Effects of Admixture Sika on the Resistance of Different Types of Cement Used for Ordinary Concrete in the North West Region of Cameroon

Abstract

When concrete fails to perform its functions with its natural four ingredients sand, cement, gravel and water, admixtures are added to improve on its performance (less than 5% of the mass of cement). These admixtures have, a general rule to modify the properties of concretes, mortars or grouts, in the fresh and hardened state (to decrease the E/C ratio, to improve the workability, to reduce the dosage of cement, to increase the mechanical strength, change the setting and hardening time, improve the permeability and modify some particular properties). Sika, being the most common admixture in our milieu, the objective of this research is to study the influence of SIKA admixture especially the super plasticizer/high water reduction on the resistance of ordinary concrete in the context of North-West region of Cameroon because most concretes do not give the intended resistance. To achieve this goal, we used the most available super plasticizer in the region SIKAVISCOCRETE – KRONO 20, with 2 different dosages (0.5% and 0.8%) within the range of the proposed dosage; and 2 different brands of cement are used with the same resistance class (DANGOTE and ROBUST). The objectives were to study the workability of fresh concrete with the incorporation of a super plasticizer, the compressive and tensile strength of hardened concrete after 3days, 7days and 28days. The results of this research showed that relative to the control concrete without admixtures, the super plasticizer improved the workability of concrete with an increase of respectively 54.4% and 138% with DANGOTE cement and 23.3% and 73.33% with ROBUST cement. The compressive strength and tensile strength of concrete, using the both types of cement also increased with the dosage of super plasticizer SIKA. With the highest dosage of SIKA (0.8%), the compressive and tensile strength of adjuvanted concrete compared to the control concrete is respectively 20.10% at 28 days in compressive strength with ROBUST and 22.87% at 28 days with DANGOTE; and 17.07% at 28 days of tensile strength with ROBUST and 10.50% at 28 days with DANGOTE. The more the dosage of the super plasticizer is high, the more the concrete is workable and resistant. The cement ROBUST is more resistant than DANGOTE when incorporating super plasticizer. And we note that the resistance of ordinary concrete with both cements increase over time.

Keywords: SIKA; cement; admixtures, concrete; super plasticizer

DOI: 10.7176/CER/17-2-05

Publication date: December 31st 2025