Effect of Aggregate Type on Properties of Natural Hydraulic Lime-Based Mortars

2017 ◽  
Vol 908 ◽  
pp. 35-39 ◽  
Author(s):  
Martin Vyšvařil ◽  
Tomáš Žižlavský ◽  
Štěpán Zimmermann ◽  
Patrik Bayer
Keyword(s):  
Frost Resistance ◽  
Total Porosity ◽  
Hydraulic Lime ◽  
Limestone Aggregate ◽  
Natural Hydraulic Lime ◽  
Detailed Characteristic ◽  
Restoration Practice ◽  
Limestone Fines ◽  
Mechanical Strengths

In the current restoration practice, the mortars based on aerial or hydraulic lime with siliceous aggregate are used on repair / reconstruction of historical plasters. The resulting properties of lime mortars do not depend only on the type of aggregate, but also on its contamination, origin and a degree of hardening. For this reason, it is needed to know a detailed characteristic of the aggregate and the results obtained for the particular aggregate cannot be generally applied for the similar type of aggregate. This work presents the applicability of Czech local crushed limestone aggregate and limestone fines as a filler to natural hydraulic lime-based mortars. The role of aggregate and limestone fines on the properties of mortars is examined by comparing the mechanical strengths, porosity and frost resistance of the mortars with pure quartz sand and limestone aggregate and its quantity in the mortar. It was found that the limestone aggregate has produced lower strengths, higher total porosity of natural hydraulic lime-based mortars. It has resulted in low frost resistance of the mortars.

Influence of the Aggregate Type on the Properties of Dolomitic Lime-Based Mortars

2016 ◽  
Vol 722 ◽  
pp. 343-350 ◽  
Author(s):  
Martin Vyšvařil ◽  
Tomáš Žižlavský ◽  
Patrik Bayer
Keyword(s):  
Positive Impact ◽  
Total Porosity ◽  
Strength Properties ◽  
Carbonation Reaction ◽  
Dolomitic Lime ◽  
Limestone Aggregate ◽  
Lime Mortars ◽  
Restoration Work ◽  
Limestone Fines

Considering the requirement of numerous restoration work on historical buildings with dolomitic lime-based mortars, a research of the applicability and suitability of various types of plasters for repairing the historical plasters have been developed. This work presents the applicability of limestone aggregate and limestone fines to dolomitic lime-based mortars. The role of aggregates on the properties of dolomitic lime mortars was examined by comparing pure quartz sand and limestone aggregate and its quantity in the mortar. Limestone aggregate and limestone fines accelerated the carbonation reaction in the mortars, but the positive impact of limestone aggregates to strength properties of mortars was not observed. Mortars with limestone aggregate showed higher total porosity and water absorption than those with quartz aggregate. Similar results was obtained for mortars with limestone fines. It was found that limestone aggregate and limestone fines, used in this work, is not so suitable and applicable to the dolomitic lime-based mortar as to the aerial lime-based mortars.

The Effect of Aggregate Type on the Properties of Lime Mortars

2016 ◽  
Vol 861 ◽  
pp. 141-148 ◽  
Author(s):  
Martin Vyšvařil ◽  
Tomáš Žižlavský ◽  
Patrik Bayer
Keyword(s):  
Mechanical Properties ◽  
Absorptive Capacity ◽  
Building Materials ◽  
Historical Buildings ◽  
Limestone Aggregate ◽  
Lime Mortars ◽  
Restoration Work ◽  
Limestone Fines ◽  
Dramatic Growth

Lime mortars represent indispensable building materials that have been used for centuries in civil engineering. Considering the necessity of numerous restoration work on historical buildings, a research of the applicability and suitability of various types of plasters for repairing the historical plasters has been developed. This work presents the applicability of limestone aggregate and limestone fines to aerial lime-based mortars. The role of aggregates on the properties of lime mortars is examined in this paper by comparing pure quartz sand and limestone aggregate and its quantity in the mortar. It was found that limestone aggregate produced the comparable or higher mortar strengths than quartz aggregate and slightly increased porosity, water absorptive capacity and carbonation rate of the mortars. Partially replacement of aggregate by limestone fines has caused dramatic growth in strength, especially in mortars with high content of binder. The applied limestone aggregate is convenient to lime-based mortars and the addition of limestone fines contributes to better mechanical properties of lime mortars.

scholarly journals Cellulose ethers as water-retaining agents in natural hydraulic lime mortars

2019 ◽  
Author(s):  
Martin Vyšvařil ◽  
Patrik Bayer
Keyword(s):  
Water Absorption ◽  
Liquid Water ◽  
Frost Resistance ◽  
Water Retention ◽  
Point Of View ◽  
Cellulose Ethers ◽  
Water Absorption Coefficient ◽  
Hydraulic Lime ◽  
Air Content ◽  
Natural Hydraulic Lime

Cellulose ethers (CEs) are commonly used as viscosity enhancing, water retaining agents in cement-based mortars. Nevertheless, studies about the effect of CEs on the properties of natural hydraulic lime-based mortars (NHL) are absent, although the use of mortars with hydraulic lime is often preferred for renovation purposes. In this study, the behavior of NHL mortars modified by four different CEs is assessed. The fresh state of mortars was characterized by water retention, air content, density a consistency. Hardened mortars were submitted to strength determination, study of pore size distribution, and thermogravimetric analyses. Transport of liquid water in the studied materials was characterized by water absorption coefficient, sorptivity, and liquid water diffusivity. Durability of the prepared mortars was monitored by frost-resistance tests. The results revealed elevated air content and water retention in mortars with increasing dose of CEs resulting in decreased density of fresh mortars. The strengths of modified mortars surpassed the reference ones at age of 180 d despite the fact that the mortars showed higher open porosity and water absorption. Enhanced porosity of mortars resulted in improvement of their frost resistance and faster carbonation. From a practical and economical point of view, the CEs dosage of 0.5% by weight of the binder appears to be sufficient.

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.

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.

scholarly journals Influence of the addition of carbon fibers on the properties of hydraulic lime mortars: comparison with glass and basalt fibers

2020 ◽  
Vol 70 (340) ◽  
pp. 229
Author(s):  
A. Bustos ◽  
E. Moreno ◽  
F. González ◽  
A. Cobo
Keyword(s):  
Carbon Fibers ◽  
Negative Impact ◽  
Void Content ◽  
Historic Buildings ◽  
Basalt Fibers ◽  
Architectural Heritage ◽  
Hydraulic Lime ◽  
Lime Mortars ◽  
Air Void ◽  
Mechanical Strengths

In recent years, the use of hydraulic lime in conservation and restoration of historic buildings has increased due to the pathological processes involved in the use of Portland cement. This investigation deter­mines the properties of hydraulic lime mortars with added carbon fibers for their possible use in restoration of architectural heritage. The results obtained are compared with mortars to which glass and basalt fibers have been added. The results show that the fibers affect significantly the behaviour of the mortar. Although the fibers have a negative impact in the workability and increase the air void content, they improve significantly the mechanical strengths. Although no relevant differences have been found in the pre-cracking behaviour, it has been proven that the fibers avoid a fragile behaviour of the mortar, showing a better post-cracking behaviour. Mortars with carbon fibers are the ones that show the best performance, increasing the toughness up to 12080% over the reference mortars.

Eucalyptus Physiology. III. Frost Resistance.

1981 ◽  
Vol 29 (6) ◽  
pp. 675 ◽  
Author(s):  
DM Paton
Keyword(s):  
Frost Resistance ◽  
Eucalyptus Species ◽  
Supporting Evidence ◽  
Light Conditions ◽  
Root Temperature ◽  
Resistant Species ◽  
Electron Transport Properties ◽  
Active Electron ◽  
The Relationship

The effects of different hardening regimes were studied in E. viminalis by varying temperature, light conditions and photoperiod. The role of root temperature in dehardening was investigated in E. grandis. The relationship between leaf glaucousness and frost resistance was reexamined in E. urnigera and in crosses between the glaucous frost-resistant species E. pulverulenta and the green. less-resistant species E. grandis. These studies involved seedlings but adult material was also used when checking the association between frost resistance and G, the growth regulator in E. grandis. Provided that night temperatures were close to freezing, rapid hardening was independent of photoperiod, light source and day/night temperature differentials. No significant relationship between level of frost resistance and intensity of leaf glaucousness was observed in a segregating progeny of E. urnigera. In F2 and backcross progenies between E. pulverulenta and E. grandis, no evidence was obtained for either physiological or genetical links between glaucousness and frost resistance. As in several other Eucalyptus species, low root temperatures delayed rapid dehardening in E. grandis. Increased frost resistance towards the top of E. grandis seedlings was associated with marked ontogenetic increases in G content. The G content of a 2 m sapling was highest in winter when maximum frost resistance had developed. This and other supporting evidence suggests that G has a role in the frost resistance of E. Grandis perhaps by affecting active electron transport properties of membranes. No information of this kind is available for other Eucalyptus species.

scholarly journals Influence of Restrained Condition on Mechanical Properties, Frost Resistance, and Carbonation Resistance of Expansive Concrete

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2136
Author(s):  
Nguyen Duc Van ◽  
Emika Kuroiwa ◽  
Jihoon Kim ◽  
Hyeonggil Choi ◽  
Yukio Hama
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Frost Resistance ◽  
Total Porosity ◽  
Length Change ◽  
Ratio Test ◽  
Expansive Concrete ◽  
Restrained Condition ◽  
Carbonation Resistance ◽  
Compressive Strength Test

This paper presents the results of an experimental investigation of the effect of the restrained condition on the mechanical properties, frost resistance, and carbonation resistance of expansive concrete with different water–binder ratios. In this study, length change ratio test, expansion strain test, compressive strength test, mercury intrusion porosimetry test, underwater weighing test, freezing–thawing test, and accelerated carbonation test were performed to evaluate the mechanical properties, pore size distribution, total porosity, and durability of expansive concrete under both restrained and unrestrained conditions. The test results indicate that the length change ratio and expansion strain of the expansive concrete were controlled by the restrained condition. The compressive strength of expansive concrete was enhanced by the triaxial restraining when the amount of expansive additive was 40 kg/m3 of concrete. Two hypotheses were described to explain the change of pore structure change expansive mortar. The results also indicate that the carbonation resistance and frost resistance were improved by the uniaxial restrained condition. Furthermore, the effect of the restrained condition must be considered to evaluate not only the experimental results of the expansive concrete with a high EX replacement level but also the expansive concrete combining other cement replacement materials.

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