This paper presents the results of an experimental study aimed at evaluating the effectiveness of mineral admixtures in suppressing the alkali–silica reaction (ASR) in concrete, which is one of the main causes of internal deterioration and reduced durability of reinforced concrete structures operated under humid conditions. The relevance of the study is due to the need to develop effective technological solutions that ensure the stability of the microstructure of cement stone and increase the service life of concrete structures, especially bridges, hydraulic engineering and infrastructure facilities. In the preparation of concrete, Khalaktyrsky sand (Kamchatka Krai, Russia) was used as fine aggregate. This sand contains an increased amount of reac-tive silica capable of reacting with the alkalis of cement, indicating a high probability of alkali–silica reaction (ASR) development in the absence of corrective admixtures. To reduce the intensity of ASR, the influence of two pozzolanic admixtures was investigated: silica fume (MKU-85) and the organomineral modifier MB2-50S, which represents a composition of silica fume and fly ash. The tests were carried out using an accelerated method regulated by GOST 8269.0, involving measurements of the relative linear expansion of fine-grained concrete specimens stored in an alkaline environment at a temperature of (80 ± 2) °C. The results showed that silica fume exhibited the strongest inhibiting effect: at a dosage of 15% by mass of cement, the measured ex-pansions decreased below the limiting level (0.1%) and stabilized, allowing the mixture to be classified as non-reactive. The MB2-50S modifier also demonstrated the ability to reduce the reaction intensity and improve the long-term stability of concrete behavior; however, its effectiveness was lower compared with silica fume. At the same time, increasing the content of MB2-50S above 15% may significantly enhance its inhibiting activity, making this admixture an economically justified alternative when adjusting the dosage.
Alwahed et al. (Thu,) studied this question.