Study on Road Performance of Cement Fly Ash Stabilized Steel Slag-Concrete Recycled Macadam.

Hongbo Li,Yufei Tong,Xuanshuo Zhang,Hubiao Zhang,Junku Duan

doi:10.3390/ma14247530

Hongbo Li, Yufei Tong + Show 3 more

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https://doi.org/10.3390/ma14247530

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Abstract

In order to promote the application of steel slag in road engineering, improve its utilization rate and solve the environmental problems caused by its large accumulation, unconfined compressive strength (UCS) test, indirect tensile strength (ITS) test, freeze-thaw cycle test, dry shrinkage and temperature shrinkage test tests with different steel slag contents were carried out. And the strength formation mechanism of steel slag in base material was revealed by SEM. The results show that the strength of the mixture initially increased and then decreased with increasing steel slag content. The frost resistance increased with increasing steel slag content, which should be limited to no more than 75%. Increasing the steel slag content improved the drying shrinkage resistance but was not conducive to the temperature shrinkage resistance. Microscopic analysis shows that adding a suitable amount of steel slag generated a gel material that was distributed inside the pores. This increased the density of the hardened slurry structure, which improved the strength. The research can provide scientific basis for the application and promotion of steel slag in road base.

Highlights

Semirigid bases are the main form of road bases in China, and they offer the advantages of a high bearing capacity, moderate stiffness, and good slab properties
The results showed that replacing gravel with Steel slag (SS) resulted in a 7-d unconfined compressive strength (UCS) of greater than 9 MPa as well as good elastic deformation resistance
The physical and chemical properties of the raw materials were used to evaluate the mechanical properties, frost resistance, and crack resistance of five SS–concrete-recycled macadam (CRM) mixtures stabilized with cement and fly ash according to the SS content

Summary

Introduction

Semirigid bases are the main form of road bases in China, and they offer the advantages of a high bearing capacity, moderate stiffness, and good slab properties. The rapid development of China’s highway engineering industry has led to serious overexploitation of natural gravel, which has caused irreversible environmental damage. Thanks to the government’s increasing emphasis on protecting the environment, China has explicitly banned the exploitation of natural gravel, which has resulted in shortages of stone for road construction and price increases. Steel slag (SS) is an industrial waste product of the steelmaking process and accounts for 15–20% of the crude steel output [5]. The amount of SS produced has increased by millions of tons each year, but the utilization rate is less than 20% in China [6].

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