Effects of Palm Kernel Shells (PKS) on Mechanical and Physical Properties of Fine Lateritic Soils Developed on Basalt in Bangangte (West Cameroon): Significance for Pavement Application  
[PERSON]  
1 Department of Earth Sciences, Faculty of Sciences, University of Dschang, Dschang P.O. Box 67, Cameroon; [EMAIL_ADDRESS] (V.H.N.D.); [EMAIL_ADDRESS] (I.F.T.)  
[PERSON]  
2 Department of Civil and Mining Engineering (SEBE), University of Namibia, Jose Eduardo dos Santos Campus, Ongwediva P.O. Box 3624, Namibia; [EMAIL_ADDRESS]  
[PERSON]  
1 Department of Earth Sciences, Faculty of Sciences, University of Dschang, Dschang P.O. Box 67, Cameroon; [EMAIL_ADDRESS] (V.H.N.D.); [EMAIL_ADDRESS] (I.F.T.)  
[PERSON]  
2  
Footnote 12: email  
The CBR is the most used parameter for the dimensioning of flexible pavements in tropical countries, and the bearing capacity of subgrade soil is important for the determination of the required pavement thickness [3; 14; 23; 24]. Many studies have been carried out on the improvement of geotechnical properties of clay-rich laterites for use as sub-base course materials for pavements [25; 26; 27]. These studies revealed that bitumen, cement, lime, and other hydraulic binders perform as good stabilizers of fine-grained soils with a resulting significant increase in the bearing capacities [6; 19; 26; 28; 29; 30]. Though these commonly used techniques are effective, they are still cost intensive and also have environmental challenges [2; 27; 31]. It becomes necessary, therefore, to adopt novel techniques to improve upon the mechanical characteristics so as to meet the relevant specifications [2; 22; 31]. Common applications of some innovative and lost-cost industrial waste materials (aluminum slag, crushed ceramic tiles, among others) for highway construction have been cited by [31; 32; 33; 34; 35; 36].  
In recent decades, a great number of alternative materials, for example, agricultural wastes such as coconut husks and shells, bamboo, corn cob, millet husk, palm kernel shells (PKS), and other fibers, have been introduced and used to optimize the properties of fine-grained lateritic soils [37; 38; 39; 40]. It has been found from some of these studies [41; 42; 43] that the addition of bio-materials has shown positive effects in the improvement of some of the geotechnical characteristics of soils (decrease in liquid limit, plasticity index, soil permeability, swelling index and shrinkage limits, increase in CBR, unconfined compressive strength (UCS), maximum dry density) without adversely impacting the environment. More specifically, ref. [44] showed the use of pulverized PKS for road construction. Furthermore, ref. [45] revealed that PKS possesses excellent CBR potential to be used as a litho-stabilizer, and [44] showed that pulverized palm kernels induced a reduction in optimum moisture content (OMC) and an increase in soaked CBR and UCS values for stabilized soils. In Bangangte, an area in Western Cameroon, fine laterites are found associated with a thick lateritic cover derived from weathering and lateritization of basaltic rocks [46]. In recent years, the socioeconomic development has favored the construction of many main and secondary roads in this area. However, the materials used often come from other localities, with the use of local materials being accompanied by many structural failures. One consequence is, therefore, the high cost of road projects. In the meantime, there are no geotechnical studies of these abundant local materials. Thus, this paper firstly aims to provide the physical, mechanical, and mineralogical properties of fine laterites from two soil profiles in Bangangte. Secondly, this paper focuses on producing innovative and low-cost material of acceptable bearing capacity for pavement application with PKS as a partial replacement for fine laterites. Based on the results obtained from this study, the contribution of an agricultural waste in the stabilization of fine laterites for road construction projects has been evaluated.