A hyper-heuristic algorithm for VRP problem and its application in highway construction

Influence of curing conditions on engineering properties of controlled low strength material made with cementless binder

This study synthesizes the information on the use of waste materials in highway construction. The information was obtained from a review of published literature supplemented by: recent unpublished reports, presentations of research updates by professionals at different forums, anti personal meetings with the experts. In addition, a questionnaire regarding the use of waste materials was prepared and distributed to each of the state highway agencies. A majority of states responded to the questionnaire, giving a summary of current practices in the use of waste materials in highway construction and their experiences on the technical, environmental, and economic aspects of the various applications of the materials. The report briefly gives the state-of-the-practice in the use of the waste materials in highway construction in the United States and discusses the applications of selected waste materials, including: waste tires, waste glass, reclaimed paving materials, slags and ashes, building rubble, sewage sludge, and incinerator residue. An evaluation based on the technical, environmental, and economic factors indicated that reclaimed paving materials, coal fly ash, blast furnace slag, bottom ash, boiler slag. Steel slag and rubber tires have significant potential to replace conventional materials for various applications in highway construction, and should be projected for future construction. Specific applications of the waste products and the potential problems associated with their usage in highway operations, which must be addressed prior to their extensive use, are included in the report .

The concept of acceptance sampling plans ensures the quality of products and materials used in highway construction. These acceptance sampling plans require the testing of each and every individual lot of products for the highway construction and materials. This approach of sampling is applicable and appropriate if the supplier or contractor is unreliable. If the contractor is consistent and reliable, then instead of inspecting each and every lot of products, skip-lot sampling system can be utilized where only a fraction of the lots are inspected after assuring the quality and after a certain number of conforming lots is obtained. Skip-lot sampling plan can be used for reducing the amount of inspection on product that has an excellent quality history. Thus, skip-lot sampling plans are designed to reduce inspection costs. Moreover, skip-lot concept is sound and useful and it is economically advantageous in the design of sampling plans. Hence, this paper presents an improved system of skip-lot sampling plans designated as SkSP-V plan for the application of highway construction and materials. Advantages of this plan over the existing skip-lot plan and AASHTO’s lot-by-lot sampling plan are also discussed. The efficiency of this new plan is also investigated.

Applying basic oxygen furnace (BOF) slag as aggregate in asphalt mixture is continuously investigated due to the increasing shortage of natural aggregate in recent years. However, the negative effect of BOF’s expansion in water greatly limits its further application in pavement construction. To address this problem, this paper studied the volume stability of BOF, and its asphalt mixture relied on actual engineering. The asphalt mixtures contained BOF aggregate was designed by the Marshall method with three different gradation types (AC‐16, AC‐20, and ATB‐25). Besides, both laboratory samples and the core samples from field drilling were investigated in volume expansion rate after curing in a water bath. The economic and resource benefits of BOF replacement of natural aggregates were also analyzed. The results showed that the free calcium oxide content of BOF slag is positively related to the particle sizes. Nevertheless, the expansion rates of both the BOF aggregate and its asphalt mixture were less than 1%, which meant the BOF aggregate applied to the asphalt mixture meets the practical engineering requirements. The maximum allowable free calcium oxide content for large‐grain size of steel slag is the smallest; it is also recommended that the expansibility of large‐grain steel slag should be the first concern in the application. The resource assessment indicated that the use of steel slag for the construction of a trial section of one kilometer of single lane can save 967 tons of natural aggregates. The economic evaluation showed that the use of steel slag instead of natural aggregates for surface course construction could reduce the investment by 16.87%. The experimental methods and conclusions mentioned in this article provide stable references to enhance the development of sustainable pavement by recycling metallurgical slag in highway construction.

Leaching characterization of dry flue gas desulfurization materials produced from different flue gas sources in China

This paper takes Zihui expressway as an example, from the perspective of green design and construction of mountain expressway, this paper mainly discusses and analyzes the project characteristics and technical requirements of Zihui expressway, and puts forward the key technology of green design and construction based on the establishment of green highway.

This paper presents a robust control algorithm for exponentially stable tracking control of a differentially steered Wheeled Mobile Robot (WMR). The exponential tracking property is guaranteed with kinematic uncertainties, such as wheel slippage and radius errors. The control algorithm has been designed for use in a WMR which is being specifically developed for applications in highway maintenance and construction. For such applications, the uncertainties arise due to the road surface conditions and the high loads encountered (both inertial and tool forces). However, the system under development is equipped with a two dimensional cable extension transducer which has been proven to be a rugged and accurate position measurement system (Hong, et al., 1995), so that the robust control algorithm developed is suitable and ensures good tracking performance. The algorithm is applicable to any differentially steered WMRs provided that accurate position measurement is available. The efficiency of the robust control algorithm is illustrated with numerical simulations.

Shale is the most abundant sedimentary rock worldwide and is often used as a construction material in many civil engineering applications. However, this material is easily deteriorated when it is exposed to cyclic wetting and drying processes. Deterioration of shale used for highway construction applications may lead to bearing capacity failure of highway embankments and instability of the adjacent slopes. The susceptibility of shale to deterioration is typically quantified by durability. In this context, durability is a measure of the rate and magnitude of deterioration and is used to describe the susceptibility of a material to environmental factors such as mechanical and chemical weathering. The Jar Slake test is a visual observation-based immersion test used to qualitatively assess the durability of shale. Although the test is relatively rapid and easy to perform, the results are very subjective. This paper presents a new method that utilizes the immersion aspect of the Jar Slake test, which simulates water-induced deterioration of shale. However, the proposed method eliminates the subjectivity associated with the Jar Slake test. The proposed method quantifies the durability of shale using time dependent changes in electrical conductivity measurements of a shale-water solution. In this method, there is only need to monitor the electrical conductivity of the shale-water solution for up to 60 min and predict the durability of the shale by a simple model developed from this study. The results of the proposed method were found to compare well with other more rigorous methods to assess durability.