Stabilization of Gap-Graded Mix Using Oil Mesocarp Fibre as Additive

Abstract:

Purpose: The study used oil palm mesocarp fibre as an additive in gap-graded mix for the purposes of stabilization. The oil palm mesocarp fibre functions as reinforcement in the mix, providing additional tensile strength in the resulting composite whilst serving as an economic and efficient disposal of the oil palm fibre, which is a waste, generated from oil palm production.

Method: A Controlled Sample Mix (CSM) was prepared according to the Marshall procedure specified in ASTM D1559 and compared with Gap-Graded Mixes (GGM). The mix content i.e. Optimum Binder Content (OBC) for CSM and Optimum Oil Palm Mesocarp Content (OPMF) for GGM were from the Marshall Method. The CSM binder content of variations, 6, 6.5. 7, 7.5, 8% and fibre content in the GGM, from 0.1, 0.2, 0.3, 0.4, and 0.5% were used in the mixes. The mesocarp fibres were cut into small pieces (10-15 mm) and added directly to the aggregate sample in different proportion.

Results: The results plotted for Unit weight, Stability and Air content gave the OBC as 6.83% and a 0.22% OPMF at that determined OBC.

Conclusion: The stability values obtained from the Marshall Test showed the strength of the gap-graded mix (GGM) was lower than the strength of the controlled sample mix (CSM). However, the flow values were lower in the CSM as compared to the GGM specimen, which is an indication of a better resistance to deformation under sustained loading.