Concrete is currently the most used construction material, mainly due to its mechanical strength, chemical stability, and low cost. This material is affected by wear processes caused by the environment, which lead to a reduction in the useful life of the infrastructure in the long term. These wear processes can cause cracks, corrosion of reinforcing steel, loss of load capacity, and loss of concrete section, among other problems. Considering the above, it is necessary to carry out durability studies on concrete to determine the integrity conditions in which the infrastructure is found, the reasons for its deterioration, the environmental factors that affect it, and its useful life under these conditions, and develop restoration or protection plans. Generally, the durability studies include non-destructive testing such as ultrasonic pulse velocity, electrical resistivity, porosity measurement, and capillary absorption rate. These techniques make it possible to characterize the concrete and obtain information such as the total volume of pores, susceptibility to corrosion of the reinforcing steel, decrease in mechanical resistance, cracks, presence of humidity, and aggressive ions inside the concrete. In this work, two durability studies are presented with non-destructive tests carried out on active piers that are 20 and 40 years old. These are located in coastal areas in southern Mexico on the Gulf of Mexico side, with 80% average annual relative humidity, temperatures above 33 °C on average, high concentrations of salts, load handling, vibrations, flora and fauna typical of the marine ecosystem, etc. The results obtained reveal important information about the current state of the piers and the damage caused by the environment over time. This information allowed us to make decisions on preventive actions and develop appropriate and specific restoration projects for each pier.

Las nanopartículas de óxidos metálicos se encuentran entre los nanomateriales más utilizados en diversos sectores, como la medicina, la agricultura, la industria alimentaria y los dispositivos electrónicos, debido a sus propiedades funcionales, como gran área superficial, estabilidad química y actividad antimicrobiana. Sin embargo, su creciente producción y uso han incrementado su liberación al medio ambiente, especialmente en ecosistemas acuáticos. Diversos estudios han demostrado que estas NPs pueden inducir efectos tóxicos en organismos acuáticos afectando el equilibrio ecológico. La toxicidad depende de factores como el tipo de óxido metálico, el tamaño de las NPs, la carga superficial y su comportamiento en medios acuosos. En esta revisión se analizan las características fisicoquímicas de las nanopartículas de dióxido de titanio (NPs TiO2), de óxido de zinc (NPs ZnO) y de óxido de cobre (NPs CuO). La revisión resume los mecanismos de acción y la toxicidad asociada con estas NPs con el objetivo de proporcionar una visión general sobre su impacto ecológico y los desafíos actuales en su evaluación y regulación.

Concrete is the most important construction material, and improving its durability properties is a topic in constant development owing to the economic costs that the degradation of concrete implies. Different nanoparticles have been reported to improve concrete durability, although the positive results are not a generality. Among these nanomaterials, graphene oxide stands out as an option for improving concrete properties, such as its compressive strength, which could increase the useful life of concrete infrastructure. This study addresses the effects of graphene oxide on the durability properties of concrete, with the aim of obtaining data on the viability of graphene oxide as an additive in concrete. The incorporation of graphene oxide into concrete was carried out through graphene oxide suspensions that were incorporated into concrete mixtures with a high water/cement ratio. The characterization of concrete was done using non-destructive testing such as ultrasonic pulse velocity, electrical resistivity, porosity, capillary absorption, chloride ion permeability, and other characterization methods such as compressive strength, XPS, SEM, and EDS. Together, these tests provided an overview of the concrete durability properties that are improved, affected, or unchanged by the presence of graphene oxide. In this study, a chemical analysis was also carried out on concrete modified with graphene oxide. The results show that graphene oxide improves the compressive strength of concrete, but the effect on durability properties is negligible; however, there are indications that, in combination with other additives, improvements can be achieved, so it is advisable to continue with these studies.

Concrete is the most used construction material, but its long-term performance depends on durability. Although fly ash has been used as a supplementary cementitious material, the effects of its mechanical activation on the concrete durability require further investigation. This study evaluated the influence of replacing 30% of cement with natural Class F fly ash (NFA) and ground fly ash (GFA) in concrete with a water-to-binder ratio (w/b) of 0.62, using a mixture without fly ash (WFA) as reference. Mechanical activation was performed by milling the fly ash, followed by characterization through particle size analysis and X-ray diffraction. Concrete durability was assessed using electrical resistivity, ultrasonic pulse velocity (UPV), water absorption, porosity, rapid chloride permeability (RCPT), carbonation resistance, and compressive strength tests. Mechanical milling reduced and transformed the ash morphology from spherical to amorphous, while quartz and mullite remained the main crystalline phases. Compared with CNFA, CGFA exhibited up to 101% higher electrical resistivity, 39.6% greater resistance to chloride penetration, 10.8% improved carbonation resistance, 0.4% lower water absorption, and a 5.38% reduction in porosity, although compressive strength decreased by more than 20%. These results demonstrate that mechanically activated fly ash is a viable alternative for enhancing the concrete durability performance exposed to aggressive environments.