Potential of Urea Fertilizer (UF) as a retarding admixture in plain concrete

Abstract

In this study, the use of Urea fertilizer (UF) as a retarding admixture in plain concrete was investigated. Six different mixes of proportion 1:2:4: and a water/cement ratio of 0.5 with (0, 1, 2, 3, 4 and 5%) by weight of urea fertilizer dosage in the concrete mix was adopted. Concrete cubes of 150mmx150mmx150mm made from the mix proportion and dosage of urea fertilizer were cast, cured and tested after 7, 14 and 28 days. It was observed from the study that urea fertilizer acts as a retarder in concrete production. The workability increased as the content of the urea fertilizer in the concrete increased. The compressive strength of the concrete decreased as the content of the urea fertilizer in the concrete increased. The final setting time increased from 20 hours to 50 hours at 5% UF content. The compressive strength decreased by approximately 57% from the control value to the 5% urea fertilizer content. The optimum UF content for standard concrete works is 0.5% which will give a compressive strength of 24 N/mm²

Keywords: concrete, compressive strength, retarder, urea fertilizer, workability