CONCRETE

[:ru]Рояк Г. С.[:en]Royak, G.[:] [:ru]д.т.н., проф., АО ЦНИИС Научно-исследовательский институт транспортного строительства[:en]DSc in Engineering, Professor, SC TSNIIS Research Institute of Transport Construction[:]

[:ru]Грановская И. В.[:en]Granovskaya, I.[:] [:ru]к.т.н., АО ЦНИИС Научно-исследовательский институт транспортного строительства[:en]PhD in Engineering, JSC TSNIIS Research Institute of Transport Construction[:]

[:ru]Тарасова А. Ю.[:en]Tarasova, A. Yu.[:] [:ru]канд. техн. наук, ЦНИИС, Россия[:en]Cand. Eng. Sc., CSRIC, Russia[:]

[:ru]Добкин В. С.[:en]Dobkin, V. S.[:] [:ru]инж., ОАО ЦНИИС[:en]engineer, OJSC “Central Scientific Research Institute of Construction”[:]

[:ru]Миленин Д. А.[:en]Milenin, D. A.[:] [:ru]инж., Научно-исследовательский институт транспортного строительства, Москва, Россия[:en]Eng., Research Institute of Transport Construction, Moscow, Russia[:]

Alitinform №4-5 (16) 2010 г. 46-53 стр.

Abstract

Portland cement for bridges concrete with grade 500 D0-N (GOST 10178-85*), which is successfully used for transport structures construction, was developed in 1980s. The cement contains no mineral admixtures (puzzolanic) and ensures preset properties of concrete by strength, frost resistance, water impermeability of monolithic and prefabricated constructions. One should recognize it reasonable to use micro-fillers for concrete manufacturing, in order to reduce thermal stress in concrete of monolithic and prefabricated constructions in course of their hardening. Micro-fillers, such as fly ash, slag and finely ground quartz sand have bigger specific surface area and smaller size of particles than cement, therefore when hardening less heat is emitted, quantity and development of micro-cracks in concrete are decreased.

Two technological trends are developed for manufacturing transport structures. The first trend concerns production of flowing concrete mixes with micro-fillers, efficient superplasticizers and other chemical admixtures ensuring self-compaction of concrete mixes without vibration, and providing predetermined properties of reinforced concrete structures.

The second trend supposes the use of finely ground sand with low water/solid ratio, vibropressing, use of rejection for coarse filling aggregates application, which leads to considerable improvement of the concrete homogeneity and quality.