O. Dvorkin

Bio: O. Dvorkin is an academic researcher. The author has contributed to research in topics: Silica fume & Reinforced solid. The author has an hindex of 2, co-authored 3 publications receiving 30 citations.

Using granite siftings for producing vibro-pressed fine-grained concrete

Abstract: Using stone crushing waste products allows more rational and complex use of mineral resources and increases the ecological safety level of quarry works and production of stone materials. This paper focuses on an experimental investigation of the composition effect of vibro-pressed fine-grained concrete incorporating granite siftings on compression and flexural strength. Analysis of regression equations, obtained using mathematical experiments planning, shows that dust particles included in the siftings can behave as micro-filler. This is especially the case at low cement-water ratios therefore yielding an increase in concrete strength. The positive effect of the dust fraction in siftings decreases as the cement-water ratio and the fineness modulus of sand that is a part of the aggregate become higher. The hardening kinetics of vibro-pressed concrete with granite siftings is analyzed. The results of the present study may be used for preliminary assessment of granite sifting efficiency as aggregates in vibro-pressed concrete and design of their optimal compositions.

Review of high and ultrahigh performance cementitious composites incorporating various combinations of fibers and ultrafines

Abstract: The outcomes of the research in modern cementitious composites have paved the way for their wide use in construction industry. The introduction of short, discontinuous and randomly distributed fibers to these composites has altered their inherent brittleness. Extensive research has been carried out on the effects of using of mono-fibers in a cementitious composite. However, limited reports in the approachable references on the use of hybrid fibers are available. The synergetic interaction between hybrid fibers have beneficial impact on cementitious composites. The incorporation of micro- and nano-pozzolanic materials, such as fly ash and silica fume have been used to develop high performance cementitious composites such as reactive powder concrete, DUCTAL and CEMTEC multiscale. Further developments were recently achieved by the development of ultra-high performance cementitious composites. The matter of developing high and ultrahigh cementitious composites using various kinds of fibers and particles has received enormous attention from the scientific community. This paper presents a comprehensive critical literature review on the area of high and ultra-high performance cement-based materials.