Strength and Strain Properties of Concrete, Comprising Filler, Produced by Screening of Waste Crushed Concrete

Abstract

The presented paper is dedicated to the topical issue of utilization of screenings waste crushed concrete, which is produced as a result of crushing of waste materials, formed during dismantling buildings and facilities, and a production of fine aggregate concrete on its basis. The paper presented analysis of economic situation in the region and results of the study of screened waste materials in order to increase efficiency of an application of that product as fine aggregate and fine-ground active filler for a production of fine aggregate concretes.Particle size distribution, mineral and chemical composition of waste crushed concrete were studied, as well as features of their structure, taking into account heterogeneity of crushed material. Transitional zone of secondary aggregate and cement matrix was studied and it was proved, that the strength of adhesion with cement matrix of grains of that kind of secondary material, produced from screenings of waste crushed concrete, is significantly higher, than strength of the grain itself, which is indicative of an active influence of that aggregate on a formation of both characteristics of structure of cement matrix and dense transitional zone between them.Optimal composition of multicomponent binders, comprising fine-ground filler, produced from screenings of waste crushed concrete, is designed. Compositions and properties of cement matrix based on the designed binders are studied. Compositions of concretes, based on multicomponent binders with anthropogenic filler, are obtained and their strength and strain properties are studied.

Utilization of Cement Kiln Dust in Production of Alkali-Activated Clinker-Free Binders

“…As noted earlier [4,[20][21][22][23][24], reuse of dust from electrostatic precipitators in the technological cycle is not reasonable, since chemical analysis confirms the presence of alkali metals, the content of which, according to GOST, is strictly limited to not more than 0.67%. Moreover, addition of aspiration dust to the raw material mixture leads to the sludge thickening, which complicates its transportation to the feeders of rotary kilns.…”

“…Therefore, this paper presents a practicable method of cement kiln dust utilization to obtain alkali-activated clinkerfree binders and concretes based on these. These methods could be developed since a cement plant in the Chechen Republic has been operating since 1974, and Portland cement clinker is burnt in two rotary kilns with a clinker productivity of 1200 tons per day [3,[21][22][23][24].…”

Water-Reducing and Plasticizing Additives for Highly Mobile Concrete Mixtures

“…Thus, according to the regulatory documentation, it is necessary to provide a set of stripping strength of concrete, including during winter concreting for floors 80% of the required for the project, for columns -50-60%. Modern chemical additives can provide a sufficiently high strength at an early age (1-3 days) without a significant increase in the cost of concrete itself [26][27][28][29][30][31][32].…”

Building Demolition Products as a Secondary Raw Material for High-Strength Concrete

“…In domestic literature [1][2][3][4][5][16][17][18][19][20][21][22], the coefficient Rpr / R for concrete of middle classes is usually determined by using the following relationship:…”