Optimization of corrosion-resistant compositions concrete by type and consumption of additive modifiers for the conditions of the Republic of Burundi

Introduction. The results of a study on the influence of the type and dosage of plasticizing admixtures on the properties of fine-grained concrete operated under the conditions of the Republic of Burundi are presented. The object of the study is fine-grained concrete, while the subject of the study is the quality indicators of the concrete mix and hardened concrete. A distinctive feature of these studies is the use of raw materials sourced from the Republic of Burundi.

Materials and methods. The following raw materials were used: CEM II/V-P 32.5 M cement produced by BUCECO (Republic of Burundi), sand from the Muzazi River in the Republic of Burundi, and plasticizing admixtures from different manufacturers with various chemical compositions.

Results. It was established that the incorporation of the plasticizing admixtures GPM-U and GLENIUM 323 MIX provides a significant water-reducing effect on the cement system. At the same time, an improvement in the quality of the hardened cement paste was observed. The patterns identified for the cement paste were also observed for fine-grained concrete: the incorporation of plasticizing admixtures of any type makes it possible to densify the structure, reduce porosity, and increase the strength of the material. In turn, the increased density of fine-grained concrete ensures lower permeability and, consequently, greater resistance to aggressive environmental exposure. This is particularly important for the operating conditions characteristic of the Republic of Burundi.

Conclusions. As a result of the studies, the following conclusions and recommendations can be made: the optimal dosages of additives (regardless of their type) are within 0.9–1.2 % of the mass of cement (based on the value of the water-reducing effect). At the same time, additives based on polycarboxylate ethers give the greatest effect both on pure cement stone and on fine-grained concrete.

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