scholarly journals Effect of Type of Curing and Metakaolin Replacement on Air Lime Mortars for the Durability of Masonries

2021 ◽  
Vol 6 (10) ◽  
pp. 143
Author(s):  
João Monteiro ◽  
Vitor Silva ◽  
Paulina Faria
Keyword(s):  
Relative Humidity ◽  
Atlantic Ocean ◽  
Mechanical Performance ◽  
Early Stage ◽  
Mechanical Parameters ◽  
Curing Conditions ◽  
Physical Chemical ◽  
Lime Mortars ◽  
Hardened Properties

The interest in restoration and maintenance of old masonries towards their durability is nowadays combined with the concept of sustainability and the need to implement more suitable materials for building heritage interventions. This has led to the importance of having a better knowledge of air lime mortars, namely on the effect of pozzolanic additions, curing conditions and evolution at early stages. This study consisted in the characterization of mortars based on hydrated air lime and sand, with 1:2 (lime:sand) volumetric composition, with different weight percentages of substitution of lime by metakaolin (Mk): 0%, 10% and 20%. Mortar prisms were analyzed in three different curing environments: maritime (by the Atlantic Ocean), in laboratory humidity (95 ± 5% relative humidity, RH) and standard (65 ± 5% RH) conditioning. Tests were conducted to evaluate fresh and hardened properties of mortars, considering physical, chemical and mechanical performance at 28, 90 and 180 days. Results showed the viability of applying air lime-Mk mortars with curing conditions similar to the tested ones. In the standard curing, the mortar with 20% Mk revealed advantages in mechanical parameters. Concerning the behaviour towards water, improvements were shown at an early stage with the humid curing, while maritime curing benefited its behaviour for at least up to 6 months.

THE MECHANICAL PERFORMANCE OF TRADITIONAL ADOBE MASONRY COMPONENTS: AN EXPERIMENTAL-ANALYTICAL CHARACTERIZATION OF SOIL BRICKS AND MUD MORTAR

2018 ◽  
Vol 13 (3) ◽  
pp. 17-44 ◽  
Author(s):  
Tiziano Li Piani ◽  
Dennis Krabbenborg ◽  
Jaap Weerheijm ◽  
Lambertus Koene ◽  
Lambertus J. Sluijs
Keyword(s):  
Moisture Content ◽  
Mechanical Characterization ◽  
Mechanical Performance ◽  
Peak Stress ◽  
Organic Content ◽  
Mechanical Parameters ◽  
Multivariate Statistical ◽  
Modern Material ◽  
Curing Conditions

Adobe is an ancient building technology made of sun dried bricks joined together by mud mortar. This paper deals with the physical and mechanical characterization of three different typologies of adobe bricks and one typology of mud mortar produced in Europe. They differed in terms of internal soil element proportions and amount of organic content. Physical tests consisted of granulometry, moisture content and density tests. The mechanical characterization consisted of uniaxial compressive tests and three point bending tests. Tests were performed according to modern material standards. The main mechanical properties both in tension and compression were determined at different curing conditions. The outcome provided in this study offers a general overview on the assessment of the mechanical performance of adobe in relation to the properties and interactions of its soil constituents. In fact, the comparison between components with the same soil mineralogical family and production process made it possible to assess both at a qualitative and quantitative level the effect of the physical properties of the mixture (such as fiber and clay percentages or moisture content) on the mechanical parameters of the resulting bricks and mortar. This paper proposes new predictive formulations of the most relevant material parameters in strength and deformation, such as compressive strength, deformation at peak stress and ultimate displacement for both adobe bricks and mortar. They quantify the influence that water content, clay percentage and fiber reinforcement produce on the mechanical performance of the tested adobe components. This was made possible by means of multivariate statistical analyses on the mechanical parameters derived from all the tested samples.

Performance of Lime-Metakaolin Pastes and Mortars in Two Curing Conditions Containing Kaolin Wastes

2015 ◽  
Vol 668 ◽  
pp. 419-432 ◽  
Author(s):  
Aline Figueirêdo Nóbrega de Azerêdo ◽  
Givanildo Azeredo ◽  
Arnaldo Manoel Pereira Carneiro
Keyword(s):  
Hydrated Lime ◽  
Microstructural Characteristics ◽  
Curing Conditions ◽  
Pozzolanic Material ◽  
Cement Mortars ◽  
Lime Mortars ◽  
Moist Environment ◽  
Hardened State ◽  
Hydrated Products ◽  
Hardened Properties

Many works have shown that metakaolin is very good pozzolanic material for using in lime mortars and Portland cement mortars. Alternatively, many studies also have shown that kaolin wastes, after some treatment, can become a high quality pozzolans. Most of these studies have discussed about the microstructural characteristics and hardened properties of pastes, mortars or concretes mixes containing metakaolin or kaolin wastes cured in moist environment. In this work pastes and mortars made of metakaolin and hydrated lime (L-MK), which the metakaolin was obtained from the kaolin production waste, were assessed in their hardened state. Two curing conditions were considered: dry and moist environment; and three ages of curing (28, 90 and 180 days) were studied. Pastes were assessed by XRD and TG/DTG. In pastes according to the XRD and TG/DTG results, the main hydrated products found were strätlingite, in moist curing, and monocarboaluminate, in dry curing. Properties like flexural and compressive strengths, water absorbed capillarity and loss mass variation were studied in mortars. The results showed that mortars in dry curing presented lower strengths than one in moist curing. In moist curing mortars presented compressive strength values around 12 MPa and in dry curing this value reached 6 MPa. This fact indicate that the strätlingite maybe is responsible for the high strengths in mortars in moist curing when compares with the strengths of mortars cured in dry environment. Further the results showed that mortars in dry curing presented higher water absorbed and mass loss variation than mortars in moist curing.

scholarly journals CHARACTERIZATION OF LIGHTWEIGHT LIME MORTARS CONTAINING BRICK WASTE POWDER

2019 ◽  
Vol 22 ◽  
pp. 133-138
Author(s):  
Martin Vyšvařil ◽  
Tomáš Žižlavský ◽  
Patrik Bayer ◽  
Pavla Rovnaníková
Keyword(s):  
Mechanical Properties ◽  
Quartz Sand ◽  
Pozzolanic Reaction ◽  
Expanded Perlite ◽  
Pore System ◽  
Lime Mortars ◽  
Hardened Properties ◽  
Good Contact ◽  
Powder Content

This work deals with the effects of an expanded perlite (EP) on the hardened properties of air lime mortars with a 50% brick waste powder content. The influence of different substitution of quartz sand by EP is also monitored here. A relationship between EP content and physical-mechanical properties of mortar (flexural and compressive strength, pore system) and mortar frost resistance has been found. Very good contact between the binder matrix and EP surface was observed in microstructural images of mortars that conclusively exhibits the formation of products by pozzolanic reaction on the surface of EP. This work could be helpful for the establishment of the essential proportions of EP and quartz sand to be used in air lime mortars designed for restoration works.

Mineralogical investigations on pozzolanic dolomitic lime mortars to assess the phase development at different curing conditions

2020 ◽  
Author(s):  
Martin Schidlowski ◽  
Tobias Bader ◽  
Anja Diekamp
Keyword(s):  
Relative Humidity ◽  
Simultaneous Thermal Analysis ◽  
Raw Material ◽  
Binder Phase ◽  
Dolomitic Lime ◽  
Curing Conditions ◽  
Phase Development ◽  
Lime Mortars ◽  
Long Time ◽  
Dolomite Rock

<p>For a long time, historical mortars were primarily associated with mortars based on calcium carbonate as the main binder phase. Recent publications show that considerable amounts of magnesium are often present in the binder of historical mortars, which is referred to the use of dolomite rock as raw material (Diekamp, ​​2009; Diekamp, ​​2014). A special feature are Roman and medieval dolomitic lime mortars with the addition of brick fragments as a pozzolanic component (Schidlowski, 2019).In order to characterize the phase formation in modern pozzolanic dolomitic lime mortars, mortar prisms based on dolomitic lime were produced with three different pozzolans (antique and modern brick dust and metakaolin). To draw comparisons with other binders, identical prisms based on calcite and magnesite were produced. These specimens were stored under different environmental conditions (60 % and 95 % relative humidity) and examined by X-ray diffraction and simultaneous thermal analysis after periods of 28, 90 and 180 days.</p><p>The results obtained so far show that the binder phases that have evolved in the mortars based on dolomitic lime are calcite, aragonite, portlandite, brucite and AFm phases. Aragonite is only found in traces in the samples with metakaolin. In contrast to the samples stored at 65 % relative humidity, the samples stored at 95 % relative humidity have lower calcite and higher contents of portlandite and AFm phases.</p><p>No significant differences in the amount of calcite and water-containing mineral phases (portlandite, brucite, hydrotalcite) can be found after 28, 90 and 180 days. It can be concluded that a large part of the reactions has already taken place after 28 days.</p><p>The present study is believed to be beneficial for a thorough understanding of the phase formations in dolomitic lime based mortars at different curing conditions.</p>

Characterization of Bronze Corrosion Products on Exposition to Sulphur Dioxide

2010 ◽  
Vol 138 ◽  
pp. 21-28 ◽  
Author(s):  
B. De Filippo ◽  
L. Campanella ◽  
A. Brotzu ◽  
S. Natali ◽  
D. Ferro
Keyword(s):  
Sulfur Dioxide ◽  
Relative Humidity ◽  
Early Stage ◽  
Xrd Analysis ◽  
Corrosion Products ◽  
X Ray Diffraction ◽  
X Ray ◽  
Weight Variation ◽  
Room Condition

In the main frame of the research aimed to model the corrosion growth on bronze surface, the objective of the work here reported has been to characterize the corrosion products formed on laboratory samples of bronze alloy (Cu Sn12), during the early stage of exposure to moist air with sulfur dioxide. A cycling corrosion cabinet was used to control 200 ppm gas concentration, relative humidity (RH) and temperature, according to the DIN 50018 (Kesternich test).The method is designed to evaluate how well the surface resists to sulfur dioxide corrosion; the test cycle consists of 8 hours exposure to sulfur dioxide at 40°C temperature and 100% relative humidity, followed by 12 hours drying at room condition. Weight variation, Spectrophotometer, Scanning Electron Microscopy with X-ray microanalysis (SEM-EDS), X-ray Diffraction (XRD) analysis were carried out for the tarnish products characterization. Some of the compound identified were brochantite (Cu4(OH)6SO4), chalcanthite (CuSO4•5H2O) cuprite (Cu2O), cassiterite (SnO2) and ottemannite (Sn2O3).

scholarly journals Crystallization of Random Metallocene-Catalyzed Propylene-Based Copolymers with Ethylene and 1-Hexene on Rapid Cooling

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2091
Author(s):  
Daniela Mileva ◽  
Jingbo Wang ◽  
René Androsch ◽  
Katalee Jariyavidyanont ◽  
Markus Gahleitner ◽  
...  
Keyword(s):  
Mechanical Performance ◽  
Metallocene Catalyst ◽  
Nucleating Agent ◽  
Random Copolymers ◽  
Rapid Cooling ◽  
Significant Difference ◽  
Chip Calorimetry ◽  
High Cooling Rates ◽  
Fast Scanning Chip Calorimetry

Propylene-based random copolymers with either ethylene or 1-hexene as comonomer, produced using a metallocene catalyst, were studied regarding their crystallization behaviors, with a focus on rapid cooling. To get an impression of processing effects, fast scanning chip calorimetry (FSC) was used in addition to the characterization of the mechanical performance. When comparing the comonomer type and the relation to commercial grades based on Ziegler–Natta-type catalysts, both an interaction with the catalyst-related regio-defects and a significant difference between ethylene and 1-hexene was observed. A soluble-type nucleating agent was found to modify the behavior, but to an increasingly lesser degree at high cooling rates.

scholarly journals Editorial for Special Issue “Historical Mineral Pigments”

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 237
Author(s):  
Carolina Cardell ◽  
Jose Santiago Pozo-Antonio
Keyword(s):  
Chemical Characterization ◽  
Glass Enamel ◽  
Special Issue ◽  
High Quality ◽  
Physical Chemical ◽  
Scientific Disciplines ◽  
Natural And Synthetic

The physical–chemical characterization of natural and synthetic historical inorganic and mineral pigments, which may be found embedded in paintings (real or mock-ups), glass, enamel, ceramics, beads, tesserae, etc., as well as their alteration under different decay scenarios, is a demanding line of investigation. This field of research is now both well established and dynamic, as revealed by the numerous publications in high-quality journals of varied scientific disciplines. [...]

scholarly journals Experimental Evaluation of Shear Behavior of Stone Masonry Wall

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2313
Author(s):  
Maria Luisa Beconcini ◽  
Pietro Croce ◽  
Paolo Formichi ◽  
Filippo Landi ◽  
Benedetta Puccini
Keyword(s):  
Shear Behavior ◽  
Stone Masonry ◽  
Masonry Walls ◽  
Mechanical Parameters ◽  
In Situ Tests ◽  
Capacity Curves ◽  
Historical Structures ◽  
Definition Of

The evaluation of the shear behavior of masonry walls is a first fundamental step for the assessment of existing masonry structures in seismic zones. However, due to the complexity of modelling experimental behavior and the wide variety of masonry types characterizing historical structures, the definition of masonry’s mechanical behavior is still a critical issue. Since the possibility to perform in situ tests is very limited and often conflicting with the needs of preservation, the characterization of shear masonry behavior is generally based on reference values of mechanical properties provided in modern structural codes for recurrent masonry categories. In the paper, a combined test procedure for the experimental characterization of masonry mechanical parameters and the assessment of the shear behavior of masonry walls is presented together with the experimental results obtained on three stone masonry walls. The procedure consists of a combination of three different in situ tests to be performed on the investigated wall. First, a single flat jack test is executed to derive the normal compressive stress acting on the wall. Then a double flat jack test is carried out to estimate the elastic modulus. Finally, the proposed shear test is performed to derive the capacity curve and to estimate the shear modulus and the shear strength. The first results obtained in the experimental campaign carried out by the authors confirm the capability of the proposed methodology to assess the masonry mechanical parameters, reducing the uncertainty affecting the definition of capacity curves of walls and consequently the evaluation of seismic vulnerability of the investigated buildings.

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