Microtexture Performance of EAF Slags Used as Aggregate in Asphalt Mixes: A Comparative Study with Surface Properties of Natural Stones

Rosolino Vaiana,Vincenzo Gallelli,Filippo Balzano,Teresa Iuele

doi:10.3390/app9153197

Abstract

Steelmaking industries produce a large amount of solid wastes that need to be adequately managed in order to ensure environmental sustainability and reduce the impact of their disposal on earth pollution. Electric arc furnace (EAF) slags are those wastes deriving from secondary steelmaking production; these slags can be re-used and recycled in many industrial applications such as the production of asphalt mixes. In this paper authors investigate the surface performance of EAF slags used as second-hand aggregate in asphalt mixes. In particular, slags behavior under polishing is compared to other types of aggregate commonly used for asphalt concrete such as limestone, basalt, and kinginzite. Several devices (skid tester, laser profilometer, polishing machine) were used to collect experimental data; the analysis of microtexture was carried out by comparing aggregate surface performance before and after polishing. Results show that EAF slags are positively comparable to basalt as concerns the polishing behavior; good correlations between skid resistance and some microtexture indicators are also carried out.

Highlights

Metallurgical industry is one of the world’s largest contributors to the anthropogenic CO2 emissions
In the light of the above, this paper focuses on the evaluation of electric arc furnace (EAF) slags usability as aggregate
In the light of the above, this paper focuses on the evaluation of EAF slags usability as aggregate in asphalt concrete

Summary

Introduction

Metallurgical industry is one of the world’s largest contributors to the anthropogenic CO2 emissions. Until the last years of 19th century, most of the produced steel derived from the integrated process (blast furnace, BF/basic oxygen furnace, BOF route) used coal as the reducing agent and iron as raw material [1]. In order to reduce energy consumption and bring CO2 emissions close to zero, a secondary production route using an electric arc furnace (EAF) is becoming far more widespread. By 2060, the share of secondary steel production will exceed the share of the primary one. In the secondary steelmaking process electricity is used to melt iron scraps with chemical additives into steel. Even if the secondary production route requires 56%

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Conclusion