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Externally bonded Fiber Reinforced Composite (FRC) materials, such as Fiber Reinforced Polymers (FRP) and Fiber Reinforced Cementitious Matrix (FRCM), have been increasingly used over the last decades for retrofitting existing structural elements due to their excellent mechanical and physical properties. However, the effectiveness of the reinforcement depends on the quality of the adhesion between the reinforcement and its substrate. The present paper reports the results of an experimental campaign in which the Ultrasonic Pulse Velocity (UPV) testing has been applied to detect the presence of adhesion defects at the interface FRC-concrete. UPV has been carried out on concrete specimens strengthened with different types of FRC. Some inclusions have been specifically placed at the interface between the reinforcement and the concrete to simulate adhesion defects. UPV has been applied both in the direct and in the semi-direct mode, to simulate different realistic on-site situations, including the possible inaccessibility of some parts of the element to check. Results show that UPV, applied by means of both direct and semi-direct modes, allows to identify the presence of adhesion defects, and evoke the possibility of discriminating between different defects.
Giovanna Concu; Nicoletta Trulli. Direct and semi-direct ultrasonic testing for quality control of FRC-concrete adhesion. Structures 2021, 32, 54 -64.
AMA StyleGiovanna Concu, Nicoletta Trulli. Direct and semi-direct ultrasonic testing for quality control of FRC-concrete adhesion. Structures. 2021; 32 ():54-64.
Chicago/Turabian StyleGiovanna Concu; Nicoletta Trulli. 2021. "Direct and semi-direct ultrasonic testing for quality control of FRC-concrete adhesion." Structures 32, no. : 54-64.
Timber buildings are experiencing a rapid diffusion due to their good performance and their sustainability; however, some steps of structural timber production process, such as drying, are energy-intensive and environmentally impactful, and many wood species are also affected by low yield. Therefore, it would be important to determine the quality of the green material, that is, in wet condition, before undergoing the most impactful and expensive production steps. This paper describes a research aimed at quantifying the variation of the dynamic modulus of elasticity MoEdyn, which is commonly used for structural timber mechanical grading, from wet to dry condition in Sardinian maritime pine boards to be used for the production of laminated timber, and to examine the relationship between wet and dry MoEdyn. The MoEdyn was determined from measurements of the velocity of sonic waves propagating through the boards. The results show that the dry MoEdyn can be estimated starting from boards sonic testing in the wet condition, so providing a basis for implementing Sardinian maritime pine pre-grading in order to obtain the reduction of manufacturing costs, the abatement of environmental impact, and the increase of structural grade yield.
Giovanna Concu. Prediction of Maritime Pine Boards Modulus of Elasticity by Means of Sonic Testing on Green Timber. Applied Sciences 2021, 11, 1748 .
AMA StyleGiovanna Concu. Prediction of Maritime Pine Boards Modulus of Elasticity by Means of Sonic Testing on Green Timber. Applied Sciences. 2021; 11 (4):1748.
Chicago/Turabian StyleGiovanna Concu. 2021. "Prediction of Maritime Pine Boards Modulus of Elasticity by Means of Sonic Testing on Green Timber." Applied Sciences 11, no. 4: 1748.
This paper illustrates the potential of using wood as a structural material in terms of sustainable construction and analyses the opportunities offered by the plant of production processes based on the use of locally-grown wood to the end of promoting the development of sustainable economies in narrow and interconnected communities like those of the islands. In detail, the convenience of planting in Sardinia a supply chain for manufacturing structural laminated timber elements made of locally-grown maritime pine is addressed, also by referring to the results of a research activity devoted to this purpose.
Giovanna Concu. Sustainability of the Timber Supply Chain on the Island of Sardinia. Transactions on Petri Nets and Other Models of Concurrency XV 2020, 12255, 353 -367.
AMA StyleGiovanna Concu. Sustainability of the Timber Supply Chain on the Island of Sardinia. Transactions on Petri Nets and Other Models of Concurrency XV. 2020; 12255 ():353-367.
Chicago/Turabian StyleGiovanna Concu. 2020. "Sustainability of the Timber Supply Chain on the Island of Sardinia." Transactions on Petri Nets and Other Models of Concurrency XV 12255, no. : 353-367.
The complex characteristics of explosion load as well as its increasingly high frequency in the civil environment highlight the need to develop models representing the behavior of structures under blast load. This work presents a probabilistic study of the performance of framed reinforced concrete buildings designed according to the current Italian NTC18 and European EC8 technical standards. First, a simplified single degree of freedom model representing the structural system under blast load has been developed. Then, a probabilistic approach based on Monte Carlo simulation analysis highlighted the influence of seismic demand on the behavior of Reinforced Concrete RC buildings subjected to blast load.
Flavio Stochino; Alessandro Attoli; Giovanna Concu. Fragility Curves for RC Structure under Blast Load Considering the Influence of Seismic Demand. Applied Sciences 2020, 10, 445 .
AMA StyleFlavio Stochino, Alessandro Attoli, Giovanna Concu. Fragility Curves for RC Structure under Blast Load Considering the Influence of Seismic Demand. Applied Sciences. 2020; 10 (2):445.
Chicago/Turabian StyleFlavio Stochino; Alessandro Attoli; Giovanna Concu. 2020. "Fragility Curves for RC Structure under Blast Load Considering the Influence of Seismic Demand." Applied Sciences 10, no. 2: 445.
Open access peer-reviewed chapter
Giovanna Concu. Introductory Chapter: Timber and Sustainability in Construction. Timber Buildings and Sustainability 2019, 1 .
AMA StyleGiovanna Concu. Introductory Chapter: Timber and Sustainability in Construction. Timber Buildings and Sustainability. 2019; ():1.
Chicago/Turabian StyleGiovanna Concu. 2019. "Introductory Chapter: Timber and Sustainability in Construction." Timber Buildings and Sustainability , no. : 1.
Currently, the construction industry consumes annually an average of 40% of resources, producing about 40% of solid waste and pollution. In this context it becomes imperative for the building sector to move towards a sustainable dimension. This need for sustainability is further amplified in territories such as the islands, which are often particularly vulnerable to climate changes and over-dependent on fossil fuels and energy imports. Therefore, it is essential that the islands are able to manage their resources in a sustainable way, in order to become increasingly efficient, self-sufficient and be able to protect their environmental heritage. In this context, the prospect of a circular economy is the best path to sustainable development in the construction sector. The present paper aims to illustrate two lines of research implemented on the island of Sardinia (Italy) with the aim of analyzing the sustainability of the production and use of local building materials in the island construction sector. In particular, the research lines study the chain of load-bearing energy-efficient timber panels and that of recycled aggregates for concrete buildings.
Giovanna Concu; Luisa Pani. Buildings Materials, Sustainability and Circular Economy. Research Projects in the Island of Sardinia. INCREaSE 2019 2019, 935 -949.
AMA StyleGiovanna Concu, Luisa Pani. Buildings Materials, Sustainability and Circular Economy. Research Projects in the Island of Sardinia. INCREaSE 2019. 2019; ():935-949.
Chicago/Turabian StyleGiovanna Concu; Luisa Pani. 2019. "Buildings Materials, Sustainability and Circular Economy. Research Projects in the Island of Sardinia." INCREaSE 2019 , no. : 935-949.
The paper illustrates the results of an experimental test which intends to check the efficacy of ultrasonic testing (UT) in detecting anomalies inside concrete elements. For this purpose, UT has been carried out on a small concrete wall having different defects deliberately settled inside the wall during casting. A grid of several measurements points has been arranged on the wall surfaces and for each point the ultrasonic signal has been acquired after passing through the thickness of the wall and the propagation velocity V has been extracted and analyzed. A graphic representation of V distribution has been implemented by a map where each pixel identifies one measurement point and is representative of its neighborhood. This map highlights areas with different velocity values, and allows to visually detect areas having particularly low velocity. The matching between the low-velocity areas and the artificial defects has been analyzed, and the level of accuracy of the V map in detecting and sizing the concrete inner defects has been discussed with reference to different spacing of the grid points. Finally, some considerations regarding the choice of the most suitable measurements grid have been addressed.
Giovanna Concu; Nicoletta Trulli. Concrete Defects Sizing by Means of Ultrasonic Velocity Maps. Buildings 2018, 8, 176 .
AMA StyleGiovanna Concu, Nicoletta Trulli. Concrete Defects Sizing by Means of Ultrasonic Velocity Maps. Buildings. 2018; 8 (12):176.
Chicago/Turabian StyleGiovanna Concu; Nicoletta Trulli. 2018. "Concrete Defects Sizing by Means of Ultrasonic Velocity Maps." Buildings 8, no. 12: 176.
In Italy, timber- and wood-based products are being increasingly used in construction due to their outstanding physical and mechanical properties. This paper presents the preliminary results of an experimental programme that aims to explore the possible use of Sardinian timber as structural material. For this purpose, locally grown maritime pine boards were visually graded and tested to destruction. Their physical (density, knots, grain deviation, annual ring width, moisture content, etc.) and mechanical (modulus of elasticity, tensile strength, ultrasonic velocity) properties were measured and are reported in this paper. Four-point bending tests were also carried out on cross-laminated timber panels made of the previously graded wood. The results demonstrate that it is possible to use maritime pine grown in Sardinia to produce cross-laminated timber panels for use in construction.
Giovanna Concu; Barbara De Nicolo; Massimo Fragiacomo; Nicoletta Trulli; Monica Valdes. Grading of maritime pine from Sardinia (Italy) for use in cross-laminated timber. Proceedings of the Institution of Civil Engineers - Construction Materials 2018, 171, 11 -21.
AMA StyleGiovanna Concu, Barbara De Nicolo, Massimo Fragiacomo, Nicoletta Trulli, Monica Valdes. Grading of maritime pine from Sardinia (Italy) for use in cross-laminated timber. Proceedings of the Institution of Civil Engineers - Construction Materials. 2018; 171 (1):11-21.
Chicago/Turabian StyleGiovanna Concu; Barbara De Nicolo; Massimo Fragiacomo; Nicoletta Trulli; Monica Valdes. 2018. "Grading of maritime pine from Sardinia (Italy) for use in cross-laminated timber." Proceedings of the Institution of Civil Engineers - Construction Materials 171, no. 1: 11-21.
Cross Laminated Timber (CLT) panels are used as building construction materials due to their excellent properties. In particular, with this construction technique it is possible to produce high quality structural members by assembling normal/low quality planks. Timber boards should be graded according to the current regulations before their use as structural components. Among grading methodologies, non-destructive Sonic Testing can be applied. Sonic Testing is a non destructive technique widely used for building material quality control. In this paper, the reliability of Sonic Testing in giving information on some mechanical characteristics of Cross Laminated Timber panels is discussed also in relation to wood type, layers number and layers configuration of the panels. For this purpose, both Sonic Testing and destructive bending tests have been carried out on several CLT panels manufactured by using boards of Spruce and Sardinian Maritime Pine. Regression analysis between sonic and mechanical parameters (static modulus of elasticity and bending strength) has been performed and is critically discussed in the paper
G. Concu; B. De Nicolo; R. Riu; N. Trulli; M. Valdes; Massimo Fragiacomo. Sonic testing on cross laminated timber panels. Insights and Innovations in Structural Engineering, Mechanics and Computation 2016, 1727 -1730.
AMA StyleG. Concu, B. De Nicolo, R. Riu, N. Trulli, M. Valdes, Massimo Fragiacomo. Sonic testing on cross laminated timber panels. Insights and Innovations in Structural Engineering, Mechanics and Computation. 2016; ():1727-1730.
Chicago/Turabian StyleG. Concu; B. De Nicolo; R. Riu; N. Trulli; M. Valdes; Massimo Fragiacomo. 2016. "Sonic testing on cross laminated timber panels." Insights and Innovations in Structural Engineering, Mechanics and Computation , no. : 1727-1730.
G Concu; B De Nicolo; N Trulli; M Valdes. Concrete compressive strength estimation by means of combined NDT. Emerging Technologies in Non-Destructive Testing VI 2015, 335 -339.
AMA StyleG Concu, B De Nicolo, N Trulli, M Valdes. Concrete compressive strength estimation by means of combined NDT. Emerging Technologies in Non-Destructive Testing VI. 2015; ():335-339.
Chicago/Turabian StyleG Concu; B De Nicolo; N Trulli; M Valdes. 2015. "Concrete compressive strength estimation by means of combined NDT." Emerging Technologies in Non-Destructive Testing VI , no. : 335-339.
The aim of this study was to evaluate ultrasonic P-wave velocity as a feature for predicting some physical and mechanical properties that describe the behavior of local building limestone. To this end, both ultrasonic testing and compressive tests were carried out on several limestone specimens and statistical correlation between ultrasonic velocity and density, compressive strength, and modulus of elasticity was studied. The effectiveness of ultrasonic velocity was evaluated by regression, with the aim of observing the coefficient of determination r 2 between ultrasonic velocity and the aforementioned parameters, and the mathematical expressions of the correlations were found and discussed. The strong relations that were established between ultrasonic velocity and limestone properties indicate that these parameters can be reasonably estimated by means of this nondestructive parameter. This may be of great value in a preliminary phase of the diagnosis and inspection of stone masonry conditions, especially when the possibility of sampling material cores is reduced.
Giovanna Concu; Barbara De Nicolo; Mónica Valdés. Prediction of Building Limestone Physical and Mechanical Properties by Means of Ultrasonic P-Wave Velocity. The Scientific World Journal 2014, 2014, 1 -8.
AMA StyleGiovanna Concu, Barbara De Nicolo, Mónica Valdés. Prediction of Building Limestone Physical and Mechanical Properties by Means of Ultrasonic P-Wave Velocity. The Scientific World Journal. 2014; 2014 (3):1-8.
Chicago/Turabian StyleGiovanna Concu; Barbara De Nicolo; Mónica Valdés. 2014. "Prediction of Building Limestone Physical and Mechanical Properties by Means of Ultrasonic P-Wave Velocity." The Scientific World Journal 2014, no. 3: 1-8.
G. Concu; B. De Nicolo; C. Piga; V. Popescu. Non-Destructive Testing of Stone Masonry using Acoustic Attenuation Tomography Imaging. Proceedings of the Twelfth International Conference on Civil, Structural and Environmental Engineering Computing 2009, 1 .
AMA StyleG. Concu, B. De Nicolo, C. Piga, V. Popescu. Non-Destructive Testing of Stone Masonry using Acoustic Attenuation Tomography Imaging. Proceedings of the Twelfth International Conference on Civil, Structural and Environmental Engineering Computing. 2009; ():1.
Chicago/Turabian StyleG. Concu; B. De Nicolo; C. Piga; V. Popescu. 2009. "Non-Destructive Testing of Stone Masonry using Acoustic Attenuation Tomography Imaging." Proceedings of the Twelfth International Conference on Civil, Structural and Environmental Engineering Computing , no. : 1.
G. Concu; B. De Nicolo. Non-destructive methods as a tool in the assessment of monumental buildings condition. Structural Studies, Repairs and Maintenance of Heritage Architecture XI 2009, 109, 349 -358.
AMA StyleG. Concu, B. De Nicolo. Non-destructive methods as a tool in the assessment of monumental buildings condition. Structural Studies, Repairs and Maintenance of Heritage Architecture XI. 2009; 109 ():349-358.
Chicago/Turabian StyleG. Concu; B. De Nicolo. 2009. "Non-destructive methods as a tool in the assessment of monumental buildings condition." Structural Studies, Repairs and Maintenance of Heritage Architecture XI 109, no. : 349-358.
B De Nicolo; L Pani; G Concu; Fausto Mistretta. Experimental evaluation of indirect sonic wave transmission technique in the diagnosis and monitoring of concrete slabs. Concrete Repair 2008, 213 -214.
AMA StyleB De Nicolo, L Pani, G Concu, Fausto Mistretta. Experimental evaluation of indirect sonic wave transmission technique in the diagnosis and monitoring of concrete slabs. Concrete Repair. 2008; ():213-214.
Chicago/Turabian StyleB De Nicolo; L Pani; G Concu; Fausto Mistretta. 2008. "Experimental evaluation of indirect sonic wave transmission technique in the diagnosis and monitoring of concrete slabs." Concrete Repair , no. : 213-214.