scholarly journals Research on microwave heating performance of modified steel slag asphalt mixture

2021 ◽  
Vol 13 (4) ◽  
pp. 168781402199047
Author(s):  
Yanfang Song ◽  
Zhe Wang ◽  
Yan Zhou ◽  
Rong Hu

Aiming at the change law of the flexural and tensile strength of the modified steel slag asphalt mixture during microwave heating, the results of this paper are as follows: the microwave heating process can achieve the recovery of the flexural and tensile properties of the modified steel slag asphalt mixture. The number of point bending failure tests continues to increase, and the recovery rate of bending and tensile properties of beams made of modified steel slag asphalt mixture will slowly decrease until the test piece is completely destroyed. The flexural and tensile strength of beams made by microwave heating asphalt mixture cannot be fully recovered, but different asphalt mixtures have different recovery effects. Compared with the ordinary basalt asphalt mixture, the steel slag asphalt mixture before modification has the same bending and tensile repair effect after microwave heating, while the modified steel slag asphalt mixture has the first bending and tensile repair effect after microwave heating increased by 23%.

2014 ◽  
Vol 599 ◽  
pp. 193-197 ◽  
Author(s):  
Yi Han Sun ◽  
Quan Tao Liu ◽  
Shao Peng Wu ◽  
Fei Shang

In this research, the potential of using steel slag asphalt mixture as a self-healing material was investigated by means of microwave heating. The microwave heating rate and thermal conductivity of asphalt mixtures were tested respectively. The result shown that, the heating rate of steel slag asphalt mixtures is approximately two times faster than limestone asphalt mixtures. While its thermal conductivity is slightly lower. It is concluded that microwave heating can be used to promote self-healing of steel slag asphalt mixture.


Materials ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 146 ◽  
Author(s):  
Haopeng Wang ◽  
Yue Zhang ◽  
Yi Zhang ◽  
Shuyin Feng ◽  
Guoyang Lu ◽  
...  

Microwave heating is an encouraging heating technology for the maintenance, recycling, and deicing of asphalt pavement. To investigate the microwave heating properties of asphalt mixture, laboratory tests and numerical simulations were done and compared. Two types of Stone Mastic Asphalt (SMA) mixture samples (with basalt aggregates and steel slag aggregates) were heated using a microwave oven for different times. Numerical simulation models of microwave heating of asphalt mixture were developed with finite element software COMSOL Multiphysics. The main thermal and electromagnetic properties of asphalt mixture, served as the model input parameters, were measured through a series of laboratory tests. Both laboratory-measured and numerical simulated surface temperatures were recorded and analyzed. Results show that the replacement of basalt aggregates with steel slag aggregates can significantly increase the microwave heating efficiency of asphalt mixture. Numerical simulation results have a good correlation with laboratory test results. It is feasible to use the developed model coupling electromagnetic waves with heat transfer to simulate the microwave heating process of asphalt mixture.


Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7060
Author(s):  
Mohammad Alharthai ◽  
Qing Lu ◽  
Ahmed Elnihum ◽  
Asad Elmagarhe

This study investigates the substitution of conventional aggregate with a Florida washed shell in open-graded asphalt mixtures and evaluates the optimal substitution percentage in aggregate gradations of various nominal maximum aggregate sizes (NMASs) (i.e., 4.75, 9.5, and 12.5 mm). Laboratory experiments were performed on open-graded asphalt mixture specimens with the coarse aggregate of sizes between 2.36 and 12.5 mm being replaced by the Florida washed shell at various percentages (0, 15, 30, 45, and 100%). Specimen properties relevant to the performance of open-graded asphalt mixtures in the field were tested, evaluated, and compared. Specifically, a Marshall stability test, Cantabro test, indirect tensile strength test, air void content test, and permeability test were conducted to evaluate the strength, resistance to raveling, cracking resistance, void content, and permeability of open-graded asphalt mixtures. The results show that there is no significant difference in the Marshall stability and indirect tensile strength when the coarse aggregates are replaced with Florida washed shell. This study also found that the optimum percentages of Florida washed shell in open-graded asphalt mixture were 15, 30, and 45% for 12.5, 9.5, and 4.75 mm NMAS gradations, respectively.


Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 663 ◽  
Author(s):  
Baowen Lou ◽  
Zhuangzhuang Liu ◽  
Aimin Sha ◽  
Meng Jia ◽  
Yupeng Li

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.


2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Yongfeng Wei ◽  
Jinyang Huo ◽  
Zhenjun Wang ◽  
Jiangtao Gao

Emulsified asphalt needs to be cured for a certain age after demulsification to produce strength, which seriously affects the traffic opening time. In this work, microwave heating technology was applied for emulsified asphalt repair materials. Steel slag with high microwave activity was adopted to improve the performance of emulsified asphalt repair materials by microwave heating. Effects of steel slag sizes and contents on the heating rate, temperature distribution, and thermal performance of emulsified asphalt repair materials were analyzed by close microwave heating, open microwave heating, and repair simulation tests. Results show that the temperature of emulsified asphalt repair materials presents three different heating stages under microwave irradiation. The “critical point of phase transition” in the three stages is gradually advanced with the increase in steel slag content. The core temperature and maximum temperature of emulsified asphalt repair materials with different steel slag sizes are basically the same; however, the heat distribution of emulsified asphalt repair materials is significantly different. In contrast to conventional asphalt mixture, there exists a smaller temperature difference. The temperature of repairing materials can reach above 80°C. The interface area can form an embedded interface structure. Incorporation of steel slag and adoption of microwave heating are effective to improve the performance of emulsified asphalt repair materials.


Author(s):  
Jamilla Emi Sudo Lutif Teixeira ◽  
Aecio Guilherme Schumacher ◽  
Patrício Moreira Pires ◽  
Verônica Teixeira Franco Castelo Branco ◽  
Henrique Barbosa Martins

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.


2012 ◽  
Vol 457-458 ◽  
pp. 435-438
Author(s):  
Xue Dong Guo ◽  
Cao Jian ◽  
Xiang Yang Fang

In this paper,study water content and water stability of AC and SMA asphalt mixtures, and reach the following conclusions. In the normal saturated condition, the maximum water content of AC and SMA asphalt mixture is 0.28% and 0.32%.And in the vacuum saturated condition, the maximum water content of AC and SMA asphalt mixture is 0.8% and 0.78%.The water of AC and SMA asphalt mixture separately take 8 days and 9 days to drain completely in the normal saturated condition. But in the vacuum saturated condition, the time is more than two months. In different water content conditions, the splitting tensile strength of AC asphalt mixture is 0%> 100%> 25%> 75%> 50%.But the splitting tensile strength of SMA asphalt mixture is 0%> 100%> 25%> 50%> 75%.


2011 ◽  
Vol 255-260 ◽  
pp. 3432-3436
Author(s):  
Xian Yuan Tang ◽  
Jie Xiao

This paper systematically elaborates the impact upon performance of emulsion asphalt cold reclaimed asphalt mixture by different RAP contents, through a series of testing on six cold reclaimed asphalt mixtures with various RAP contents, such as single axle compression test, 15°C indirect tensile strength (ITS) test, 40°C rutting test and -10°C low-temperature bending beam test. Testing results indicate that 15°C ITS decreases from around 0.75 MPa to 0.58 MPa with the RAP content of mixture increasing from 0% to 100%. 40°C dynamic stabilities reduce considerably from around 19,000 time/mm of 0% RAP mixture to 3,600 time/mm of 100% RAP mixture. -10°C failure strains only change from 1500με to 2000με.


Materials ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 610 ◽  
Author(s):  
Michał Sarnowski ◽  
Karol Kowalski ◽  
Jan Król ◽  
Piotr Radziszewski

In the course of manufacturing, transport and installation, road bitumens and asphalt mixtures can be exposed to the impact of elevated process temperatures exceeding 240 °C. This mainly applies to the mixtures used for road pavements and bridge deck insulation during adverse weather conditions. The heating process should not change the basic and rheological properties of binders and the asphalt mixtures that to a degree cause the degradation of asphalt pavement durability. The work involved analyzing the properties of non-modified bitumens and SBS polymer modified bitumens, heated at temperatures of 200 °C, 250 °C and 300 °C for 1 h. Next, the asphalt mixtures were heated in the same temperatures. Based on the developed Overheating Degradation Index (ODI) it was demonstrated that polymer-modified bitumens were characterized by higher overheating sensitivity A(ODI) than non-modified bitumens, which was confirmed by mixture test results. Overheating limit temperatures T(ODI) were determined, which in the case of polymer-modified bitumens are up to 20 °C lower than for non-modified bitumens. When the temperature increases above T(ODI), loss of viscoelastic properties occurs in the material which causes, among other effects, a loss of resistance to fatigue cracking.


Sign in / Sign up

Export Citation Format

Share Document