Influence of the crushing process of recycled aggregates on concrete properties

This work intends to evaluate the (mechanical and durability) performance of concrete made with coarse recycled concrete aggregates (CRCA) obtained using two crushing processes: primary crushing (PC) and primary plus secondary crushing (PSC). This analysis intends to select the most efficient production process of recycled aggregates (RA). The RA used here resulted from precast products (P), with strength classes of 20 MPa, 45 MPa and 65 MPa, and from laboratory-made concrete (L) with the same compressive strengths. The evaluation of concrete was made with the following tests: compressive strength; splitting tensile strength; modulus of elasticity; carbona-tion resistance; chloride penetration resistance; capillary water absorption; and water absorption by immersion. These findings contribute to a solid and innovative basis that allows the precasting industry to use without restrictions the waste it generates. © (2015) Trans Tech Publications, Switzerland.

Robustness of corroded reinforced concrete structures. A structural performance approach

Structure and Infrastructure Engineering, 1-17

A reliability-based measure of robustness for concrete structures subjected to corrosion

This work is a contribution to the definition and assessment of structural robustness. Special emphasis is given to reliability of reinforced concrete structures under corrosion of longitudinal reinforcement. On this communication several authors’ proposals in order to define and measure structural robustness are analyzed and discussed. The probabilistic based robustness index is defined, considering the reliability index decreasing for all possible damage levels. Damage is considered as the corrosion level of the longitudinal reinforcement in terms of rebar weight loss. Damage produces changes in both cross sectional area of rebar and bond strength. The proposed methodology is illustrated by means of an application example. In order to consider the impact of reinforcement corrosion on failure probability growth, an advanced methodology based on the strong discontinuities approach and an isotropic continuum damage model for concrete is adopted. The methodology consist on a two-step analysis: on the first step an analysis of the cross section is performed in order to capture phenomena such as expansion of the reinforcement due to the corrosion products accumulation and damage and cracking in the reinforcement surrounding concrete; on the second step a 2D deteriorated structural model is built with the results obtained on the first step of the analysis. The referred methodology combined with a Monte Carlo simulation is then used to compute the failure probability and the reliability index of the structure for different corrosion levels. Finally, structural robustness is assessed using the proposed probabilistic index.

Lime-metakaolin mortars for historical buildings repair: study of the hardening reaction

International Conference Durable Structures: from construction to rehabilitation. Lisbon, LNEC, 31 May-1 June 2012

Lime based mortars for ceramic tile application: the influence of the lime, the use of a metakaolin and the curing

Intern.Conference AZULEJAR, Univ. Aveiro, 10-12 October 2012

Lean production in the precast concrete components’ industry

Proceedings IGLC-19, July 2011, Lima, Perú

Influence of lime type and curing conditions on lime and lime-metakaolin mortars

Durability of Building Materials and Components (Vasco Peixoto de de Freitas, J.M.P.Q. Delgado, eds.), Building Pathology and Rehabilitation, vol. 3, VIII, 105-126. ISBN: 978-3-642-37474-6 (Print) 978-3-642-37475-3 (Online). Springer-Verlag Berlin Heidelberg. DOI: 10.1007/978-3-642-37475-3_5

Chromatic reintegration of historical mortars with lime-based pozzolanic consolidant products

3rd Historic Mortars Conference, 11-14 September 2013, Glasgow, Scotland

Influence of curing conditions in lime-metakaolin blended mortars – A mineralogical and mechanical study

3rd Historic Mortars Conference, 11-14 September 2013, Glasgow, Scotland

Physical and chemical assessment of lime–metakaolin mortars: Influence of binder:aggregate ratio

Cement & Concrete Composites 45 (2014) 264–271

Mechanical and mineralogical properties of natural hydraulic lime-metakaolin mortars in different curing conditions

Construction and Building Materials 51 (2014) 287–294

Cement-cork mortars for thermal bridges correction. Comparison with cement-EPS mortars performance

Construction and Building Materials 49 (2013), 315-327

Evaluation of Pozzolanic Reactivity of Artificial Pozzolans

Materials Science Forum Vols. 730-732 (2013) pp 433-438

Robustness of corroded reinforced concrete structures

Dissertação para obtenção do Grau de Doutor em Engenharia Civil

Precast concrete wall-foundation connection. Development of a seismic dissipative connection

Seismic events are a major factor to consider in structural design of buildings in many countries. With the purpose of saving lives, most of the design codes lead to structural solutions that withstand large seismic actions without collapsing, but without taking into account a possible usage of the structures after the earthquake. As a result, it is necessary to consider the time needed to repair/retrofit the damaged structures (i.e. the downtime) since this period of inactivity may result in huge financial implications for the occupants of the buildings. In order to minimise the damages and simplify repair operations, structural solutions with rocking systems and negligible residual displacements have been developed during the last two decades. Systems with precast concrete rocking walls were studied with the aim of investigat- ing suitable and convenient structural alternatives to minimise the damage in case of an earthquake. Experimental, numerical and analytical analyses on post-tensioned solutions, with and without energy dissipation devices, were carried out in this research. The energy dissipation devices were made from steel angles that were further developed during the research. Different solutions for these devices were experimentally tested under cyclic loading and the results are presented. Numerical and analytical work on steel angles was also carried out. Regarding the concrete rocking wall systems, two concrete rocking wall systems were studied: post-tensioned walls and post-tensioned walls with energy dissipation devices. In the latter, the solution was to fix them externally to the wall, allowing their easy replacement after an earthquake. It is shown that the dissipaters are a viable solution for use in precast concrete rocking wall systems. A building case study is presented. The comparison between a traditional monolithic system and a hybrid solution was carried out, allowing the evaluation of the efficiency of the solution that was developed.