Performance of steel slag aggregate in asphalt mixtures in a hot desert climate

Excessive usage of non-renewable natural resources and massive construction wastes put pressure on the environment. Steel slags, the main waste material from the metal industry, are normally added in asphalt concrete to replace traditional aggregate. In addition, as a typical microwave absorber, steel slag has the potential to transfer microwave energy into heat, thus increasing the limited self-healing ability of asphalt mixture. This paper aims to investigate the microwave absorption potentials of steel slag and the effect of its addition on road performance. The magnetic parameters obtained from a microwave vector network analyzer were used to estimate the potential use of steel slag as microwave absorber to heal cracks. Meanwhile, the initial self-healing temperature was further discussed according to the frequency sweeping results. The obvious porous structure of steel slag observed using scanning electron microscopy (SEM) had important impacts on the road performance of asphalt mixtures. Steel slag presented a worse effect on low-temperature crack resistance and water stability, while high-temperature stability can be remarkably enhanced when the substitution of steel slag was 60% by volume with the particle size of 4.75–9.5 mm. Overall, the sustainability of asphalt mixtures incorporating steel slag can be promoted due to its excellent mechanical and microwave absorption properties.

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Expansion Level of Steel Slag Aggregate Effects on Both Material Properties and Asphalt Mixture Performance

Transportation Research Record Journal of the Transportation Research Board ◽

10.1177/0361198119835513 ◽

2019 ◽

Vol 2673 (3) ◽

pp. 506-515 ◽

Cited By ~ 6

Author(s):

Jamilla Emi Sudo Lutif Teixeira ◽

Aecio Guilherme Schumacher ◽

Patrício Moreira Pires ◽

Verônica Teixeira Franco Castelo Branco ◽

Henrique Barbosa Martins

Keyword(s):

Material Properties ◽

Mechanical Performance ◽

Early Stage ◽

Asphalt Binder ◽

Steel Slag ◽

Asphalt Mixture ◽

Asphalt Mixtures ◽

Mix Design ◽

Expansion Level ◽

Different Levels

The influence of steel slag expansion level on the early stage performance of hot mix asphalt (HMA) is evaluated. Initially, samples of Linz-Donawitz type steel slag with different levels of expansion (6.71%, 3.16%, 1.33%) were submitted to physical, mechanical, and morphological characterization to assess the effects of expansion on individual material properties. Steel slag was then used as aggregate in HMA to verify the effects of its expansion characteristics on the volumetric and mechanical performance of the asphalt mixture. Four different asphalt mixtures were designed based on Marshall mix design, using asphalt cement (pen. grade 50/70), natural aggregate (granite), and steel slag (in three different levels of expansion). The mechanical characteristics of the asphalt mixture were evaluated based on results from Marshall stability, indirect tensile strength, and resilient modulus testing. A modified Pennsylvania testing method (PTM) was also performed on the studied asphalt mixtures to verify the potential of asphalt binder film to minimize the expansive reactions of steel slag. It was observed that the level of steel slag expansion changes some of the material’s individual properties, which can affect the volumetric parameters of the mix design. The use of steel slag as aggregate in HMA also improves the mechanical properties of non-aged asphalt mixtures. Moreover, the expansive characteristics of this material could be minimized when combined with other asphalt mixture components.

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Study on Recycling of Steel Slags Used as Coarse and Fine Aggregates in Induction Healing Asphalt Concretes

Materials ◽

10.3390/ma13040889 ◽

2020 ◽

Vol 13 (4) ◽

pp. 889 ◽

Cited By ~ 4

Author(s):

Haiqin Xu ◽

Shaopeng Wu ◽

Hechuan Li ◽

Yuechao Zhao ◽

Yang Lv

Keyword(s):

Mechanical Property ◽

Dynamic Stability ◽

Induction Heating ◽

Steel Slag ◽

Ct Scanning ◽

Asphalt Mixtures ◽

Steel Fibers ◽

Fine Aggregate ◽

Self Healing ◽

Negative Impacts

Steel slag, a by-product of steelmaking, imposes lots of negative impacts on the environment. For alleviating negative impacts, more and more experiments have been carried out to explore the application possibility of steel slag. The purpose of this study is to explore the feasibility of steel slag being applied in induction healing asphalt concretes to replace coarse and fine aggregate. Surface texture and pore sizes of steel slag were firstly tested, and then steel slag and basalt asphalt mixtures modified with steel fibers were prepared. Moisture susceptibility, dynamic stability, mechanical property, thermal property, induction heating speed, natural cooling speed and healing property of the asphalt mixtures were evaluated. Results showed that steel slags had more obvious holes in the surface while the surface area is much larger than that of basalt. Furthermore, steel fibers and steel slag both have dynamic stability, and steel fibers contribute to increased moisture resistance while steel slag is not. Steel slag asphalt concrete showed better mechanical property and better capacity to store heating. Steel slag asphalt mixtures had a similar heating speed to basalt asphalt mixtures but a significantly slower cooling rate. Finally, the induction healing test and CT scanning test demonstrated that steel slag asphalt mixtures had a similar healing ability to basalt asphalt mixtures. It can be concluded that steel slags have the potential to replace the natural aggregates to be applied in induction heating self-healing asphalt concretes.

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