardened properties of concrete was checked. Performance of two categories of 100 mm concrete cube specimens were considered, comprising control mix of 1:2:4 sisal fibre-reinforced concrete with 3% volume fraction (Vf) of the fibre cut into 30 mm length and gum Arabic of 0.2%, 0.4%, 0.6%, and 0.8% the weight of cement. Water/cement ratio was fixed at 0.6. The concrete cube specimens were cured at 7, 14 and 28 days and the results show that the addition of 3% sisal fibre to the concrete mixture affected the properties of the fresh concrete as it was difficult getting a homogenous mix because of the balling of the fibre. However, addition of gum Arabic into the concrete mix gradually reduced the balling and mixing became much easier and more homogenous. Consequently, there was gradual rise in workability due to the addition of gum Arabic from 0.4% to 0.8%, the weight of cement. Also, the compressive strength of the concrete specimens increased when compared to the control mix (0% gum Arabic). In addition, flexural strength increased at 28 days from 2.7 N/mm2 for the control mix to 3.54 N/mm2 with gum Arabic at 0.8%. Thus, the addition of 0.8% gum Arabic by weight of cement to sisal fibre-reinforced concrete improves the workability of concrete mix and increases the strength of the concrete. Therefore, gum Arabic identified as a dispersant of sisal fibres can encourage the increased use of sisal fibre at high percentages and will offer potential for the development of low-cost construction materials.
Keywords: workability, sisal fibre, gum Arabic, balling effect, reinforced concrete
