scholarly journals Effect of Aggregate and Binder Type on the Functional and Durability Parameters of Lightweight Repair Mortars

2021 ◽  
Vol 13 (21) ◽  
pp. 11780
Author(s):  
Martina Záleská ◽  
Milena Pavlíková ◽  
Martin Vyšvařil ◽  
Zbyšek Pavlík
Keyword(s):  
Water Vapor ◽  
Salt Crystallization ◽  
Porous Space ◽  
High Porosity ◽  
Lightweight Aggregates ◽  
Expanded Perlite ◽  
Hydraulic Lime ◽  
Natural Hydraulic Lime ◽  
Binder Type ◽  
Repair Mortars

The subject matter of the work presented here is the development and evaluation of novel lightweight mortars that meet the functional and technical criteria imposed on repair mortars. In a broad experimental campaign, lime, natural hydraulic lime, and lime–cement mortars were designed and tested. Lightweight aggregate, expanded perlite, granules from expanded glass and zeolite were used as full replacements for quartz sand. The hardened mortars were tested at the ages of 28 days and 90 days. The conducted tests and analyses were focused on the assessment of structural, mechanical, hygric and thermal parameters. The salt crystallization resistance and effect of salt presence on the hygroscopicity of the investigated mortars were also investigated. The use of lightweight aggregates in the composition of mortars resulted in their high porosity, low density, satisfactory mechanical parameters, improved water vapor transmission capability and water absorption. The mortars with expanded perlite and glass granulate were ranked among thermal insulation mortars of classes T1 and T2, respectively. The use of lightweight aggregates enabled the development of mortars with great durability in terms of salt action, which was almost independent of binder type. The ability to accommodate water vapor was increased by the effect, i.e., the use of lightweight aggregates and the presence of salt in mortars increased porous space. Taking into account the compatibility, functional, and technical criteria, lime- and natural hydraulic lime-based lightweight mortarswere classified as repair mortars, providing improved thermal performance. The lime–cement lightweight plasters can be recommended only for repair of building structures where cement and lime–cement materials were original applied.

scholarly journals Zeolite Lightweight Repair Renders: Effect of Binder Type on Properties and Salt Crystallization Resistance

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3760
Author(s):  
Milena Pavlíková ◽  
Adéla Kapicová ◽  
Adam Pivák ◽  
Martina Záleská ◽  
Michal Lojka ◽  
...  
Keyword(s):  
Water Vapor Permeability ◽  
High Water ◽  
Salt Crystallization ◽  
Vapor Permeability ◽  
High Porosity ◽  
Water Absorption Coefficient ◽  
Hydraulic Lime ◽  
Technical Parameters ◽  
Natural Hydraulic Lime ◽  
High Sorption

Rendering mortars with lightweight zeolite aggregates were designed and tested. The effect of the type of binder used was also researched. For the hardened mortars, macrostructural parameters, mechanical characteristics, hygric and thermal properties were assessed. Specific attention was paid to the analysis of the salt crystallization resistance of the developed rendering mortars. Quartz sand was fully replaced in the composition of mortars with zeolite gave materials with low density, high porosity, sufficient mechanical strength, high water vapor permeability and high water absorption coefficient, which are technical parameters required for repair rendering mortars as prescribed in the WTA directive 2-9-04/D and EN 998-1. Moreover, the zeolite enhanced mortars exhibit good thermal insulation performance and high sorption capacity. The examined rendering mortars were found to be well durable against salt crystallization, which supports their applicability in salt-laden masonry. Based on the compatibility of the repair materials with those originally used, the lime and natural hydraulic lime zeolite mortars can be used as rendering mortars for the repair of historical and heritage buildings. The cement-lime zeolite render is applicable for repair purposes only in the case of the renewal of masonry in which Portland cement-based materials were originally used.

scholarly journals Lightweight Vapor-Permeable Plasters for Building Repair Detailed Experimental Analysis of the Functional Properties

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2613
Author(s):  
Martina Záleská ◽  
Milena Pavlíková ◽  
Adam Pivák ◽  
Anna-Marie Lauermannová ◽  
Ondřej Jankovský ◽  
...  
Keyword(s):  
Added Value ◽  
Salt Crystallization ◽  
Mechanical Resistance ◽  
High Porosity ◽  
Transport Parameters ◽  
Culture Heritage ◽  
Heritage Buildings ◽  
Historical Culture ◽  
Materials Used ◽  
Repair Mortars

Three types of lightweight plasters for building repair were prepared and tested. The composition of plasters was designed in respect to their compatibility with materials used in the past in historical masonry. For the hardened plasters, detailed testing of microstructural and macrostructural parameters was realized together with the broad experimental campaign focused on the assessment of mechanical, hygric, and thermal properties. As the researched plasters should find use in salt-laden masonry, specific attention was paid to the testing of their durability against salt crystallization. The mechanical resistance, porosity, water vapor transmission properties, and water transport parameters of all the researched plasters safely met criteria of WTA directive 2-9-04/D and standard EN 998-1 imposed on repair mortars. Moreover, the tested materials were ranked as lightweight plasters and due to their low thermal conductivity they can be used for the improvement of thermal performance of repaired masonry. The salt crystallization test caused little or no damage of the plasters, which was due to their high porosity that provided free space for salt crystallization. The developed plasters can be recommended for application in repair of damp and salt masonry and due to their compatible composition also in historical, culture heritage buildings. The added value of plasters is also their good thermal insulation performance.

scholarly journals Mortars with Crushed Lava Granulate for Repair of Damp Historical Buildings

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3557 ◽  
Author(s):  
Zbyšek Pavlík ◽  
Jaroslav Pokorný ◽  
Milena Pavlíková ◽  
Lucie Zemanová ◽  
Martina Záleská ◽  
...  
Keyword(s):  
Mechanical Performance ◽  
Structural Parameters ◽  
Hydrated Lime ◽  
Performance Criteria ◽  
Silica Sand ◽  
Sieve Analysis ◽  
Hydraulic Lime ◽  
X Ray ◽  
Natural Hydraulic Lime ◽  
Repair Mortars

In this paper, crushed lava granulate was used as full silica sand replacement in composition of repair mortars based on hydrated lime, natural hydraulic lime, or cement-lime binder. Lava granules were analyzed by X-ray fluorescence analysis (XRF), X-ray diffraction (XRD), and scanning electron microscopy (SEM). Particle size distribution of both silica and lava aggregates was assessed using standard sieve analysis. Hygrothermal function of the developed lightweight materials was characterized by the measurement of complete set of hygric, thermal, and structural parameters of the hardened mortar samples that were tested for both 28 days and 90 days cured specimens. As the repair mortars must also meet requirements on mechanical performance, their compressive strength, flexural strength, and dynamic Young’s modulus were tested. The newly developed mortars composed of lava aggregate and hydrated lime or natural hydraulic lime met technical, functional, compatibility, and performance criteria on masonry and rendering materials, and were found well applicable for repair of historically valuable buildings.

scholarly journals Bond Properties of NHL-Based Mortars with Viscosity-Modifying Water-Retentive Admixtures

Minerals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 685
Author(s):  
Tomáš Žižlavský ◽  
Patrik Bayer ◽  
Martin Vyšvařil
Keyword(s):  
Water Content ◽  
Adhesive Strength ◽  
Water Retention ◽  
Minor Role ◽  
Clay Brick ◽  
Hydraulic Lime ◽  
Natural Hydraulic Lime ◽  
Binder Ratio ◽  
Paste Viscosity ◽  
A Minor

This article studies the influence of biopolymeric viscosity-modifying admixtures with water-retentive function on the physico-mechanical properties of natural hydraulic lime-based mortars and their adherence to the traditional fired-clay brick substrate. The use of admixtures increases the water/binder ratio, which in turn leads to a decrease in the strength of the mortars. The viscosity-modifying function improves the adhesive strength between mortar and pre-wetter brick by increasing the binder paste viscosity, while the water-retentive function along with increased water content may lead to a decrease in adhesive strength. On the contrary, water retention and increased water content are beneficial on a dry surface, while paste viscosity plays only a minor role. When subjected to temperature-varying cycles, the mortars are more prone to in-mortar failure during the pull-off test. The air-entraining function of some admixtures improves the frost resistance of the mortars; however, it would negatively affect the adhesive strength by incorporating pores into the contact zone between the mortar and brick substrate. This study showed that the use of some of the studied admixtures may improve the adhesion of mortar to the brick substrate.

Polyurethane Electrospun Fiber Biomimetics Membrane for Constructing the Structure of Grain Layer with Good Breathability for Cattle Split Leather

2021 ◽  
Vol 116 (8) ◽  
Author(s):  
Nan Chen ◽  
Yanchun Li ◽  
Jianbo Qu ◽  
Jian-Yong Wang
Keyword(s):  
Water Vapor ◽  
Electrospun Fiber ◽  
Water Vapor Permeability ◽  
Waterborne Polyurethane ◽  
Vapor Permeability ◽  
High Porosity ◽  
Foam Layer ◽  
Fiber Morphology ◽  
Woven Structure ◽  
Superfine Fiber

The traditional thick coating on split leather does not have the ability to breathe like full grain leather.  The air and water vapor permeabilities of full grain leather are well known properties due to its fiber woven structure. Simulating the fiber morphology and weaving structure of the dermis or grain layer is very important to construct a top surface layer for split leather. In this paper, a PU (polyurethane) foam layer is put first on the split to enhance the adhesion of a second application of a superfine fibrous PU resin. This foam uses well-known waterborne polyurethane foaming technology. This dried foam has good breathability because of high porosity. A superfine fiber membrane is next put atop of the foam layer by using an electro-spun polyurethane resin. This second resin imitates collagen fibers in the network structure of the leathers’ grain layer. Thus, this resultant electrospun fiber biomimetics membrane simulated the grain layer of natural leather. SEM showed the morphology and structure of this electrospun fiber biomimetic membrane to be like that of the grain layer of natural leather. The porosity and apparent density were basically the same as the grain of leather, which were 63.65% and 583.878 kg/m3 respectively. The air and water vapor permeability of the biomimetics membrane were also as high as 2250 mL·cm-2·h-1 and 8753.02 μg·cm-2·h-1 respectively. Therefore, the biomimetics membrane largely restored the ability to breathe of split leather. Thus, this method simulates the performance and structure of full grain leather and is a novel method for industrial production

Influence of Sample Thickness and Capping on Characterization of Bedding Mortars from Historic Masonries by Double Punch Test (DPT)

2014 ◽  
Vol 624 ◽  
pp. 322-329 ◽  
Author(s):  
Enrico Sassoni ◽  
Elisa Franzoni ◽  
Claudio Mazzotti
Keyword(s):  
Compressive Strength ◽  
Poor Quality ◽  
Sample Thickness ◽  
Mortar Sample ◽  
Hydraulic Lime ◽  
Punch Test ◽  
Natural Hydraulic Lime ◽  
Wide Range ◽  
Surface Capping

For determination of compressive strength of bedding mortar used in historic masonries, a promising moderately-destructive technique is double punch test (DPT). DPT consists of loading prismatic samples of mortar (about 4×4×1 cm3) by means of two circular steel platens (typically 2 cm diameter) and then calculating mortar compressive strength as the ratio of the failure load to the cross section of the circular platens. In this study, the influence of mortar sample thickness and mortar sample capping on the reliability of results obtained by DPT was systematically investigated. The influence of sample thickness was assessed by comparing DPT results obtained for samples with 5, 10, 15 and 20 mm thickness with compressive strength determined by testing reference 4 cm-side cubes. Different mortars were considered (cement, lime-cement, natural hydraulic lime), in order to investigate a wide range of mortar mechanical characteristics. The influence of surface capping was evaluated on a lime-cement mortar by comparing compressive strength determined on reference cubes with strength obtained by DPT on proper samples, without capping and after capping with rubber, gypsum and cement. The results of the study indicate that sample thickness substantially influences mortar compressive strength determined by DPT, which may vary by up to three times depending on sample thickness. A good estimation of the actual mortar compressive strength was obtained when samples with thickness similar to the loading platens diameter were tested, which suggests that choosing the size of the loading platens for DPT based on the thickness of mortar joints under investigation may be an effective way for obtaining reliable estimations. As for the influence of surface capping, in those cases where no mortar sample regularization is possible, because of the poor quality of the mortar, the results of the study indicate that sample capping actually seems necessary in order to avoid significant underestimations of mortar compressive strength. Considering the higher practicality offered by gypsum with respect to rapid-setting cement for surface capping, the use of gypsum seems preferable.

Design and evaluation of restoration mortars for historic masonry using traditional materials and production techniques

2002 ◽  
Vol 712 ◽  
Author(s):  
Antonia Moropoulou ◽  
Asterios Bakolas ◽  
Petros Moundoulas ◽  
Eleni Aggelakopoulou ◽  
Sofia Anagnostopoulou
Keyword(s):  
Mechanical Strength ◽  
Water Absorption ◽  
Mechanical Tests ◽  
Hydraulic Lime ◽  
Historic Masonry ◽  
Natural Hydraulic Lime ◽  
Total Percentage ◽  
Lime Mortars ◽  
Production Techniques ◽  
Absorption Measurements

ABSTRACTCement based mortars used for historic masonry restoration presented unsatisfactory results, due to their chemical and physico-mechanical incompatibility to original buildings. In the present research, several syntheses of restoration mortars are produced using traditional techniques and materials such as binders (aerial and natural hydraulic lime), pozzolanicadditives (natural and artificial pozzolanas) and aggregates (sand and crushed brick). The technical characteristics of the mortars were determined using mechanical tests (compressive and flexural) and mercury intrusion porosimetry measurements at the time of 1, 3, 9, 15 months of curing. Water absorption measurements were performed at the time of 9 and 15 months curing, in order to evaluate mortars microstructural characteristics, their rate of water absorption and the total percentage of absorbed water. The aerial lime - artificial pozzolana mortar presented the best mechanical and microstructural performance. Hydraulic mortars acquired the maximum of the mechanical strength in 1 month, lime - pozzolana mortars in 3 months while aerial lime mortars continue to gain mechanical strength even in 15 months curing. Furthermore, the use of ceramic aggregates produces lightweight and elastic mortars, compatible to historicones.

Shaking Table Tests on Multi-Leaf Stone Masonry Structures: Analysis of Stiffness Decay

2010 ◽  
Vol 133-134 ◽  
pp. 647-652 ◽  
Author(s):  
Nicola Mazzon ◽  
Cano M. Chavez ◽  
Maria Rosa Valluzzi ◽  
F. Casarin ◽  
Claudio Modena
Keyword(s):  
Dynamic Behaviour ◽  
Shaking Table ◽  
Stone Masonry ◽  
Mode Shapes ◽  
Masonry Structures ◽  
Shaking Table Tests ◽  
Grout Injection ◽  
Hydraulic Lime ◽  
Natural Hydraulic Lime ◽  
Before And After

The influence of the natural hydraulic lime-based grout on the dynamic behaviour of injected multi-leaf stone masonry elements is discussed in the paper. Shaking table experiments on two stone masonry buildings, tested before and after grout injection, have been performed. The paper focuses on the analysis of both the recorded accelerations and related displacements, at the bottom and at each further storey. This leads to evaluate the stiffness of the unstrengthened and injected structures. The input at increasing PGA allowed the stiffness decay to be studied, simulating a gradual damaging of the structures. These results were also interpreted in the light of both computed frequencies and mode shapes. Finally, the comparison among these results, obtained from all the models, allows to deepen the knowledge concerning the effects induced by the lime-based grout injection and on its capability to modify the dynamic behaviour, when intervening on a damaged (repairing) or on an undamaged (strengthening) structure.

Sign in / Sign up

Export Citation Format

Share Document