A comparison study of the mechanical properties and drying shrinkage of oil palm shell and expanded clay lightweight aggregate concretes

• An OPS grain is much stronger than expanded clay.
• Better mechanical properties of OPS concrete than that for expanded clay concrete.
• Efficiency factor of OPS concrete is more than expanded clay concrete.
• Significant effect of partial early curing on compressive strength of OPS concrete.

For making artificial lightweight aggregate, selected raw materials are fed into a rotary kiln at high temperature. Providing such a high temperature is costly and generally, the process of making artificial lightweight aggregate is not environmentally friendly. The use of natural lightweight aggregate for making lightweight concrete can lead to low-cost construction. The use of a solid waste lightweight aggregate namely oil palm shell (OPS) as coarse aggregate, is not only environmentally friendly but leads to a low-cost material. This study is a comparison between some engineering properties of OPS lightweight concrete and an artificial lightweight (expanded clay) concrete with low water to cement ratio, along with having good workability and without any segregation. The test results show that OPS concrete has better mechanical properties and a higher efficiency factor than expanded clay lightweight concrete. The ceiling strength of expanded clay lightweight concrete occurs at an early age; while it happens in OPS concrete at a later age. The crack pattern of the tested specimens shows that OPS is much stronger than expanded clay. On the other hand, the compressive strength of OPS lightweight concrete is more sensitive to lack of curing. Although OPS lightweight concrete shows twice the amount of drying shrinkage than expanded clay lightweight concrete in the short term, this difference reduces significantly at later ages.