Strength and Ductility of Randomly Distributed Palm Fibers Reinforced Silty-Sand Soils

Abstract

This paper investigates the resultant strength and ductility behavior when randomly distributed palm fibers are used to reinforce silty-sand soils. The composite soils were tested under laboratory conditions and examined for unconfined compression strength (UCS), California Bearing Ratio (CBR) and compaction test. The results indicated that; the maximum and residual strengths, orientation of surface failures, ductility and the stress-strain relationship of the specimens were substantially affected by the inclusion of palm fibers. A significant result was the determination that the sliding failure strength controlled the failure of the specimens rather than the rupture failure strength. Overall it was found that reinforced soil using palm fibers as the primary reinforcement are beneficial engineering materials and could potentially be used more often, though additional field use and testing should be carried out. Given the current concern over the environment and greenhouse gas emissions, strengthening soil through the use of natural materials (in this case palm fibers) and the promotion of the cultivation of palm groves is one way that engineers and designers can contribute to a greener earth. Add to this the fact that the date palm is one of the most cultivated tree crops in the world with a worldwide distribution of around 100 million palms distributed in 30 countries including the Middle East, Asia, Africa, North America, Mediterranean countries and Australia in a bountiful resource that is available in many places where high technology engineering practices are either not available or too expensive. The use of the date palm for soil reinforcement means that in many areas of the world there is a readily available, effective local source of material for road foundation construction.

Effect of Random Inclusion of Polypropylene Fibers on Strength Characteristics of Cohesive Soil

“…Nagrale et al (2005) studied the improvement of CBR value of subgrade soil with inclusion of polypropylene fibers and concluded that 1.5% fiber with aspect ratio 100 and 84 would be the optimum quantity in clayey soil and fine sand respectively. Marandi et al (2008) studied the strength and ductility of fiber reinforced silty sand with palm fibers and concluded that palm fibers could be used as a reinforcing material in improving the strength and ductility characteristics of soil. Jadhao and Nagarnaik (2008) studied the influence of polypropylene fibers on the engineering behavior of soil fly ash mixtures by using different fiber lengths (6, 12 and 24 mm) in the range of 0-1.5% by dry wet of soil and observed that maximum improvement in strength was achieved at a fiber length of 12 mm with fiber content of 1%.…”

Target Reliability Approach to Study the Effect of Fiber Reinforcement on UCS Behavior of Lime Treated Semiarid Soil

“…Pavements constructed on reinforced subgrades have several advantages from economic, environmental and traffic safety point of view (Marandi et al 2008). It allows thinner road structures and prolonged life cycles, which lead to a saving in natural resources.…”

“…In fiber-reinforced uncemented soil, interactions occur at the interface between the fiber surface and the clay grains that play key role in the mechanical behavior. Marandi et al (2008) used natural palm fibers as soil reinforcement. Fiber contents used were 0.25%, 0.50%, 0.75%, 1.00%, 1.5%, 2.00% and 2.50% by dry total weight whereas the fiber lengths tested were 20 mm and 40 mm.…”

Influence of Agricultural Wastes on Shear Strength Properties of Soil

“…Findings show that coir fibre exhibits greater enhancements in the strength of soil by having higher coefficient of friction [12]. Coir retains much of its tensile strength when wet and it has low tenacity but the elongation is much higher [13] and as for palm fiber, a constant palm fiber length, with increase in fiber inclusion, the maximum and residual strengths were increased [14]. It is observed that the palm fibers act to interlock particles and group of particles in a unitary coherent matrix thus…”