Sucrose and Lignosulfonate Acid: Which One is More Effective as a Concrete Setting Retarder?

Abstract

The goal of this study is to experimentally evaluate the performance of sucrose and lignosulfonate acid as a concrete retarder. The initial and final setting times of concrete are obtained for various dosages of those admixtures. Besides, the impact of those retarders to the compressive strength of concrete is also explored. A total of 13 (thirteen) mix samples are made, in a laboratory, by adding various dosages of those admixtures into the reference mixtures. Those samples are tested using a concrete mortar penetrometer and a compression-testing machine to obtain their setting times and compressive strengths. Sucrose addition with a dosage of 0.01%, 0.014%, and 0.019% (by weight of cement) increases the initial setting time by 102.67%, 117.54%, and 138.89% and extends the final setting time by 57.70%, 72.83%, and 99.47%. The addition of liquid lignosulfonate acid by 0.6% (by weight of cement) causes the initial setting time to grow by 68.77% from 4.46 to 7.52 hours. Similarly, the final setting time is prolonged by 51.65% from 7.27 to 11.02 hours. This study confirms that sucrose is more effective than lignosulfonate acid in term of retarding concrete setting. However, careful attention is needed when applying sucrose as a set retarder because applying larger than a critical dosage results in an adverse effect. Sucrose is also an effective strength reducer for concrete. The 28-day strength reduces by 10 to 25% due to adding sucrose as much as 0.019% (by weight of cement).