Cold Regions Science and Technology 68 (2011) 124–129

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Cold Regions Science and Technology

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Effects of surface-finishing forms and cement-filling on porous dimension limestonedeterioration in cold regions

Zeki Karaca a,⁎, Nimet Öztank b, Mehmedi Vehbi Gökçe c, Hakan Elçi d

a Niğde University, Engineering Faculty, Department of Mining Engineering, Niğde, Turkeyb Dokuz Eylül University, Torbalı Vocational Sc, Natural Building Stones Tech. Program, Izmir, Turkeyc Niğde University, Niğde Voc. School of Technical Sciences, Dep. of Construction, Niğde, Turkeyd Dokuz Eylül University, Torbalı Vocational School, Geotechnical Program, Izmir, Turkey

⁎ Corresponding author. Tel.: +90 388 225 2297; faxE-mail address: zkaraca@nigde.edu.tr (Z. Karaca).

0165-232X/$ – see front matter © 2011 Elsevier B.V. Adoi:10.1016/j.coldregions.2011.06.006

a b s t r a c t

a r t i c l e i n f o

Article history:Received 15 February 2011Accepted 12 June 2011

Keywords:Porous limestoneFreeze–thawCement-fillingStone surface-finishing formDeterioration

This work studies the influences of both surface-finishing forms and cement-filling on the durability ofdimension limestone in cold regions. Freeze–thaw cycles, aqueous saline solution and their interactions withsurface-finishing forms and cement-filling on stones were investigated for two types of porous limestone,Caribbean and Pewter Blend. Both deionised water and saline water composed of 20% NaCl by weight wereused, and 28 freeze–thaw cycles were applied to the samples. The change in dry weight, porosity, and Böhmeabrasion loss value was obtained for all test samples. It was observed that two types of porous limestone withcement-filling and different types of surface-finishing were influenced to different extents by freeze–thawand salt. Experiments showed that stones to be used outdoors in cold regions should have relatively low initialporosity and that they should be fine-finished and cement-filled; these modifications to the stones willmaximise the benefit received from the stones.

: +90 388 225 0112.

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© 2011 Elsevier B.V. All rights reserved.

1. Introduction

The development of design tools for the assessment of risk fromfrost and salt decay is important because the freezing and thawing ofporous stonematerials represents a significant challenge in the designand construction of building enclosures in cold regions such asCanada, Finland and Russia. This challenge also exists for high-altituderegions of some countries such as northern regions of America andeastern regions of Turkey.

Porous limestone are processed and marketed as either “unfilled”or “filled”. To provide structural integrity, and thus a uniform surface,the pores on the surface of the stones are filled with filling materialsuch as cement, epoxy, mastic or polyester resins. Alternatively,different surface-finishing forms such as saw–cut (as-sawn), honed,matte, fine-polished, brushed or antique (tumbled) are applicable tonatural building stones.

In cold regions, two significant determinants of damage arefreeze–thaw cycles and salt exposure. At low temperatures, whenporous stone is frozen, water stored in micropores undergoes anexpansion of 9% in volume (Scherer, 1999). This expansion leads tofrost damages that vary from surface scaling to complete disintegra-tion as ice takes shape. Repeated freeze and thaw cycles causeprogressive damage, as thaws lead to the migration of water to

locations where it can freeze. The freeze may introduce fine crackswhere water might have been located during the previous thaw.Subsequent freeze and thaw cycles gradually enlarge cracks untilvisible damage occurs. Thus, it can be inferred that the most reliableway of ensuring frost resistance of any porous material is by reducingthe volume of capillary pores (Lisø et al., 2007).

Salt is known to be one of the most destructive agents for porousstones (Angeli et al., 2008; Espinosa Marzal and Scherer, 2008). Asignificant portion of the damage is due to the crystallisation and hydra-tion properties of salt, a hygroscopic agent. The damage is increased bysalt solutions, which become trapped in the pores of materials. Indeed,water plays an important role as it introduces salt into the medium andcarries it inside materials (Espinosa et al., 2008). Crystallisation pressureresults when growing crystals encounter the walls of a pore. Themaximum stress that a crystal of salt can exert is related to the super-saturation of the pore liquid. Lower stress limits are set by the interfacialenergies of the crystals and thewall and of the pore size and thepressurein the liquid (Scherer, 2000). Exposure to saline water may complicatethe freezing process because the salt produces osmotic pressure thatcauses water to move toward the top layer of the slabs, where freezingtakes place (Powers, 1956). Salt is transported into a porous material bydissolving in water. In this case, the salt solution penetrates into thepores, fissures and microfissures of stones. The salt and salt deposits instones may form efflorescence, subefflorescence or crust (López–Acevedo et al., 1997; Moropoulou et al., 2003; Scherer, 1999).

Porosity is an essential parameter for ornamental stone deterio-ration. Stone properties, including the initial porosity, are significant

125Z. Karaca et al. / Cold Regions Science and Technology 68 (2011) 124–129

factors leading to rock failure in cold regions (Amoroso and Fassina,1983; Matsuoka, 1990). If more than 90% of the pore volume is filledwith water, then the expansion of water during freezing will generatepressure (Chen et al., 2004). This expansion induces concentratedtensile stress and damages the micropores (Fitzner and Kownatzki,1991). When the frozen water thaws, water flows through the frac-tured micropores and increases the damage (Scherer, 1999; Takarliet al., 2008).

Outdoor stone flooring damage depends on the daily temperaturechanges, stone type, material properties and salt usage in icy weatherconditions. Many studies have been carried out using experimentallaboratory simulations to assess stone durability against freeze–thawand salt weathering effects. The common procedures used in thesestudies include the use of NaSO4 and MgSO4 as deteriorative agents,which are required to complywith the standards (European Committeefor Standardization, 1999a; RILEM, 1980). The most important justi-fication for why the testing standards require these two agents is thatthey are the salt compounds thatprecipitate fromatmosphericpollutionand act on stones and other building materials (Grossi et al., 2011).

However, a study considering the product characteristics of stonesand the medium conditions in which they are used, thus aiming atextending the lifetime of the porous stones to be used in cold outdoorconditions, has not been conducted yet. In this study, the effects ofsurface-finishing forms and cement-filling on the deterioration ofporous stones were investigated for cold regions. To realisticallysimulate the media in which these stones are used, in contradistinc-tion to the previous studies, NaCl (aqueous saline solution) was usedfor the thaw processes. NaCl was chosen because it is the agent usedexclusively in practice. Two commercially available porous limestone,Caribbean and Pewter Blend (Fig. 1), which are extensively used bothin Turkey and in the world, were selected for the tests.

2. Experimental procedure

In the study, two techniques were applied depending on the liquidused in thawing, both deionised water and saline solution. The stonesampleswere prepared from two different porous limestone: Caribbeanlimestone extracted inManisa and the Pewter Blend extracted in Afyon,Turkey.

Physical properties such as changes in dry weight and porosity arehighly important parameters in certain application areas, dependingon climate. Additionally, the Böhme abrasion loss value has become auniversally accepted measure of quality of stones used for flooringapplications. All these characteristics are important input parametersfor the estimation of support forces in the filling and fixing systems offlooring, as the parameters affect the stone strength and failure de-pending on the climatic and environmental conditions.

The laboratory measurements of the samples included dry weight,open porosity and Böhme abrasion loss value before and after theaccelerated weathering tests. In determining initial physical proper-ties such as real density and total porosity, the pycnometer techniquewas used. For open porosity changes in accelerated weathering tests,

Fig. 1. Location map of Caribbean and Pewter Blend quarries.

the saturation technique was applied using cube samples 70×70×70 mm in dimensions (European Committee for Standardization,1999b). The abrasion loss values of the samples were determinedusing Böhme abrasion equipment. For this test, specimens, 71×71×71 mm in dimensions, were subjected to a pressure of 0.06 N/mm2 ona rotating drum, and an abrasive was added between the sample andthe drum. After 352 rotations, changes in the thickness of the sampleswere recorded and used as the abrasion values. The values were mea-sured according to the methods suggested by EN 14157 (EuropeanCommittee for Standardization, 2004). Uniaxial compressive strengthand tensile strength values of fresh samples of these two stones weredetermined in addition to density, porosity, water absorption atatmospheric pressure and Böhme abrasion loss values.

We performed accelerated ageing tests to quantify the level ofdeterioration in the Caribbean and Pewter Blend. As-sawn, honed,fine-polished, cement-filled as-sawn, cement-filled honed and ce-ment-filled fine-polished specimens were prepared as surface-finish-ing forms (Table 1). Twenty-eight freeze–thaw cycleswere carried outusing deionisedwater and salinewater solution composed of 20%NaClby weight (aqueous saline solution 20% NaCl w/w). The samples werefrozen in a deep-freeze cabinet. During the freeze process, the lowerboundwas set to−20 °C for 18 h. The freezing temperature was set at−20 °C because a solution that is composed of 20% NaCl freezes at−16 °C. During the thaw process, the water temperature (for bothdeionised water and saline) was set to +20 °C for 6 h. Thus, a dailyfreeze–thaw cycle was achieved. For every test cycle, deionised waterand saline were refreshed by renewing the components. All tests wereperformed at room temperature (22±1 °C). The relative humiditywas maintained at 45±5% level during testing.

Twelve powder samples of 10 g, with 6 samples of each limestone,were prepared for real density and total porosity measurements. Themaximum granular sizes of the samples used in these two tests wereless than 63 μm. For apparent density, open porosity, uniaxialcompressive strength, tensile strength and Böhme abrasion valuemeasurements, 10 samples were prepared from each stone. Thus, atotal of 572 samples were prepared, with 92 used for determiningphysico-mechanical properties of fresh samples, and 480 used foraccelerated weathering tests.

After the ageing tests, cross-sections were also examined andphotographed under the scanning electronmicroscope (Jeol–Jsm6060SEM–EDX). A polarisedmicroscope, Olympus BX41TFmodel, was usedfor the petrographic analyses of the tested samples. The petrographicanalyses were executed according to the methods suggested by EN12407 (European Committee for Standardization, 2007). The elemen-tal analyses of the sampleswere performed by the inductively coupledplasmamass spectroscopy (ICP-MS) technique. Finally, the changes indry weights, open porosities and Böhme abrasion loss values werediscussed with regard to the thaw conditions.

3. Results and discussion

For petrographical identification, cross-sections of the Caribbeanand Pewter Blend were studied under a polarising optical microscopebefore the ageing tests were conducted. The Caribbean stone wasobserved to be laminated carbonate mudstone that was partly re-crystallised. The pores were filled with sparite, and local silicificationwas also observed through the pores. The colour was locally reddish

Table 1The product characteristics of the samples.

Samples Surface finishing forms

Caribbean Unfilled Cement-filledAs-sawn Honed Fine-polished As-sawn Honed Fine-polished

PewterBlend

Table 3The initial physico-mechanical properties of Caribbean and Pewter Blend.

Caribbean Pewter Blend

Apparent density, kN/m3 25.44 25.19Real density, kN/m3 27.08 27.10Open porosity, % 1.983 2.177Total porosity, % 6.218 7.208Water absorption at atmospheric pressure, % 0.780 0.869Uniaxial compressive strength, MPa 47.23 19.28Tensile strength, MPa 4.79 2.71Böhme abrasion value, cm3/50 cm2 33.64 37

-0.15

-0.10

-0.05

0.00

0.05

0.10

0.15

Cha

nge

in d

ry w

eigh

t, %

deionised water saline water

126 Z. Karaca et al. / Cold Regions Science and Technology 68 (2011) 124–129

because of iron oxidation. The original texture of the Pewter Blendcould not be determined due to intense recrystallisation. Local sili-cification was also observed throughout the pores of the stone. Theelemental analyses, obtained from inductive coupled plasma massspectroscopy (ICP-MS), are given in Table 1. The summaries of the testsregarding the physical andmechanical properties of fresh samples aregiven in Tables 2 and 3.

In practice, building stones are subject to the impacts of freeze–thaw cycles and salt exposure. They are the most common destructiveagents for porous stones. Several studies have already analysed theinfluence of the freeze–thaw cycles and salt on the durability anddeterioration of stones (Angeli et al., 2008; Honeyborne and Harris,1958; Russell, 1927). Additionally, several investigators have studiedthe effects of weathering on the engineering properties of differenttypes of rocks (Cole and Lancuchi, 1976; Cole and Sandy, 1980;Goodman, 1989; Haskins and Bell, 1995; Lumb, 1983; Moropoulouet al., 2003; Nakamura, 1996).

However, the influence of freeze–thaw cycles and salt exposure onstones that have different surface-finishing forms that are filled orunfilled are still unknown and have not been studied. Therefore, thepurpose of this study was to thoroughly investigate the effects offreeze–thaw cycles and salt exposure on surface-finishing forms andcement-filling to gain a better understanding of these factors on stonedurability. This information can be used to improve the sustainabilityof stone consumption in the construction industry. In this study,accelerated weathering tests were performed on unfilled and cement-filled samples that had as-sawn, honed, and fine-polished surfacefinishing. The prepared cement-filling material consisted of 35%cement, 15% kaolin, and 50% water by weight, a formulation thatsimulates the composition of commercial treatments. The cement-filling was manually applied on all surfaces of the samples. Except forthe as-sawn samples, grinding was also done manually. Grid abrasivetypes 90–120–180–220 and 90–120–180–220–280–320–360–480–600–800 were used for honing and fine-polishing, respectively.

After effect of freeze–thaw cycles on dry weight, porosity and theBöhme abrasion loss value was determined for unfilled and cement-filled samples with different surface- finishing forms. At the end of the28th cycle, all specimens were dried in an oven for 24 h at 105 °C untilall the specimens were free of water, and then, they were cooleddown to room temperature. Before being put in the oven, the speci-mens thawed in saline were washed with pure water to eliminate thecrystals of salt that had accumulated on the surface of the samplesbecause the salt crystals could potentially affect the test results. Thedry weight and porosity changes were calculated at the end of thisstage. Böhme abrasion loss values for unfilled and cement-filledspecimens were also measured for each surface-finishing form afterboth thaw processes. The ageing results, compared with the pro-perties of the fresh specimens, are presented in Figs. 3–8. As expected,Pewter Blend, which had higher initial porosity than Caribbean,proved to be relativelymore influenced by the tests than Caribbean. Ingeneral, with respect to weathering, the saline solution was observedto have influenced the porous stone samples more than the deionisedwater.

Surface-finishing forms and/or cement-filling were determined tohave been effective in freeze–thaw processes. As seen in Figs. 2 and 3,at the end of 28 test cycles, dry weights decreased following the thawprocess in deionised water, although they increased following thethaw process in saline solution. It was concluded that the weightincrease was due to the salt crystals that fit into the pores during the

Table 2Elemental analysis by ICP-MS on Caribbean and Pewter Blend (in wt.%).

SiO2 Al2O3 Fe2O3 MgO CaO Na2O K2O MnO

Caribbean 0.08 0.02 b0.04 0.09 56.44 b0.01 b0.01 0.09Pewter Blend 0.10 0.08 b0.04 0.20 56.77 b0.01 b0.01 b0.01

thawing process in saline solution (Fig. 8). In cement-filled samples,the highest losses in weights were determined in the as-sawnsamples, and the lowest losses were determined in the fine-polishedsamples. The effects of ageingwere increased as the surface roughnessincreased. This pattern was witnessed more clearly in the unfilledsamples that were thawed in deionised water than in those thawed insaline solution. In other samples, the effect of the surface-finishingforms on the change in dry weight could not be determined becausethe amount of disintegration of filling from the cavities, from thefragmentation of stone, and/or from the level of the salt effect was notprecisely calculated. Weight losses in the cement-filled, as-sawnsamples of Pewter Blend reached up to 0.25% in thaw tests indeionised water.

As expected, porosity values increased in all samples (Figs. 4 and 5and Table 4). After the thaw cycles in saline solution, porosity valueschanged the most distinctly in the unfilled as-sawn samples, withvalues of 2.48% in the Caribbean and 3.05% in the Pewter, whereas theporosity values only increased by 2.16% in the Caribbean and 2.84% inthe Pewter Blend for the same samples thawed in deionised water.The cement-filled fine-polished samples had the lowest increase inporosity, with an increase in porosity of 0.61% for Caribbean and 1.23%for Pewter Blend after being thawed in saline solution. Unexpectedly,the porosity of the cement-filled honed samples thawed in deionisedwater increased more than the porosities of the samples thawed insaline solution did (1.41% and 0.92%, respectively, for Caribbean, and2.24% and 1.40%, respectively, for Pewter Blend). A similar result wasobtained for the cement-filled fine-polished samples of both stones(1.33% for deionisedwater and 0.61% for saline solution for Caribbean;2.20% for deionised water and 1.23% for saline solution for PewterBlend). Furthermore, in cement-filled as-sawn Pewter Blend samplesexposed to either deionised water or saline solution during thethawing process, the porosity values of the samples came out to beequal to each other (2.35% for deionised water and saline solution),whereas the values of in cement-filled as-sawn Caribbean samplesexposed to deionised water or saline solution differed slightly (1.77%for deionised water and 1.81% for saline solution).

-0.20

as-sawn honed fine-polished

cement-filled

as-sawn

cement-filled

honed

cement-filled fine-polished

Surface-finishing form

Fig. 2. Dry weight changes of Caribbean thawed in deionised water and saline solution.

-0.25

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

as-sawn honed fine-polished

cement-fillled

as-sawn

cement-filled

honed

cement-filled fine-

polished

Cha

nge

in d

ry w

eigh

t, %

Surface-finishing form

saline water deionised water

Fig. 3. Dry weight changes of Pewter Blend thawed in deionised water and salinesolution.

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

as-sawn honed fine-polished

cement-filled as-

sawn

cement-filled

honed

cement-filled fine-polished

Cha

nge

in p

oros

ity, %

Surface-finishing form

deionised water saline water

Fig. 5. Porosity changes of Pewter Blend thawed in deionised water and saline solution.

deionised water saline water

127Z. Karaca et al. / Cold Regions Science and Technology 68 (2011) 124–129

As seen in Fig. 9, salt crystals are seen in the gaps between cement-filling and the contours of the pores. This information is compatiblewith the upward changes in dry weights. After the thaw process indeionised water, the dry weight loss was relatively smaller for stoneswith an initially low porosity. Similarly, Böhme abrasion loss valueswere lower for stones with an initially low porosity. Generally, dryweight losses and Böhme abrasion loss values decreased as theporosity did. Among the textural characteristics, porosity proved to beone of the main features determining stone deterioration.

Cement-filling was determined to reduce the effects of freeze–thaw cycles and salt in aged samples. The ratio of porosity changesdecreased as the surface roughness did. Porosity changes in unfilledsamples thawed in saline solution were observed to have increasedmore than those in samples thawed in deionised water. However, incement-filled samples, deionised water affected the changes inporosity more than saline solution did. The reason for this differencein the effect of saline solution and deionised water on filled andunfilled samples is thought to be due to differences in the penetrationcapability of deionised water in the samples. It was observed that thesalt crystals could not advance through the filled stones because thesalt crystals became trapped in the pores on the surfaces of stones aswell as between the contours of the gaps and cement-filling (Fig. 8).Thus, cement-filling was found to have prevented the saline solutionfrom penetrating into the stone and reduced the effects of freeze–thaw cycles in the presence of salt.

Variations of the Böhme abrasion loss values after freeze–thawtests are presented in Figs. 6 and 7. As indicated by the figures, theBöhme abrasion loss values of Caribbean unfilled as-sawn, unfilled

0.0

0.5

1.0

1.5

2.0

2.5

as-sawn honed fine-polished

cement-filled as-

sawn

cement-filled

honed

cement-filled fine-polished

Cha

nge

in p

oros

ity, %

Surface-finishing form

deionised water saline water

Fig. 4. Porosity changes of Caribbean thawed in deionised water and saline solution.

honed, unfilled fine-polished, cement-filled as-sawn, cement-filledhoned and cement-filled fine-polished samples increased by 2.49%,1.92%, 1.06%, 2.29%, 1.87% and 1.06%, respectively, after being thawedin deionised water, whereas the increases for Pewter Blend were4.88%, 4.47%, 4.15%, 4.76%, 4.44% and 4.15%, respectively. Theincreases were 2.49%, 1.98%, 1.12%, 2.29%, 1.92% and 1.06% respec-tively for Caribbean samples thawed in saline water, whereas theywere 5.13%, 4.74%, 4.64%, 4.88%, 4.64% and 4.54%, respectively, forPewter Blend samples.

Similar to the changes in dry weights and porosity values, themaximum increase in the Böhme abrasion loss value was observed inthe unfilled as-sawn samples. The highest losses in abrasion re-sistances were in the Caribbean unfilled as-sawn samples, in whichthe loss was 2.49% for thawing cycles in both deionised and salinewaters. The loss in abrasion resistance was 5.13% for thawing cycles insaline solution in the Pewter Blend unfilled as-sawn samples. On theother hand, the least loss in abrasion resistance was observed in thecement-filled fine-polished samples (1.06% for Caribbean thawedboth in deionised and saline waters and 4.15% for Pewter Blendthawed in deionised water) (Figs. 6 and 7).

As shown in Fig. 6, after 28 test cycles, the Caribbean unfilled as-sawn, cement-filled as-sawn, and cement-filled fine-polished sampleswere determined to be affected at the same ratios in thaw processesboth in deionised water and saline solution. However, unfilled honed,unfilled fine-polished, and cement-filled honed samples weredetermined to have been affected at different ratios in the thawprocesses in deionised water and saline solution. Considering theseresults, effects of surface-finishing forms on aged samples are not

0.0

0.5

1.0

1.5

2.0

2.5

as-sawn honed fine-polished

cement-filled as-

sawn

cement-filled

honed

cement-filled fine-polished

Cha

nge

in B

öhm

e ab

rasi

on lo

ss

valu

e, %

Surface-finishing form

Fig. 6. Böhme abrasion loss value changes of Caribbean thawed in deionised water andsaline solution.

0.0

1.0

2.0

3.0

4.0

5.0

as-sawn honed fine-polished

cement-filled as-

sawn

cement-filled

honed

cement-filled fine-

polished

Cha

nge

in B

öhm

e ab

rasi

on lo

ss

valu

e, %

Surface-finishing form

deionised water saline water

Fig. 7. Böhme abrasion loss value changes of Pewter Blend thawed in deionised waterand saline solution.

Table 4The porosity changes of the samples.

Samples Surface finishing forms

Unfilled Cement-filled

As-sawn

Honed Fine-polished

As-sawn

Honed Fine-polished

Caribbean (thawed indeionised water)

2.16 1.72 1.64 1.77 1.41 1.33

Caribbean (thawed insaline solution)

2.48 2.39 2.44 1.81 0.92 0.61

Pewter Blend (thawed indeionised water)

2.84 2.65 2.06 2.35 2.24 2.2

Pewter Blend (thawed insaline solution)

3.05 2.91 2.8 2.35 1.4 1.23

128 Z. Karaca et al. / Cold Regions Science and Technology 68 (2011) 124–129

clear enough for unfilled as-sawn, cement-filled as-sawn, andcement-filled fine-polished Pewter Blend samples. These resultshave shown that the Böhme abrasion loss value for Pewter Blend isnot a distinctive parameter good enough to compare these ageing testtechniques with respect to surface-finishing forms and cement-filling.

In this paper, freeze–thaw-induced changes in the engineeringproperties of twoporous limestone that haddifferent surface-finishingforms and thatwere cement-filledwere studied for two different thawtechniques, deionised water and aqueous saline solution, 20% salt byweight. Dry weight, porosity and Böhme abrasion loss values of bothCaribbean and Pewter Blend were found to have been affected byageing tests. However, the Böhme abrasion loss value, compared to theother two parameters, was not a distinctive parameter good enough tocompare the ageing techniques implemented in the study. The po-rosity was determined to be an important factor in stone deteriorationbecause the cavities constituting porosity reduced the integrity of thematerial. Pewter Blend (with higher initial porosity than Caribbean)was affected more significantly by the ageing processes. As a result,Pewter Blend limestone was found to be less resistant to salt activitythan Caribbean limestone.

Analyses of the experimental data have shown that the surfaceroughness and cement-filling have an important role on the actions offreeze–thaw and salt on porous limestone. Therefore, in cold regions,for projects in which porous limestone is used for flooring, the use ofstones that are filled and that have low surface roughness and lowporosity should be preferred.

Fig. 8. Salt crystals in pores under SEM.

4. Conclusions

In this study, the effects of surface-finishing forms and cement-filling on dry weights, porosities and Böhme abrasion loss values oftwo types of porous limestone that were exposed to freeze–thaw testswere investigated experimentally. The changes in these propertieswere determined for samples that were exposed to 28 freeze–thawcycles in both deionised water and in a saline solution of 20% NaCl byweight, at temperatures between −20 °C and +20 °C. The results onaged samples showed the following:

• The dry weights of the samples thawed in deionised water weredetermined to have decreased, whereas those of the samplesthawed in saline solution increased.

• Stones that had a higher initial porosity were determined to be lessresistant to deterioration.

• A clear relationship between Böhme abrasion loss values andsurface-finishing forms and between Böhme abrasion loss valuesand cement-filling processes could not be determined after freeze–thaw tests. Therefore, these tests are not suggested for theassessment of stone quality with respect to Böhme abrasion lossvalues in cold regions.

• The influence of freeze–thaw cycles and salt on the ageing of thestones decreased as the surface roughness decreased. Cement-fillingalso decreased the effects of freeze–thaw cycles and salt on porouslimestone.

The relationship between surface-finishing forms (surface rough-ness), cement-filling and freeze–thaw cycles was found to beextremely important for the deterioration of the stones. As a result,

Fig. 9. SEM photomicrograph of salt crystals at the border of cement-filling.

129Z. Karaca et al. / Cold Regions Science and Technology 68 (2011) 124–129

stones scheduled for outdoor use in cold regions should be filled, haveas low surface roughness, and have as little porosity as possible.

Acknowledgements

The authors would like to thank Bilgehan Uysal, Gökcen Aktaş andtheir colleagues in Reisoğlu Marble Co. for their courteous contribu-tions in providing the specimens. The authors are also grateful to Dr.Bilal Sarı for his valuable help in conducting the cross-sections.

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