Vibroformed dinas-quartzite refractory concrete parts

Abstract

Refractory concrete compounds, parts, and especially large concrete blocks play an important role in acceleration of scientific and technical progress in ferrous metallurgy [i]. In connection with this, an increase in the level of mechanization of production of silica concrete blocks as the most massive form of aprts produced by Khristoforov Refractory Block and Concrete Plant and Pervoural'sk Dinas Plant is a pressing problem.At present, in these plants silica concrete parts are produced by manual pneumatic ramming from semidry dinas-quartzite mixture [2]. The significant disadvantages of this method of production are low productivity, the impossibility of production of parts of complex configuration and thin-walled parts (the wall thickness is comparable to the thickness of the ramming heel), nonuniform compaction of concrete mixture within the limits of the whole block (as the result of layer-by-layer ramming), which in some cases leads to a layer structure, and the harmful action of vibration on the body.The method of formation of dinas-quartzite concrete parts with the use of paired rams reduces the vibration on the hand of the worker but does not eliminate the disadvantages of manual pneumatic ramming [2].Forming of concrete parts from semidry mixtures may be mechanized with the use of floating vibrocompaction [3]. The machine has not found use because of the impossibility of forming assembly loops and laying parts. One of the latest designs of a machine for mechanized ramming of blocks is the design of the Scientific-Research Institute for Mining [4]. A number of significant omissions were revealed in introduction of the machine in Khristoforov Refractory Block and Concrete Plant.Other methods of production of dense concrete blocks are also known [5-9] but for various reasons they are not used in production.In connection with the above, we have developed a method of mechanismed forming of dinas-quartz concrete parts* from semidry mixturest for parts of simple forms and from fluid mixtures for thin-walled parts and those of complex configuration.Below are considered the results of investigations related to development of the method of production of vibroformed dinas-quartzite concrete parts.A method of production of vibroformed parts of high-flow and liquid concrete mixtures with an increased water glass content (18-20%) is known [2]. However, the production of large concrete parts using this method is difficult since the formation on their surface in drying of the parts of a dense crust enriched with sodium silicate prevents migration to the surface of moisture evaporating from the inner portion of the part, which leads to formation of a damp core, deformation of the parts during drying, and a sharp reduction in their strength.