Oil palm kernel shell (OPKS) is an organic lightweight aggregate (LWA) used as coarse
aggregate in tropical countries for concrete in low-cost buildings. Concrete mixture proportioning
is used to calculate the quantities of different constituents required to achieve
different properties. For LWA concrete with mineral aggregate, there exist mix design
methods that follow rigorous sequence of steps that consider performance specifications.
However, no such method exists for concrete using organic coarse aggregate, namely,
OPKS. The methods that exist for OPKS concrete that satisfy technical specifications for
structural lightweight concrete (LWC) are based on trial and error or empirical methods.
With trial and error method, it is not always possible to predict the value of specific properties
of the concrete; however, engineers are mainly concerned with obtaining specific
properties when proportioning a concrete mixture. The present topic presents a structured
method for trial mix proportioning of structural LWC using OPKS as coarse aggregate.
Based on the principle of the absolute volume method in ACI 213, the method is
presented, following the below headings: (1) properties of constituents of OPKS concrete;
(2) mix design procedure; and (3) results and discussion. Technicians in tropical oil-palmproducing
countries for low-cost buildings can use the presented method.
Keywords: lightweight concrete, mix proportioning, compressive strength, oil palm
kernel shell, Benin