Search results for "Mortar"
showing 10 items of 99 documents
Nonlinear FE analysis of out-of-plane behaviour of masonry walls with and without CFRP reinforcement
2014
Abstract The out-of-plane behaviour of unreinforced and CFRP reinforced masonry wall is studied by means of experimental investigation and numerical FE modelling. The latter is based on a linear constitutive law both for ashlars and mortar joints constituting masonry and the lines of potential delamination are taken into account by means of an interface element with bi-linear law, reproducing the opening failure mode. When reinforcement is introduced, an interface element with bi-linear law is also used, reproducing sliding failure mode. Comparison between numerical and experimental results show the reliability of the modelling. Moreover, a parametric analysis is carried out in order to inv…
Risk of failure for the salso river railroad steel bridge
2020
Abstract The degradation state of railroad steel bridges is one of the most important and difficult aspects to be interpreted. The use of steel bridges started from 1900, and they are still in service today as railroad bridges. The case study examined was that of a bridge railroad steel bridge having a total length of 112 m and constituted by three isostatic, reticular beams having a Pratt type composition. The substructures (two shoulders and two intermediate piles) are in masonry with a reinforced concrete beam in the upper portion. The structure (steel bridge and piers) is in a degraded state. To determine the degradation level, non-destructive and partially destructive tests were carrie…
A study of spalling behaviour of PAN fibre-reinforced concrete by thermal analysis
1993
Comparisons are made between polypropylene (PP) fibres and polyacrylonitrile (PAN) fibres in order to relate the thermal properties of fibres with the respective fibre mortar behaviour under thermal exposure. Thermogravimetry (TG), differential scanning calorimetry (DSC) and thermochromatography (ThGC) are utilized. When a cementitious fibre mortar is being heated, several physical phenomena occur in the temperature range between 100°C and 200°C. There is a significant difference in the thermal behaviour between PP and PAN fibres. PP fibres melt at 160–170°C. The non‐melting behaviour of PAN fibre together with its rapid exothermic degradation reactions at around 300°C may add risk to the s…
Quasi-brittle porous material: Simulated effect of stochastic air void structure on compressive strength
2021
Abstract The effect of porosity comprised of spherical air voids on the compressive strength of quasi-brittle material was studied via simulations. The simulated porous structures were based on pore size distributions of two mortar samples measured by X-ray microtomography. While the simulation method set practical limits on the size of sample, the base of the statistics was established by simulating 128 small structures generated by sampling from pore structures of two mortars. By studying the application of the classical strength-porosity formulas to the simulated data, a new simple model was formed. A linear relationship was achieved between the cubic root of air void fraction (porosity)…
Characterization of mortars from ancient and traditional water supply systems in Sicily
2008
Long aged mortars from ancient hydraulic constructions of Sicily, i.e. the Roman aqueduct of Thermae and the Punic cisterns and traditional water supply systems in Pantelleria, have been characterised by means of XRD analysis, optical microscopy and simultaneous thermal analysis to correlate the hydraulic properties to the texture and to their different role in the construction, i.e. lining, covering, roofing and joint mortars. According to a procedure proposed in the literature all of the samples, but two air hardening ones, show high hydraulicity, which somehow can be related to the characteristics of aggregates.
Finte Pietre. Architettura dell'apparire e conservazione dei valori culturali
2012
Il volume presenta gli esiti di una ricerca incentrata sulla conoscenza delle finiture architettoniche di pietra artificiale, con particolare attenzione agli intonaci brevettati nel 1901 dai fratelli Li Vigni. Le attività di studio sono condotte attraverso la ricognizione dei documenti conservati presso l’Archivio Centrale dello Stato a Roma, e compiono una rigorosa selezione e analisi dei brevetti con l’obiettivo di tracciare il percorso evolutivo dei metodi d’intonacatura ed evidenziare i legami che s’instaurano tra le ricerche in corso nei diversi paesi. Nel XIX secolo i ricercatori di molte nazionalità avviano una selezione critica delle ricette tramandate dal passato e perfezionano pro…
Study and evaluation of nano-structured cellulose fibers as additive for restoration of historical mortars and plasters
2017
Abstract UPM bio-fibrils are nano-structured cellulose fibers (nano-fibrils) produced by UPM Kymmene-Corporation, a Finnish company. This paper reports a preliminary study about nano-fibrils to determine their possible use for restoration of historical mortars and plasters. The aim of this study is to investigate the behavior of some mixtures added with nano-fibrils in their properties for conservative purposes. These mixtures reproduce the composition of historical mortars and plasters, made of natural hydraulic lime (NHL 3.5) and river sand. After 28 days of hardening, the properties of specimens with nano-fibrils were compared with untreated one to understand how nano-fibrils interact wi…
Production technology of early-hellenistic lime-based mortars originating from a punic-Roman residential area in palermo (sicily)
2016
The topic of this study is the mineralogical and petrographic characterization of lime-based mortars of Hellenistic-Roman age (3rd century BCE), collected from a residential area located in the present historical centre of Palermo, near the remains of the Punic-Roman walls. The collected mortars have been analyzed by optical microscopy, X-ray powder diffraction analysis and scanning electron microscopy, coupled with energy-dispersive spectrometry. The aim of the study was the characterization of the mortars as pertaining to their aggregate and binder composition, aggregate size distribution and aggregate/binder ratio, so as to establish the provenance of raw materials and acquire informatio…
Advances in experimental characterization and modelling of FRCM composites for structural retrofitting
2023
Questa tesi presenta i risultati di una campagna sperimentale incentrata sulla caratterizzazione della trazione dei basalt e glass FRCM e della caratterizzazione del legame di aderenza composito-Calcarenite. Il lavoro sperimentale è completato dalla proposta di due modelli numerici sia per prove di trazione che per quelle di aderenza. L'indagine sperimentale è stata condotta considerando l'influenza di diversi rinforzi, matrici e metodi di prova. I risultati sperimentali consentono di valutare l'effetto della malta sulle curve sforzo-deformazione, la resistenza, la duttilità e le modalità di crisi. Inoltre, la tesi fornisce un importante contributo per valutare l'influenza di diversi metodi…
USE OF FOAMED END-OF-WASTE PLASTIC AGGREGATES AS INTERNAL CURING WATER RESERVOIR INTO A CEMENTITIOUS MORTAR
2017
Shrinkage phenomena represent an important issue for cementitious materials. There are several procedures able to reduce shrinkage phenomena, in particular, external and internal curing. The latter consider the possibility to add water reservoir that are able to release water during the curing period. In this study, porous plastic aggregates were used as internal curing water reservoir.