Moisture sensitivity and mechanical performance assessment of warm mix asphalt containing by-product steel slag

The major goal of sustainable practices is to preserve raw resources through the utilization of waste materials as an alternative to natural resources. Decreasing the temperature required to produce asphalt mixes contributes to environmental sustainability by reducing energy consumption and toxic emissions. In this study, warm mix asphalt incorporating coarse steel slag aggregates was investigated. Warm mix asphalt was produced at different temperatures lower than the control asphalt mixes (hot mix asphalt) by 10, 20, and 30 °C. The performances of the control and warm mix asphalt were assessed through laboratory tests examining stiffness modulus, dynamic creep, and moisture sensitivity. Furthermore, a response surface methodology (RSM) was conducted by means of DESIGN EXPERT 11 to develop prediction models for the performance of warm mix asphalt. The findings of this study illustrate that producing warm mix asphalt at a temperature 10 °C lower than that of hot mix asphalt exhibited the best results, compared to the other mixes. Additionally, the warm mix asphalt produced at 30 °C lower than the hot mix asphalt exhibited comparable performance to the hot mix asphalt. However, as the production temperature increases, the performance of the warm mix asphalt improves.

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Moisture Sensitivity of Crumb Rubber Modified Modifier Warm Mix Asphalt Additive for Two Different Compaction Temperatures

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/140/1/012072 ◽

2018 ◽

Vol 140 ◽

pp. 012072 ◽

Cited By ~ 1

Author(s):

Munder A Bilema ◽

Mohamad Y Aman ◽

Norhidayah A Hassan ◽

Kabiru A Ahmad ◽

Hamza M Elghatas ◽

...

Keyword(s):

Crumb Rubber ◽

Warm Mix Asphalt ◽

Moisture Sensitivity

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ON-LINE PERFORMANCE ASSESSMENT AND FAULT DIAGNOSIS OF MECHANICAL SYSTEMS

Transactions of the Canadian Society for Mechanical Engineering ◽

10.1139/tcsme-2015-0056 ◽

2015 ◽

Vol 39 (3) ◽

pp. 705-715 ◽

Cited By ~ 1

Author(s):

Shang-Liang Chen ◽

Yin-Ting Cheng ◽

Hsien-Cheng Liu ◽

Yun-Yao Chen

Keyword(s):

Fault Diagnosis ◽

Performance Assessment ◽

Mechanical System ◽

High Speed ◽

Mechanical Performance ◽

Wavelet Packet ◽

Principal Component ◽

Spindle Motor ◽

Diagnostic Model ◽

On Line

This study integrates sensors, signal capture equipment, industrial computers and machinery health check-up software to develop an On-line Performance Assessment and Fault Diagnosis of Mechanical System, helping engineers predict mechanical conditions. Physical quantities captured by the sensors is utilized to process physical signals, and the Wavelet Packet Energy method is used for the feature extraction of non-stationary signals in coordination with the Principal Component Analysis for feature selection. This study establishes On-line Performance Assessment and Fault Diagnosis of Mechanical System based on Discriminant Analysis which is able to immediately determine the mechanical performance. When abnormal mechanical conditions occur, Bayesian Network will be activated to construct error diagnostic model and determine possible causes of error or malfunction of the machinery. Finally, the system is applied to the fan motor, high-speed spindle motor and AC motor of the machine tool. Experimental results show that the theory can effectively diagnose mechanical performance remarkable with an accuracy rate of 92.50% or higher.

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Evaluating the Surface Free Energy and Moisture Sensitivity of Warm Mix Asphalt Binders Using Dynamic Contact Angle

Advances in Civil Engineering ◽

10.1155/2019/9153603 ◽

2019 ◽

Vol 2019 ◽

pp. 1-15 ◽

Cited By ~ 6

Author(s):

Muhammad Rafiq Kakar ◽

Meor Othman Hamzah ◽

Mohammad Nishat Akhtar ◽

Junita Mohamad Saleh

Keyword(s):

Contact Angle ◽

Free Energy ◽

Hot Mix Asphalt ◽

Asphalt Binder ◽

Moisture Damage ◽

Warm Mix Asphalt ◽

Work Of Adhesion ◽

Moisture Sensitivity ◽

Modified Binders ◽

Production Temperature

From the environmental conservation perspective, warm mix asphalt is more preferable compared to hot mix asphalt. This is because warm mix asphalt can be produced and paved in the temperature range 20–40°C lower than its equivalent hot mix asphalt. In terms of cost-effectiveness, warm mix asphalt can significantly improve the mixture workability at a lower temperature and thus reduce greenhouse gas emissions, to be environment friendly. However, the concern, which is challenging to warm mix asphalt, is its susceptibility to moisture damage due to its reduced production temperature. This may cause adhesive failure, which could eventually result in stripping of the asphalt binder from the aggregates. This research highlights the significance of Cecabase warm mix additive to lower the production temperature of warm mix asphalt and improvise the asphalt binder adhesion properties with aggregate. The binders used in the preparation of the test specimen were PG-64 and PG-76. The contact angle values were measured by using the dynamic Wilhelmy plate device. The surface free energy of Cecabase-modified binders was then computed by developing a dedicated algorithm using the C++ program. The analytical measurements such as the spreadability coefficient, work of adhesion, and compatibility ratio were used to analyze the results. The results inferred that the Cecabase improved the spreadability of the asphalt binder over limestone compared to the granite aggregate substrate. Nevertheless, the Cecabase-modified binders improved the work of adhesion. In terms of moisture sensitivity, it is also evident from the compatibility ratio indicator that, unlike granite aggregates, the limestone aggregates were less susceptible to moisture damage.

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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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Ladle Steel Slag in Activated Systems for Construction Use

Minerals ◽

10.3390/min10080687 ◽

2020 ◽

Vol 10 (8) ◽

pp. 687

Author(s):

Diego Aponte ◽

Oriol Soto Martín ◽

Susana Valls del Barrio ◽

Marilda Barra Bizinotto

Keyword(s):

Mechanical Performance ◽

Steel Slag ◽

Value Added ◽

Physical And Mechanical Properties ◽

Linear Shrinkage ◽

Alkali Activation ◽

Optimal Dosage ◽

Refining Steel ◽

Different Temperatures ◽

Industry Needs

The construction industry needs to reduce greenhouse gases, in which cement production is currently responsible for generating between 4% and 6% of the total CO2 released into the atmosphere. Similarly, many industries produce large amounts of solid waste, which often have low value-added applications or are directly taken to landfills, with consequent negative environmental impacts. One of these industries is the steel industry, which in 2016 generated 18.4 Mt of slag (melting and refining slag) among all European Union countries. In terms of refining steel slag (ladle or white slag), it is estimated that for each ton of steel, between 20 and 30 kg of slag is produced; that is, in 2016, more than 700,000 tons of white slag were generated. It is also known that this material has cementitious properties and can be used as a precursor in alkaline activation processes. Depending on the concentrations used of the activating agent, a higher or lower mechanical performance of the developed materials can be obtained. This work studied the alkali activation of a ladle slag used to manufacture mortars, subjecting them to an initial curing of 24 h at different temperatures (20, 40, and 70 °C). Sodium silicate and sodium hydroxide were used as activating agents, using percentages of Na2O between 5% and 10% to obtain an optimal dosage of the activator. The physical and mechanical properties of the mortars were evaluated at different ages of curing. In addition, monitoring was undertaken of linear shrinkage due to drying and the mineralogical changes due to activation and curing time.

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