THE EVALUATION OF PALM KERNEL SHELLS AS COARSE AGGREGATES FOR RIGID PAVEMENT IN A COASTAL REGION, NIGERIA

Abstract

This paper presents the rationalization of the use of palm kernel shells as coarse aggregates for rigid pavements in the coastal region of Nigeria where aggregates are in short supply and palm kernel waste dumps abound, whose disposal constitutes environmental pollution and health hazard. Index and mechanical tests were carried out on samples of palm kernel shell wastes derivable in large quantities in the coastal and forested areas of the southern parts of Nigeria in accordance with relevant European standards. The appropriateness of the resulting nominal mixes of the 'palm kernel shell concrete for rigid pavement was evaluated accordingly at both fresh and matured ages. Also, a cost model, in respect of the haulage distance from the Nigerian coastal region for the granitic coarse aggregates was developed. The results show that palm kernel shell is a lightweight aggregate. Of all the seven index properties evaluated, the Nigerian palm kernel shell satisfies only density criterion for normal concrete but adequate for lightweight. The cost model developed is linear with characteristic slope and intercept values of -117.2N/km and N4706 respectively and at R2 value of 0.855. The palm kernel shell concrete is marginally appropriate as rigid pavement at a nominal mix of 1:11/2:3.