Study on guardrail post behavior located on organic soil using simplified experimental and numerical methods

For the purpose of road safety, it is vital to reduce the severity of road accidents and increase safety around the roadway area by deploying guardrails. In case of a car crash, a guardrail post must be deformable so that such restraint is not too abrupt due to the occupant’s sensitivity. Soil type influences on the guardrail post behavior have been a somewhat unfounded variable due to the high soil heterogeneity and challenging interpretation of its real implications on the safety of guardrail systems. Since little attention is concentrated on evaluating the guardrail post behavior through simplified procedures, this article aims to provide a simplified experimental and numerical approach to study the behavior of guardrail posts located on organic soil. Results of laboratory and in-situ tests indicated that guardrail posts behavior located on organic soil depends on section orientation, driving depth, and loading speed. To confirm and compare the in-situ tests, simplified numerical simulations through Plaxis 3D software were carried out, and data from numerical modeling approved the accuracy of in-situ results.The authors acknowledge the financial support by FCT / MCTES through national funds (PIDDAC) under the R&D Unit Institute for Sustainability and Innovation in Structural Engineering (ISISE), under reference UIDB/04029/2020; and ANI through national funds (Portugal 2020), under project “BARROD - Barreiras de Segurança Rodoviária”, reference 33497

Mechanical Behavior of a Mine Tailing Stabilized with a Sustainable Binder

Mining is a primary sector for the national economy of many countries, but exploiting these natural resources causes negative impacts on the environment. Tailings produced during mining, called mine tailings, have to be disposed of, and for that purpose, they are often mixed with Portland cement to control environmental toxicity and improve their mechanical properties. However, the high environmental impacts of producing Portland cement are well known. In this sense, sustainable binders based on the alkaline activation of industrial wastes have been studied as an alternative to using Portland cement. This study focused on applying a sustainable binder based on the alkaline activation of fly ash to improve the mechanical performance of a mine tailing from a mine located in Portugal. Geotechnical tests and chemical analysis were conducted to characterize the mine tailing and fly ash used in the alkaline activation process. In addition, triaxial tests were performed to evaluate the mechanical performance of the specimens, with both natural and stabilized tailings. The developed study proved that stabilized tailing with activated fly ash shows promising mechanical performance showing that this approach can be an excellent alternative to using Portland cement