[01] Bruce Roy Thulane Vilane, Department of Agricultural and Biosystems Engineering, Faculty of Agriculture, University of Eswatini, Luyengo Campus, Luyengo, Kingdom of Eswatini. [02] Sanele Robert Mbingo, Department of Agricultural and Biosystems Engineering, Faculty of Agriculture, University of Eswatini, Luyengo Campus, Luyengo, Kingdom of Eswatini. [03] Shongwe Mduduzi Innocent, Department of Agricultural and Biosystems Engineering, Faculty of Agriculture, University of Eswatini, Luyengo Campus, Luyengo, Kingdom of Eswatini.

Calcium chloride admixture is used as an accelerator in the hydration process of cement, leading to increased rate of setting and substantial compressive strength development. Taking advantage of this admixture is paramount for maximizing its utility value in the construction industry, since compressive strength is considered as an integral property of concrete blocks in the construction and building fraternity. An experiment was conducted to determine the effect of calcium chloride admixture on the compressive strength of concrete blocks. It utilized a mix design of 1:5 (Cement: sand) which was the standard mix design used in the construction industry within the country. The mix design manipulation resulted in five treatments, which were the calcium chloride admixtures at proportions of T₁ (0%), T₂ (1%), T₃ (2%) and T₄ (3%) and T₅ (4%) including the control (T₁, 0%) on weight basis of the cement, with four replications. All concrete block specimen were cured for 28 days. Data analysis was conducted using one-way ANOVA in SPSS version 2.0 computer software. The results reflected that the optimum compressive strength (2.98 N/mm2) of the calcium chloride blended concrete blocks was achieved with 4% addition of calcium chloride. The compressive strength under T₅ (4% of CaCl₂) was 1.62 N/mm², 2.07 N/mm², 2.14 N/mm² and 2.98 N/mm² after 7, 14, 21 and 28 days, respectively. Treatment 4 (3% of CaCl₂), had the highest water absorption value (12.8%), while the control Treatment (T₁) had the lowest water absorption value (11.06%). It was concluded that an increase in the proportion of the calcium chloride added to the concrete mix design led to an increase in the compressive strength of the concrete blocks. It was also concluded that there was an increase in compressive strength of all the calcium chloride blended concrete blocks with an increase in the curing period, while it was concluded that there was an increase in the amount of water absorbed with an increase in the proportion of calcium chloride admixture in the specimen.

Calcium Chloride, Admixture, Compressive Strength, Concrete Blocks

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