Absorption, Porosity, Capillarity and Chloride Diffusion in Ultra High Performance Concretes

Concrete durability performance can be assessed by a number of parameters, among which permeability properties are key. In this experimental work, the permeability to water and the diffusion of chlorides in Ultra High Performance Concrete (UHPC) are studied. To this end, three types of concrete were made: two Ultra High Performance (one with fibers and one without fibers) and a Conventional Concrete (CC) of w/c ratio equal to 0.5. The compressive strength of Ultra High Performance Concretes was 130 MPa, and that of conventional concrete was 50 MPa. All of them were cured at a temperature of 20°C and RH greater than 95% until the age of 28 days. In the case of UHPCs with fibers, some of the specimens were not placed in the curing chamber but were allowed to air dry in a laboratory environment in order to study the influence of curing on this type of concrete. The results show that UHPCs have remarkably lower water permeability than CC, with the water absorption and water porosity being in the order of 8 times lower, the water absorption by capillarity being in the order of 30 times lower, and the non-steady-state chloride migration coefficient more than 100 times inferior. The values recorded of absorption and capillarity in UHPCs with and without fibers were very similar. However, the permeability to chlorides was somewhat higher in concretes with steel fibres. With regard to the influence of curing, in air-dried UHPCs there was a significant increase in permeability to both water and chlorides. Despite this, the chloride migration coefficient registered remained very close to the values proposed by some recommendations for very high durability concrete

Integrated Sensor Network for Monitoring Steel Corrosion in Concrete Structures

The developed Integrated Sensor Network (ISN) allows a non-destructive monitoring of the rebar condition at different parts of the structure. The corrosion sensor allows the accurate determination of the corrosion rate (µm/year). Moreover, additional sensors are integrated in order to detect relevant changes in the concrete electrochemical condition. The ISN has been published as an international invention patent (reference number WO 2016/177929 A1). The system is based on an economic, simple, reliable and durable technology, which makes its implementation viable on new and repaired reinforced concrete structures (RCS). Therefore, it is also possible monitoring non-accessible parts such as deep foundations or submerged and buried zones. In any case, no technical personnel are needed because the acquisition, storage and transmission of data is autonomous. In this way, it is possible a remote corrosion assessment of several RCS. In addition, the system needs minimum maintenance works and shows low failure rates. The ISN has been installed for corrosion monitoring of a marine prestressed structure built with Formex®, an Ultra High Performance Fibre Reinforced Concrete (UHPFRC). Five zones of the structure are being monitored. After seven months of monitoring, the corrosion rate (CRATE) stands around 0.2 µm/year, lower than the corrosion rate of the conventional concrete specimens installed (0.5 µm/year). In any case, CRATE is under 1.16 µm/year, the threshold above which the corrosion begins to be considered significant

Comparative Study of Infliximab Versus Adalimumab in Refractory Uveitis due to Behçet's Disease: National Multicenter Study of 177 Cases.

To compare the efficacy of infliximab (IFX) versus adalimumab (ADA) as a first-line biologic drug over 1 year of treatment in a large series of patients with refractory uveitis due to Behçet's disease (BD). We conducted an open-label multicenter study of IFX versus ADA for BD-related uveitis refractory to conventional nonbiologic treatment. IFX or ADA was chosen as the first-line biologic agent based on physician and patient agreement. Patients received 3-5 mg/kg intravenous IFX at 0, 2, and 6 weeks and every 4-8 weeks thereafter, or 40 mg subcutaneous ADA every other week without a loading dose. Ocular parameters were compared between the 2 groups. The study included 177 patients (316 affected eyes), of whom 103 received IFX and 74 received ADA. There were no significant baseline differences between treatment groups in main demographic features, previous therapy, or ocular sign severity. After 1 year of therapy, we observed an improvement in all ocular parameters in both groups. However, patients receiving ADA had significantly better outcomes in some parameters, including improvement in anterior chamber inflammation (92.31% versus 78.18% for IFX; P = 0.06), improvement in vitritis (93.33% versus 78.95% for IFX; P = 0.04), and best-corrected visual acuity (mean ± SD 0.81 ± 0.26 versus 0.67 ± 0.34 for IFX; P = 0.001). A nonsignificant difference was seen for macular thickness (mean ± SD 250.62 ± 36.85 for ADA versus 264.89 ± 59.74 for IFX; P = 0.15), and improvement in retinal vasculitis was similar between the 2 groups (95% for ADA versus 97% for IFX; P = 0.28). The drug retention rate was higher in the ADA group (95.24% versus 84.95% for IFX; P = 0.042). Although both IFX and ADA are efficacious in refractory BD-related uveitis, ADA appears to be associated with better outcomes than IFX after 1 year of follow-up