Effect of Black Liquor from Date Palm on the Workability and Compressive Strength of Portland Cement and Concrete

Lignin is the second most abundant natural polymer. Due to the high content of carbon and hydrogen (C-H, C-C, C=O), it can be used as a potential dispersant for cement matrix. The objective of this study is to extract lignin from date palm and study its effect in the form of black liquor (BL) on the rheological and physic-mechanical properties of the cements and concrete. The lignin in black liquor form represents approximately 30 wt% dry weight of date palm. It is a heteropolymer composed primarily of methoxylated phenylpropylene alcohol monomeric units interconnected by a variety of stable carbon-carbon and carbon-oxygen-carbon (ether and esters) linkages. The results found show the positive effect on the workability of cement and concrete and confirms its dispersion effect by improving compressive strength of concrete during the early and the later ages of hydration.