scholarly journals Assessing the influence of self-healing capacity of lime-based mortars on brick-mortar interface strength in masonry units

2018 ◽  
Vol 199 ◽  
pp. 02015
Author(s):  
Cristina De Nardi ◽  
Antonella Cecchi ◽  
Liberato Ferrara
Keyword(s):  
Shear Strength ◽  
Fe Model ◽  
Self Healing ◽  
Structural Elements ◽  
Shear Tests ◽  
Interface Shear ◽  
Clay Bricks ◽  
Heritage Buildings ◽  
Restoration Work ◽  
Materials Used

Among the materials used in constructions, self-healing ones have been widely studied, including polymers, asphalts, cement binders; nonetheless the issue of the implementations and engineering of the self-healing capacity of lime-based mortars has been seldom investigated. As a matter of fact, the aforementioned capacity in restoration of building heritage, as well as in concrete structures, would provide an interesting contribution in terms of durability of the same restoration work as well as of the building as a whole. The aim of this research is to study the influence of healing capacity on the masonry behaviour by means of shear tests. The choice to perform shear tests, with or without lateral precompression is due to the representativeness of conditions truly occurring in masonry structural elements when in service. “Triplet specimens” have been fabricated, consisting of 3 clay bricks and 2 layers of purposed-design mortar, to mimic the compositions of mortars which can be actually found in existing heritage buildings. The methodology envisages three phases: a first series of specimens, after 28 days curing in lab environment, was tested to evaluate the shear strength. Then, on a second series of samples, a damage was induced by loading them to a prescribed fraction (70%) of the shear strength, determined as above in the previous stage; samples were subsequently immersed in water for 3 months and re-tested at the end of this curing period. Results clearly show that the autogenous healing capacity is responsible of an interesting recovery of the interface shear strength. The reliability of this approach has been also investigated by comparing the experimental results with a simplified FE model.

scholarly journals Hygric Properties of Machine-Made, Historic Clay Bricks from North-Eastern Poland (Former East Prussia): Characterization and Specification for Replacement Materials

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6706
Author(s):  
Maria Tunkiewicz ◽  
Joanna Misiewicz ◽  
Pawel Sikora ◽  
Sang-Yeop Chung
Keyword(s):  
Historic Buildings ◽  
Micro Computed Tomography ◽  
Existing Building ◽  
Clay Bricks ◽  
North Eastern ◽  
Heritage Buildings ◽  
Experimental Laboratory ◽  
Materials Used ◽  
East Prussia

This paper deals with the hygric characterization of early 20th century machine-made clay bricks, representative of great number of historical buildings in north-eastern Poland. Heritage buildings have a high potential for adaptive reuse, which is strictly connected with an urge for knowledge about the properties of these existing building envelopes. To better understand the hygric behavior of historic buildings, various experimental laboratory tests, including density, water absorption, compressive strength and freeze-thaw resistance, were conducted. In order to assess the microstructural characteristics of the tested bricks, mercury intrusion porosimetry (MIP) and X-ray micro-computed tomography (micro-CT) tests were performed. These tests were conducted on clay bricks from historic buildings, as well as on those that are currently being produced, in order to identify the relationship between the materials used in the past and the replacements produced presently. This paper addresses the lack of systematic application of existing standards for evaluating the state of the conservation of historic bricks and for establishing the specifications for replacement bricks. The results of conducted study and further research will be the basis for creating a historic materials database. It would be a useful tool for selecting bricks that correspond with the historically used materials and help to maintain homogenous structure of the restored buildings.

Study on Combining Performance of Young and Old Concrete with Mechanical Joint Element

2008 ◽  
Vol 400-402 ◽  
pp. 537-542 ◽  
Author(s):  
Xiao Yan Zhao ◽  
Wen Ling Tian ◽  
Xin Liang Jiang ◽  
Xiao Wei Wang ◽  
Ming Jie Zhou
Keyword(s):  
Shear Strength ◽  
Shear Test ◽  
Shear Tests ◽  
Working Mechanism ◽  
Mechanical Joint ◽  
Splitting Strength ◽  
Strength Tests ◽  
Split Test ◽  
Joint Element ◽  
Materials Used

The new way of using mechanical joint element (MJE) to cross the interface of new and old concrete to reinforce the combination is put forward. The splitting strength tests of young and old concrete were carried out to investigate the effects on splitting strength of MJE and different materials used to embed the MJE. The working mechanism of the MJE in split test is discussed emphatically. The shear tests of young and old concrete were carried out too. The effects on shear strength of MJE and interface agent are discussed. The mechanism of MJE in shear test is analyzed synchronously.

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.

Measurement of unsaturated soil – geomembrane interface shear-strength parameters

2007 ◽  
Vol 44 (1) ◽  
pp. 78-88 ◽  
Author(s):  
J S Sharma ◽  
I R Fleming ◽  
M B Jogi
Keyword(s):  
Shear Strength ◽  
Normal Stress ◽  
Pore Pressure ◽  
Unsaturated Soil ◽  
Pressure Transducer ◽  
Shear Behaviour ◽  
Direct Shear ◽  
Shear Tests ◽  
Interface Shear Strength ◽  
Interface Shear

Laboratory tests of soil–geomembrane interface shear strength are typically carried out with no provision for the measurement of pore pressures at the soil–geomembrane interface. This paper describes a series of soil–geomembrane interface shear tests carried out with continuous measurement of suction close to the interface during the shearing process. The tests were conducted using a modified direct shear box with a miniature pore-pressure transducer installed adjacent to the surface of the geomembrane. Results of the interface shear tests conducted using this method show that it is quite effective in evaluating shear behaviour at the interface between a geomembrane and an unsaturated soil at low matric suction values. The results suggest that soil suction contributes to shearing resistance at low normal stress values. At higher normal stress values, the interface shear behaviour appears to be governed only by the magnitude of total normal stress.Key words: geomembrane, interface shear strength, suction, direct shear test, pore-pressure transducer.

Punch-shear tests and size effects for evaluating the shear strength of machinable ceramics

2004 ◽  
Vol 95 (5) ◽  
pp. 372-376 ◽  
Author(s):  
Yiwang Bao ◽  
Haibin Zhang ◽  
Yanchun Zhou
Keyword(s):  
Shear Strength ◽  
Size Effects ◽  
Shear Tests

scholarly journals Sand- and Clay-Photocured-Geomembrane Interface Shear Characteristics Using Direct Shear Test

2021 ◽  
Vol 13 (15) ◽  
pp. 8201
Author(s):  
Lihua Li ◽  
Han Yan ◽  
Henglin Xiao ◽  
Wentao Li ◽  
Zhangshuai Geng
Keyword(s):  
Soil Surface ◽  
Friction Angle ◽  
Direct Shear ◽  
Tensile Crack ◽  
Shear Tests ◽  
Interface Shear ◽  
Direct Shear Tests ◽  
Carbon Black Powder ◽  
Shear Characteristics ◽  
Impermeable Layer

It is well known that geomembranes frequently and easily fail at the seams, which has been a ubiquitous problem in various applications. To avoid the failure of geomembrane at the seams, photocuring was carried out with 1~5% photoinitiator and 2% carbon black powder. This geomembrane can be sprayed and cured on the soil surface. The obtained geomembrane was then used as a barrier, separator, or reinforcement. In this study, the direct shear tests were carried out with the aim to investigate the interfacial characteristics of photocured geomembrane–clay/sand. The results show that a 2% photoinitiator has a significant effect on the impermeable layer for the photocured geomembrane–clay interface. As for the photocured geomembrane–sand interface, it is reasonable to choose a geomembrane made from a 4% photoinitiator at the boundary of the drainage layer and the impermeable layer in the landfill. In the cover system, it is reasonable to choose a 5% photoinitiator geomembrane. Moreover, as for the interface between the photocurable geomembrane and clay/sand, the friction coefficient increases initially and decreases afterward with the increase of normal stress. Furthermore, the friction angle of the interface between photocurable geomembrane and sand is larger than that of the photocurable geomembrane–clay interface. In other words, the interface between photocurable geomembrane and sand has better shear and tensile crack resistance.

Influence of revision arthroplasty on bone/cement interface shear strength

1987 ◽  
Vol 20 (8) ◽  
pp. 824
Author(s):  
J.E. Bechtold ◽  
Y. Dohmae ◽  
R.E. Sherman ◽  
R.B. Gustilo
Keyword(s):  
Shear Strength ◽  
Bone Cement ◽  
Revision Arthroplasty ◽  
Interface Shear Strength ◽  
Interface Shear ◽  
Cement Interface

scholarly journals Skewness and Kurtosis: Important Parameters in the Characterization of Dental Implant Surface Roughness—A Computer Simulation

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Karl Niklas Hansson ◽  
Stig Hansson
Keyword(s):  
Surface Roughness ◽  
Shear Strength ◽  
Roughness Parameter ◽  
Interface Shear Strength ◽  
Interface Shear ◽  
Implant Surface ◽  
Bone Response ◽  
Dental Implant Surface ◽  
Skewness And Kurtosis

The surface roughness affects the bone response to dental implants. A primary aim of the roughness is to increase the bone-implant interface shear strength. Surface roughness is generally characterized by means of surface roughness parameters. It was demonstrated that the normally used parameters cannot discriminate between surfaces expected to give a high interface shear strength from surfaces expected to give a low interface shear strength. It was further demonstrated that the skewness parameter can do this discrimination. A problem with this parameter is that it is sensitive to isolated peaks and valleys. Another roughness parameter which on theoretical grounds can be supposed to give valuable information on the quality of a rough surface is kurtosis. This parameter is also sensitive to isolated peaks and valleys. An implant surface was assumed to have a fairly well-defined and homogenous “semiperiodic” surface roughness upon which isolated peaks were superimposed. In a computerized simulation, it was demonstrated that by using small sampling lengths during measurement, it should be possible to get accurate values of the skewness and kurtosis parameters.

Sign in / Sign up

Export Citation Format

Share Document