Shear tests on thermal insulating clay unit masonry walls with thin layer mortar

Mauerwerk ◽  
2018 ◽  
Vol 22 (6) ◽  
pp. 385-398 ◽  
Author(s):  
Detleff Schermer ◽  
Jonathan Schmalz ◽  
Udo Joachim Meyer ◽  
Matija Gams ◽  
Marjana Lutman ◽  
...  
Keyword(s):  
Thin Layer ◽  
Masonry Walls ◽  
Shear Tests ◽  
Thermal Insulating

scholarly journals Energy and seismic drawbacks of masonry: a unified retrofitting solution

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
F. Longo ◽  
A. Cascardi ◽  
P. Lassandro ◽  
M. A. Aiello
Keyword(s):  
Thermal Resistance ◽  
Mechanical Performance ◽  
Point Of View ◽  
Experimental Program ◽  
Masonry Walls ◽  
Shear Tests ◽  
Plane Shear ◽  
Innovative Solutions ◽  
Inorganic Matrix ◽  
Comfort Criteria

AbstractAll over the world, a large part of existing buildings is not adequate to satisfy the safety requirement and the thermal comfort criteria. For this reason, the interest in structural and energy retrofitting systems has steadily grown in the last decades. In this scenario, an innovative thermal resistant geopolymer mortar has been developed and used for Inorganic Matrix Composite (IMC) systems aimed to a combined seismic and energy new retrofitting technique. The geopolymer-based IMC is able to ensure competitive mechanical properties with respect to the traditional lime-based IMCs and, at the same time, a significant reduction in thermal conductivity. In this paper, an experimental program is reported considering small-scaled masonry panels with double-side IMC-retrofitting and determining both the in-plane shear strength and the thermal resistance. The experimental shear tests are aimed to compare the mechanical performance of the geopolymer innovative systems with those of the traditional lime-based ones. Moreover, the thermal resistance gain of the innovative solutions was measured and compared with traditional systems. The results evidenced the effectiveness of the proposed technique that significantly improved the performances of masonry walls from both the thermal and the mechanical point of view.

scholarly journals Experimental Characterization of Traditional Mortars and Polyurethane Foams in Masonry Wall

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Dora Foti ◽  
Michela Lerna ◽  
Vitantonio Vacca
Keyword(s):  
Applied Load ◽  
Thermal Inertia ◽  
Masonry Wall ◽  
Polyurethane Foams ◽  
Masonry Walls ◽  
Masonry Buildings ◽  
Experimental Characterization ◽  
Shear Tests ◽  
The Poor

Masonry is a composite material largely used in construction. It exhibits several advantages, including significant compressive strength, thermal inertia, and aesthetic beauty. A disadvantage of masonry is mainly related to the inadequate shear strength due to the poor capacity and ductility of the adopted mortar. This aspect is crucial in seismic areas. In this paper, the behavior of polyurethane foams, used as adhesives for the construction of thin joints brick masonry walls, has been investigated. First, the characterization of components was carried out, followed by laboratory uniaxial tests on masonry walls and shear tests on triplets. Moreover, a comparison of the behavior of the foam-brick walls with respect to the traditional mortars masonry was carried out, as the type of joints varies and the arrangement of the holes of the bricks varies with respect to the direction of the applied load. Results provide indications on which adhesive has to be adopted for masonry buildings in reference to the site of construction (i.e., seismic hazard).

Experimental Study on Masonry Panels Strengthened by GFRP: The Role of Inclination between Mortar Joints and GFRP Sheets

2014 ◽  
Vol 624 ◽  
pp. 559-566 ◽  
Author(s):  
Claudio Mazzotti ◽  
Barbara Ferracuti ◽  
Alessandro Bellini
Keyword(s):  
Failure Modes ◽  
Vertical Axis ◽  
Image Correlation ◽  
Masonry Walls ◽  
Shear Tests ◽  
Shear Strengthening ◽  
Lap Shear ◽  
Dic Technique ◽  
Frp Sheet

For the shear strengthening of masonry walls, different configurations for FRP sheets are currently used in real application, such as vertical, horizontal or diagonal strips. In the last configuration the FRP sheet is inclined with respect to the direction of mortar joints. In the experimental campaign presented in this paper, it is investigated whether the FRP-masonry bond could be affected by this inclination. In order to analyze this issue, three different typologies of masonry panels (with different textures) retrofitted by FRP sheets, inclined of 45 degrees with respect to the vertical axis of the specimen, are subjected to single-lap shear tests. Results of shear tests are presented in terms of maximum debonding forces, force-elongation curves, failure modes and strain profiles along the specimens. The use of Digital Image Correlation (DIC) technique allowed to obtain complete strain maps on the surface of the specimens tested, with the purpose of investigating possible variations in the strain field within the bonded area.

Half-Scale Tests on Masonry Panels Strengthened with Pultruded FRP Frames

2019 ◽  
Vol 817 ◽  
pp. 95-102
Author(s):  
Francesca Sciarretta ◽  
Salvatore Russo
Keyword(s):  
Shear Strength ◽  
Epoxy Adhesive ◽  
Analytical Models ◽  
Masonry Walls ◽  
Bolted Joint ◽  
Shear Tests ◽  
Plane Shear ◽  
Lime Mortar ◽  
Clay Bricks ◽  
Connection System

The research explores the capabilities of frames of pultruded FRP profiles as seismic strengthening for masonry walls. A programme is currently in progress at the IUAV University of Venice, consisting of in-plane shear tests on half-scale panels. The selected masonry type is traditional, i.e. clay bricks and lime mortar joints. The goal is to assess the effectiveness of the strengthening system with respect to the undamaged condition of masonry. A particular focus is on the connection system between the panel and the frame, i.e. epoxy adhesive connection and bolted joint. The results will be implemented in FEM analyses and analytical models to predict the system's and the joints' shear strength.

Applications of Photoelectron Microscopy

1976 ◽  
Vol 34 ◽  
pp. 506-507
Author(s):  
William J. Baxter
Keyword(s):  
Electron Microscopy ◽  
Thermal Decomposition ◽  
Chemical Composition ◽  
Ultraviolet Radiation ◽  
Thin Layer ◽  
Edge Effects ◽  
Electron Optics ◽  
Surface Layers ◽  
Crystalline Orientation ◽  
Fluorescent Screen

In this form of electron microscopy, photoelectrons emitted from a metal by ultraviolet radiation are accelerated and imaged onto a fluorescent screen by conventional electron optics. image contrast is determined by spatial variations in the intensity of the photoemission. The dominant source of contrast is due to changes in the photoelectric work function, between surfaces of different crystalline orientation, or different chemical composition. Topographical variations produce a relatively weak contrast due to shadowing and edge effects.Since the photoelectrons originate from the surface layers (e.g. ∼5-10 nm for metals), photoelectron microscopy is surface sensitive. Thus to see the microstructure of a metal the thin layer (∼3 nm) of surface oxide must be removed, either by ion bombardment or by thermal decomposition in the vacuum of the microscope.

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