Invited Speaker
Dr. Enrico Zacchei
Itecons – Institute for Research and Technological Development in Construction, Energy, Environment and Sustainability, PortugalSpeech Title: Multifactorial and Multiphases Models for Chloride Ingress in RC Structures under Unsaturated Conditions
Abstract: The attack of chloride ions is one of the most important factors affecting the durability of reinforced concrete (RC) structures. The ingress of chloride ions into concrete is usually studied by assuming constant diffusivity and constant surface chloride concentration. However, these two approximations could estimate in an unsatisfactory way the chloride concentration in structures thus the lifetime assessment. Several factors influence the chloride concentration and ingress mechanisms in the convection area. In this presentation, a new time-dependent multifactorial and multiphase model that accounts some effects on chloride surface concentrations in the convection zone is proposed. Several values have been collected to identify the position and the chloride concentration in the section between the diffusion and convection zones. Diffusivity, which is the key parameter of the mechanical diffusion, accounts the water/cement ratio, chloride binding, temperature, concrete age, humidity, concrete deformation, and damage. The surface chloride model considers environment humidity, temperature, irregularities of the concrete surface, and convection area of concrete. Advanced numerical solutions have been carried out to consider space and time dependencies in the model. Results show that the error function-based solutions could underestimate the chloride concentration C for periods < 10 years and for concrete depths > 4.0 cm.
Keywords: Chloride diffusion, superficial chloride, non-constant diffusivity, convection area, concrete irregularities.
Biography: Dr. Enrico Zacchei got his PhD from University of Salamanca, Spain, in co-tutorship with University of São Paulo (USP), Brazil, in Structures. 2º PhD from University State of São Paulo (UNESP) in Structures. Master/bachelor’s degree in Civil Engineering from University of Roma Tre, Italy. He held 13 grants/scholarships, 3 of which for stays at USP (2.5 years), UNESP (8 months), University of Malaga, Spain (9 months). He is the Special Issue Editor of Infrastructures journal. Reviewer for ISI journals. Technical committee member for congresses. 12 years of technical/scientific experience in international companies/institutes. 16 technical projects (14 large projects) and 7 research projects (5 more than 500k euro). Coordinator of 3 projects. More than 15 papers published in high impact journals (ISI/Scopus). More than 30 participations/presentations at congresses. Currently he is a Senior Engineer and PI at ITECONS, Portugal. Research interests: numerical solutions, design of RC and steel structures, earthquake engineering, dynamic analyses.