Scientific and practical bases of increasing the durability of modified concrete on lightweight aggregates for thin-walled hydraulic structures
Journal Title: Вісник Одеської державної академії будівництва та архітектури - Year 2018, Vol 1, Issue 73
Abstract
It is shown that to improve the durability and mechanical properties of concrete on porous aggregates, technological operations are useful, which improve the joint action of the aggregate and the cement-sand matrix. In particular, there are operations that reduce the moisture deformations of the aggregate. Two methods of controlling the joint action of the aggregate and the matrix were proposed taking into account the specific conditions of operation of thin-walled structures of hydraulic structures. The first method is the preparatory treatment of gravel with a cement slurry in the initial stage of the preparation of the mixture, the second method is the hydrophobization of the gravel surface. These two methods in combination with effective modifiers and fiber make it possible to obtain expanded clay lightweight concrete with increased strength, water-tightness and frost-resistance. Concrete with strength up to 42…44 MPa, water-tightness from W6 to W12 and frost-resistance from F400 to F600 were obtained using S-3 superplasticizer, silica fume, fiber and preparatory treatment of gravel with a cement slurry. The average density of these lightweight concretes in the dry condition was from 1,650 to 1,700 kg/m3, and in the water-saturated condition from 1,800 to 1,870 kg/m3. At the same time, these concretes had greater strength and lower average density in a water-saturated condition, as well as lower moisture content during operation. Thus, the developed modified lightweight concrete is characterized by increased durability and can be used in thin-walled constructions of reinforced concrete floating structures. The use of lightweight concrete allows to increase the carrying capacity of reinforced concrete floating structures. Regulations on the technology for the preparation of modified shipbuilding expanded clay lightweight concrete and fiber-reinforced lightweight concrete for the manufacture of thin-walled floating structures and floating docks were developed and approved. Also, the draft State Standard of Ukraine «Shipbuilding Concrete. Technical conditions and technology of preparation» was developed and is now at the stage of discussion and coordination.
Authors and Affiliations
S. O. , Kroviakov
Keywords
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