Effect of Armocel - 200 Admixture on the Compressive Strength and Workability of Normal Concrete

Abstract

This study centered on the determination of the compressive strengths of concrete when 0%, 0.4%, 0.8%, 1.2% and 1.5% of Armocel 200 admixture was added per 50kg of cementitious material. A total of 75 cubes of 150mm size were cast, 15 each for the different percentages of the admixture. Three cubes each from the different mixes were crushed at 1, 3, 7, 14 and 28 days. The aggregates used were analyzed for specific gravity and particle size distribution. Slump test was carried out on the fresh concretes. Results obtained showed that the addition of Armocel 200 admixture increased the workability of the concrete. Moreover the compressive strength of the concrete increased with the increase in the dosage of the admixture up to 0.4% at all the days of curing. However, at 0.8% dose of the admixture a reduction in strength was observed. A further strength increase was also observed with a further increase in the dosage of the admixture.

Introduction

Background:
Concrete is a widely used construction material available in various types. Admixtures—chemical or mineral additives—are incorporated into concrete to improve properties like workability, strength, setting time, and durability.

Problem Statement:
Achieving good concrete strength requires a low water-cement ratio (≤0.6), which often reduces workability, causing practical difficulties in mixing, transporting, and placing concrete. Increasing water content to improve workability weakens concrete. Therefore, admixtures are necessary to maintain workability while keeping water-cement ratio low, but the optimal dosage needs investigation to balance strength and workability.

Objectives:
The study aims to investigate the effects of varying percentages of Armocel 200 admixture on concrete’s workability, compressive strength, and density. It also includes particle size analysis of aggregates and compares concretes with and without admixture.

Significance:
Findings will benefit the construction industry by optimizing admixture use to produce high-strength, workable concrete cost-effectively, enabling faster project completion.

Literature Review:
Plasticizers and superplasticizers improve concrete flow and strength without increasing water content. Superplasticizers reduce water demand, improve slump, early strength, and workability but their effects last only about 30 minutes. Various types exist with different chemical compositions.

Materials and Methods:
Materials used included Portland Limestone Cement, sharp sand, crushed granite, potable water, and Armocel 200 admixture (a sulphonated naphthalene formaldehyde-based set accelerator). Admixture dosages ranged from 0% to 1.5%. Aggregates underwent sieve analysis and specific gravity tests. Workability was measured by slump test, and compressive strength was tested on 150mm cubes cured in water, tested at intervals up to 28 days.

Results:
Sieve analysis showed well-graded aggregates suitable for concrete, with fine aggregates ranging from 75μm to 4.75mm and coarse aggregates from 4.75mm to 19mm.

Conclusion

A. Conclusion Based on the results of the study conducted, the following conclusion can be made: 1) For a given mix proportion, the compressive strength of the control and that of the admixture increased considerably with age. 2) When 0.4% of the admixture was added, the compressive strength of the concrete increased considerably above that of the control in days 1, 3, 7, 14 and 28. 3) At the addition of 0.8% admixture, the compressive strength of the concrete decreased below the control at day 1, 3, 7 and 14. 4) At the addition of 1.2% and 1.5% admixture, the compressive strength further increased above that of the control. 5) The slump increased correspondingly with increase in the percentage of admixture added, showing greater workability than the control. 6) The highest density was recorded at 0.8% admixture at 28 days. B. Recommendations Based on the results of this research, the following recommendations were made: 1) The use of Armorcel admixture should be highly encouraged in concrete production in order to achieve the higher strengths desired. 2) The recommended doses of the admixture by the manufacturer should strictly be adhered to in order to achieve the required result. 3) The workability of concrete enhanced with the addition of admixture with constant water/ratio. However, the rate of increase diminishes with its addition beyond 0.4 % of admixture dosage. This factor needs to be investigated in future, to determine optimum dosage of admixture if water/cement ratio is maintained at constant value. 4) Further research should be carried out on the compressive strength of concrete using another types of admixture to really confirm its behavior compared to the Armocel 200 admixture. 5) Further investigation should be carried out on other mix proportions and water/cement ratios to confirm the results of this investigation.

References

[1] Golaszewski, J., and Szwabowski, J. 2004. Influence of superplasticizers on rheological behaviour of fresh cement mortars. Journal of Cement and Concrete Research, 34(2), 235–248. [2] Han, V., Ros, S., and Shima, H. (2013). “Effects of sand content, superplasticizer dosage, and mixing time on compressive strength of mortar.” ACI Materials Journal, 110(1), 23–31. [3] Hsu, K.C., Chiu, J., and Tseng, Y.C. 1999. Effect of addition time of a superplasticizer on cement adsorption and on concrete workability, Cement & Concrete Composites, 21, 425-430. [4] Khatib, J.M., and Mangat, P., S. 1999. “Influence of superplasticizer and curing on porosity and pore structure of cement paste”. Cement and Concrete Composites, 21(5), 431–437. [5] Masahiro, O., Makoto, H., and Okamura, H. 2007. Effect of Superplasticizer on Self Compactability of Fresh Concrete. Journal of the Transportation Research Board, 1574, 37-40. [6] Ramachandran, V.S. 1995. Concrete Admixtures Handbook: Properties, Science & Technology. ed. 2. [7] Yamada, K., and Hanehara, S. 2001. Interaction mechanism of cement and superplasticizers - The roles of polymer adsorption and ionic conditions of aqueous phase. Concrete Science and Engineering, 3(11), 135-145. [8] Yaqub, M. and Imram Bukhari (2006). Effect of Size of Coarse Aggregate on Compressive Strength of High Strength Concrete. University of Engineering and Technology Taxila, Pakistan, 31st Conference on our World in Concrete and Structure: 16-17, August, 2006, Singapore. [9] The authors wish to acknowledge Mr. Precious Emmanuel Effiong (Asst. Project Manager, Amorsil West Africa, 31A Emina Crescent, Ikeja, Lagos) for giving us the Armoceladmixture to experiment on.

Copyright

Copyright © 2025 Dr. Udeme Hanson Iron, Dr. Abidemi Ilori, Udofia Odudu Ukere. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.