Keyword: «superplasticizer»

Securing dense concrete structure and the intensification of cement hydration processes plays an important role in ensuring high concrete strength. The results of the applicability of dunite magnesian rocks of Central Aldan (Yakutia) for concrete production are presented. Petrographic and thermographic studies are conducted for the preliminary preparation of the charge. Pre-firing, fine intergrinding, and additional mechanical activation of the charge were applied. It is found that finely ground and pre-fired magnesium silicates act as both a micro-filler contributing to increased stone density and an active agent in forming robust crystallization structure. It is established that the use of pre-fired dunite powder with specific surface area of 8000 ± 200 cm2/kg in combination with the SP-1 superplasticizer allows obtaining autoclaved reactive powder concrete with a strength grade of up to B45.

In this article, the authors outline the key principles of how various plasticizers function in concrete mixtures and describe the operating mechanism of polycarboxylate‑based plasticizers. The study then presents research findings on the impact of two types of polycarboxylate plasticizers – Linamix PK and Qz LS – on the plasticity kinetics of cement paste with a 15 % reduced water‑to‑cement ratio. Based on the obtained data, graphs were constructed showing the dependence of the penetration depth of the Vicat apparatus needle in the cement paste on time elapsed since the addition of mixing water. It was found that both plasticizers have a similar effect on the cement paste, but the Qz LS plasticizer demonstrates a longer‑lasting plasticizing effect on the cement paste over time.