Abstract:The efficiency of three commercial hydrophobic coatings applied on two types of sandstones was subjected to the tests of water absorption by capillarity, water absorption by complete immersion, and frost resistance. Two days of the curing time of coatings on samples were chosen for the laboratory tests. The effects of the used coatings were different (ambiguous). Two coatings proved their effectiveness and thus, relevance of their use, but different coatings were effective on each type of sandstone. The coatin… Show more
“…The sandstone contains intergranular cement, which is a mixture of kaolinite, illite, and fine quartz grains [22]. The basic physical properties of sandstone are as follows: bulk density ρd = 1930 kg•m −3 , total porosity n = 26%, open porosity no = 18.3%, water absorption NWAI = 9.5-12.2%, and uniaxial compressive strength UCS = 29.9 MPa [20]. The rock material for the research was taken directly from the Podhorní Újezd quarry in the Podkrkonoší area, which is currently the largest sandstone quarry in the Czech Republic.…”
Section: Methodsmentioning
confidence: 99%
“…The efficiency of the coatings applied on the sandstone under the specified conditions was evaluated by checking the depth of penetration into the treated sandstone, as well as by water absorption tests. Mainly tests of the absorption by capillarity were carried out, approved as a suitable method in previous research [19,20].…”
Protecting stone on facades or exterior art works from deterioration is primarily about protecting them from rainwater. Hydrophobic coatings are widely used for this purpose. Here, two factors affecting the long-term efficiency of some coatings applied on stones were investigated: the number of coating layers and the curing time after their application. Tests of water absorption by capillarity, absorption at total immersion in water, and a visual check of the penetration depth have been carried out. The coating’s efficiency coefficient Cef was defined as the ratio of the maximum water absorption of a treated sample to an untreated one. Two commercial silicon-based coatings were applied on the highly porous Hořice sandstone alternatively. Curing times of 2 days vs. 2 weeks, and 2 coating layers vs. 3 layers were compared. The experiments showed that the coating’s efficiency is affected more by the curing time than by the number of applied coating layers. The curing time of 2 days after coating’s application is too short, but 2 weeks proved to be sufficient for both tested coatings. There was no big difference regarding the number of coating layers; two layers seem to be sufficient if a long rain-free curing time can be guaranteed.
“…The sandstone contains intergranular cement, which is a mixture of kaolinite, illite, and fine quartz grains [22]. The basic physical properties of sandstone are as follows: bulk density ρd = 1930 kg•m −3 , total porosity n = 26%, open porosity no = 18.3%, water absorption NWAI = 9.5-12.2%, and uniaxial compressive strength UCS = 29.9 MPa [20]. The rock material for the research was taken directly from the Podhorní Újezd quarry in the Podkrkonoší area, which is currently the largest sandstone quarry in the Czech Republic.…”
Section: Methodsmentioning
confidence: 99%
“…The efficiency of the coatings applied on the sandstone under the specified conditions was evaluated by checking the depth of penetration into the treated sandstone, as well as by water absorption tests. Mainly tests of the absorption by capillarity were carried out, approved as a suitable method in previous research [19,20].…”
Protecting stone on facades or exterior art works from deterioration is primarily about protecting them from rainwater. Hydrophobic coatings are widely used for this purpose. Here, two factors affecting the long-term efficiency of some coatings applied on stones were investigated: the number of coating layers and the curing time after their application. Tests of water absorption by capillarity, absorption at total immersion in water, and a visual check of the penetration depth have been carried out. The coating’s efficiency coefficient Cef was defined as the ratio of the maximum water absorption of a treated sample to an untreated one. Two commercial silicon-based coatings were applied on the highly porous Hořice sandstone alternatively. Curing times of 2 days vs. 2 weeks, and 2 coating layers vs. 3 layers were compared. The experiments showed that the coating’s efficiency is affected more by the curing time than by the number of applied coating layers. The curing time of 2 days after coating’s application is too short, but 2 weeks proved to be sufficient for both tested coatings. There was no big difference regarding the number of coating layers; two layers seem to be sufficient if a long rain-free curing time can be guaranteed.
“…The most important changes are related to the increase in average pore size, which in both cases (ADDs and ADDTs) exceeds 16 µm, possibly because of the removal of the few clays they contain. Also, microporosity increases slightly (> 30%) to the detriment of macroporosity, which remains dominant (60). The geometry of the pores (0.22-0.17 m 2 /g and 1.14 µm) and their capillary connections (tortuosity = 6.6-2.4) become more regular and straighter, establishing a new fissure microporosity -especially in the treated sandstones (ADDTs) -detected by PLM and FLM.…”
Section: Petrophysical Characterisationmentioning
confidence: 98%
“…While vapour permeability is reduced by one third (~1.14•10 -9 kg/m•s•Pa), air permeability is reduced by up to 60% (~316 mD) (Table 5). ESTEL 1100 effectively restricts the ingress of water in this sandstone, but it also restricts its egress by reducing transpiration, which may affect the durability of this material (25,27,60). Salt aggression does not cause significant changes to the structural and hydric properties of the original sandstone (ADD and ADDT; Table 5, Figure 6-8).…”
Sandstones have been widely used in construction for their abundance, aesthetics, and ease of extraction. To determine sandstones’ quality, it is essential to analyse their petrographic and petrophysical properties and sensitivity (durability and conservation) to environmental agents. This paper evaluates the physical-mechanical changes undergone by Sierra de la Demanda (Burgos, Spain) sandstone under combined and induced water and salt aggression and assesses ESTEL 1100’s effectiveness and suitability as a treatment. This sandstone is porous, permeable, dense and quartz-rich with high hardness and strength. The treatment improved its petrophysical properties by modifying its pore geometry and connectivity, reducing absorbency, permeability and anisotropy, and further increasing its hardness and resistance. Salts did not substantially modify its properties as its porosity type absorbed the crystallisation pressure. Ultimately, its pore system and predominantly quartz composition make it a high-quality, weather-resistant material compatible with the treatment applied.
“…Silt is a typical poorly graded soil, which often has the characteristics of poor stability of particle skeleton structure and large capillary porosity. Therefore, the harm of capillary water to silt sites is more serious than that of general soil sites [1,2]. Therefore, it is necessary to study the methods to control the capillary rise in silt sites.…”
Silt has the characteristics of obvious capillary water effect and strong water sensitivity. The flooding of the Yellow River caused the water level in Kaifeng to be high, and the damage of capillary water to the silt site of Kaifeng Zhouqiao site is increasing day by day. In order to improve the waterproof performance of the site soil, three kinds of silicone waterproof materials were selected, and the site soil was improved by internal mixing. The improvement effects of different materials were compared through the capillary water rise test, and the contact angle of the modified soil with the optimal ratio was measured. Microscopic tests were conducted to evaluate its wetting properties and reveal the mechanism of action of the modified materials. The results show that the three kinds of silicone waterproofing agents can improve the waterproofing effect of soil, among which 0.5% sodium methylsilicate modified soil has the most significant waterproofing effect; its capillary water absorption inhibition effect can reach 98.34%, and the contact angle is 137.06. The surface of the modified soil is hydrophobic after the addition of sodium methylsilicate. An evenly distributed waterproof film is thus formed on the surface of the soil particles, which changes the contact mode between the soil particles and strengthens the connection between the soil particles, so that the proportion of large pores decreased. The proportion of mesopores and small pores increased, which made the soil sample more compact. These results explain the improvement of the waterproof performance of the soil sample.
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