Investigating the Effect of Bamboo Fibers on The Engineering Properties of Laterite Soils in Road Construction.

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Kabale University
The growing cost of conventional stabilizing agents and the need for the economical utilization of industrial and agricultural wastes for beneficial highway construction purposes encouraged the investigation into the stabilizing potential of bamboo fibre in lateritic soils. An experimental study was carried out on the natural and the modified lateritic soil classified as A-2-6(0) and clayey gravel (GC) according to AASHTO and Unified Soil Classification System (USCS) respectively. The samples were treated with 0 – 1.0 % (0.25 increment) proportions of bamboo fibres by dry weight of the soil. Test were carried out to determine the index properties and strength characteristics of the natural and treated soils respectively. Test results show that liquid limit decreases with increase in fibre up to 5% and increases with further increase, plastic limits decreased with increase in bamboo fibre content but rises at 1%, while the plasticity index (PI) decreased with increased bamboo fibre content up to 0.5%. Further increase in fibre content resulted in increase in PI. The specific gravity of soil–bamboo fibre mixtures did not take a definite pattern as it increases and decreases at varying bamboo fibre contents. Maximum dry density (MDD) increases with fibre contents at 0 - 0.75% from 1.923 – 2.207g/cm3 and 1.980 – 2.092g/cm3 for heavy and light compaction respectively and decreases with further fibre increment while the optimum moisture content (OMC) decreased continually for all compaction efforts with higher fibre contents from 15.7 - 10.2% and 12.6 – 9.8% for (0 – 1.0% fibre) respectively. Generally, soaked and unsoaked CBR increases from 15 to 25% and 20 to 29% (from 0 – 0.75%) and slightly decrease at 1%, while UCS of the treated soil increased from 1130 to 1460KPa at (0 - 0.50% fibre contents) and decreases with further increase in fibre content. The UCS – CBR developed relationship using Microsoft excel software 2013 were of the second order polynomial in the form, α₁x² - α₂x + c, at R² values of 0.89 and 0.97 for soaked and unsoaked conditions respectively indicating a high correlation between the CBR and UCS thus, can be used to predict the UCS at various CBR values and bamboo fibre contents in treated lateritic soils. Also the ANOVA analysis for effect of bamboo fibre on strength characteristics showed that in all cases, Fcal > FCrit indicating that the effects of bamboo fibre on lateritic soil were statistically significant. Based on the results, soil optimally treated at 0.75% bamboo fibre improved the soil and was recommended for use in construction of sub-base layer of road pavement.
Kiiza, Obed (2023). Investigating the Effect of Bamboo Fibers on The Engineering Properties of Laterite Soils in Road Construction. kABALE: Kabale University.