Full Length Research Paper

Impact of clay particles on concrete compressive strength

Twubahimana Joseph Désiré1 and Mbereyaho Léopold2


Aggregates are one of the components of concrete that have properties to be fulfilled before being used. The cleanliness of the aggregates is required by all the standards of construction. Among the undesirable matters in the aggregates, there is clay. This study investigates the impact of clay particles on compressive strength of concrete. The tests have been conducted on the most used concrete constituents in Rwanda. The properties of concrete containing clay properties were assessed in civil engineering laboratory. The specimens used for compressive strength were cylindrical. All test specimens were prepared in accordance with ASTM 192-00. The specimens were cured continuously in limewater after the initial 24-hour moist cure period until the time of testing. The control cylinders were moved into the saturated lime water bath after initial 24-hour moist curing under wet burlap and plastic sheeting. For all concrete strengths studied in this research the specimens were tested at the age of 3, 7, 14 and 28 days. The clay quantities in aggregates which have been considered in this study are 1%, 3%, 5%, 7% and 10% by weight. For all these clay quantities, the quantities of water and cement have not been changed, and the all results were compared to the properties of concrete which does not contain clay particles. It was found that the concrete strength is inversely proportional to the quantity of clay particles contained in aggregates.

Key words: Concrete compressive strength, concrete testing, sand, gravel, cement clay particles.

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