The use of concrete in civil infrastructure is highly demanded in structural and nonstructural elements. However, the high production of concrete could lead to severe pollution in the world. This pollution can be decreased using sustainable materials mixed with cement to obtain sustainable concrete. These sustainable materials include reinforcing fibers (e.g., steel, polypropylene, carbon fibers), recycled materials (e.g., tire rubber, crushed glass, plastic, industrial waste) as well as organic and inorganic elements as concrete aggregates and reinforcement elements. The sustainable construction materials can reduce the amount constitutive elements of concrete required for civil constructions. In addition, some sustainable materials added to cement could improve some properties of the concrete, like the compressive and flexural strength of concrete structural elements. Thus, the maintenance requirements or early replacement of these structural elements could be decreased. This review presents recent investigations about the performance of different sustainable concrete types. In addition, we include the effects on the mechanical properties of the concrete caused by the incorporation of several sustainable materials. In addition, recommendations for the use and testing of sustainable concrete are reported. These materials have potential applications in the sustainable concrete infrastructure in future smart cities.

Footbridges are structures that may experience vibration amplification problems caused by pedestrian and/or wind actions. Design codes deal with these phenomena limiting the natural frequencies and the maximum accelerations expected. Aiming at taking into consideration these dynamic phenomena, current procedures to evaluate the structural performance of light-weight bridges based on experimental dynamic analysis are evaluated in this study. To achieve this, the dynamic response of three pedestrians walking, running and jumping was obtained. Maximum comfort limits of dynamic responses were then determined. The results indicate that codes could overestimate the level of vibration in this kind of footbridge

Constructed wetlands (CWs) are highly effective in wastewater treatment and have generated lines of research with a focus on technological development and implemented innovations. This work concentrates on the most recent technical and scientific advances that have obtained optimal results in the construction of CWs using sustainable materials and the use of ornamental plants and other aquatic plants. Efficiency is also documented through models and simulation with neural networks, the use of the random forest method, and the use of software such as MODFLOW, MODPATH, and COMSOL Multiphysics. The information shown is structured by geographical area and addresses regions of Africa, Asia, Europe, North America, South America, and Oceania. It is important to consider that the optimization and innovation of CW for pollutant removal may benefit developing countries that do not have sufficient infrastructure to meet the demand for municipal and industrial wastewater.

Prior research has demonstrated that incorporating solid waste from various sources, such as plastics, civil engineering waste, and industrial and mining waste, into pavement and civil works mixes has notable environmental benefits. This includes reducing the over-exploitation of aggregate banks and preventing waste materials from being deposited in open-pit landfills for extended periods. This review focuses on sustainable aggregates produced from solid waste with rheological or mechanical properties suitable for replacing conventional aggregates in asphalt or hydraulic concrete mixtures. The aim is to determine the optimal replacement percentage in the mixture to directly impact pavement performance. This review also delves into the impact on fatigue resistance and permanent deformation based on the type of waste material used in construction. Additionally, using sustainable aggregates presents added benefits for pavement binders, such as inhibiting reflection cracks, reducing traffic noise, and prolonging the service life of the pavement. However, it is crucial to study the percentage of replacement of sustainable aggregates in conjunction with other materials using mathematical models and simulations to ensure a substantial contribution to the sustainability of the construction industry.

Resonators based on micro and nanoelectromechanical systems (MEMS/NEMS) are used in many applications, including biological and gas sensors, magnetic field sensors, RF switches, accelerometers, piezoelectric micro and nanogenerators, and viscosity sensors. The design of these resonators requires analytical models to predict their mechanical behavior and optimize the sensitivity and resolution. However, most of these models are only applied to resonators with rectangular and uniform cross-sections. In this paper, we present the analytical modeling to determine the first bending resonant frequency, out-of-plane deflections, and normal stresses of MEMS/NEMS-based multilayered resonators with variable cross-sections and multiple fixed supports. The proposed modeling is derived using the well-known Rayleigh and Macaulay methods, as well as the Euler-Bernoulli beam theory. This analytical modeling is applied to four multilayered resonators with different clamped supports and non-uniform cross-sections. The results of our analytical modeling agree well with respect to those of finite element method (FEM) models and experimental data reported in the literature. The proposed analytical modeling can be used to estimate the frequency shift of resonators due to variations of their geometric parameters, number of clamped-supports or mechanical properties of the materials. Furthermore, this modeling can be used to obtain optimal designs of resonators that ensure safe operations and enhanced performance for sensors and energy harvesters in telecommunications, automotive sector, aerospace industry, consumer electronics, non-destructive testing, and navigation.