Strength And Microstructure Of Lateritic Concrete Containing Palm Kernel Shell (Pks) As Partial Replacement For Coarse Aggregates.

ABSTRACT

This research work reports the investigation carried out to determine the strength and

microstructure of lateritic concrete containing palm kernel shell (PKS) as partial .

replacement of coarse aggregates. The study employed different mix proportions,

which resulted in casting and testing 148 cubes at 7, 14, 21, 28, 60, and 90-days of

curing, to determine the best and economic proportion that will give compressive

strength. The materials and methodology phase of this research evaluated the physical

and mechanical properties of aggregates, fresh concrete properties such as slump,

mechanical properties of hardened concrete, such as, compressive strength and

density, sorptivity and the microstructural properties of concrete. In the study of the

physical and mechanical properties of the aggregates, it was revealed that the PKS

aggregate exhibited low specific gravity, bulk density, impact, and abrasion value of

1.33, 661 kg/m3, 0.6% and 0.85% as compared with granite 2.74, 1660 kg/m3

, 0.98%

and 1.97% respectively. While, the laterite aggregate exhibited low porosity, bulk

density and specific gravity value of 11.39%, 1220 kg/m3 and 2.18 as compared with

sand 25%, 1786 kg/m3, and 2.76 respectively. The concrete specimen were produced

with PKS and granite as coarse aggregate, laterite and ordinary river sand as fine

aggregate and ordinary Portland cement as binder. Mix ratio of 1 :2:4 and water cement

ratio 0.5, were used in the concrete production. The 28-day compressive strength of

the concrete produced in this study was found to satisfy the minimum strength

requirements of structural concrete based on BS 8110 at 0% - 10% PKS content. The

result obtained and the observations made from the sorptivity test indicated that the

increase in PKS content increased the sorptivity of the concrete proportionally, which

is disadvantageous to concrete, especially in marine or water prone environment. The

SEM/EDX result indicated that inclusion of PKS in the concrete affects the bonding

between the binding medium and the aggregates such as, granite and sand. While, the ·

EDX result showed that the concrete contained elements such as calcium, alumina,

silica, oxides and sulphur. It is concluded that PKS aggregates can be used in the

production of lateritic concrete at 0% - l 0% respectively, but further increase in PKS content would negatively affect the concrete's strength.