Cement stone modified with complex of polycarboxylate superplasticizer and silica fume

Recently, the issue of concrete durability of reinforced concrete structures and constructions, especially those used in harsh climatic conditions, has become very important. Present approaches to the formation of durable concrete involve the use of active mineral additives with modern superplasticizers based on polycarboxylate ethers. The review of literature showed that there are little data available on the effect of polycarboxylates on hydration and hardening of cement stone. It is assumed that polycarboxylate superplasticizers can be absorbed in a dense layer on the surface of cement grains and, in some cases, intercalate into neoformations. The article considers the peculiarities of how the microstructure of hydrated phases of cement stone with a complex admixture of silica fume and polycarboxylate superplasticizer is formed. It has been established that silica fume promotes the formation of predominantly low-basic hydrated phases of C-S-H (I) type in cement stone. Introduction of the complex reduces the content of calcium hydroxide in cement stone and forms a structure of amorphized low-basic calcium hydrosilicates, resistant to various environmental effects.