The Characteristic of yellow loess plastering with Hanji wallpaper

Transcription

1 The Characteristic of yellow loess plastering with Hanji wallpaper Hongseok Jang Ph.D, Department of Architectural Engineering, Chonbuk National University (RCIT), South Korea. Boram Lee Master, Department of Architectural Engineering, Chonbuk National University, South Korea. Hyeseon Kang Doctor course, of Architectural Engineering, Chonbuk National University, South Korea. Seungyoung So (Corresponding author) Professor, Department of Architectural Engineering, Chonbuk National University, South Korea. Abstract- Yellow loess is a natural construction material used for various purposes, such as deodorant, anti-gas and building materials. The moisture controlling effect of Yellow loess is commonly known, but has not been scientifically proven; the deodorization effect has not been identified, either. This research studied the effect of Hanji wallpaper (Traditional Korean paper handmade from mulberry trees) as a finishing material of Yellow loess material by analyzing the functional characteristics, such as moisture controlling and deodorizing effects of yellow loess plastering. The results indicate that the moisture controlling ability increased with a surge in the thickness of Yellow loess plastering and with Yellow loess + Hanji wallpaper composite specimens showed similar moisture absorption ability as the Yellow loess plastering specimen. And the Yellow loess + Hanji wallpaper composite specimen showed larger quantities of deodorization than the cement mortar specimen. Keywords: Hanji wallpaper, Humidity-controlling, Yellow loss, finishing materials, deodorizing. INTRODUCTION Since 1970s, Korea has achieved rapid economic growth thanks to industrialization, and the subsequently increasing concentration of urban population has resulted in a serious housing shortage problem. Due to a shortage of houses, the nation has continuously increased multi-household houses. As of now, 70% of the nation s population lives in multihousehold houses, the multi-household housing accounts for 80% of the newly-built houses. However, thanks to an enhanced economic level of modern people, they become more conscious of the quality of life. Due to an increasing interest in the tradition, environmentfriendly housing and wellbeing, the number of people who prefer traditional house instead of a uniform and environmentunfriendly multi-household housing. However, as it is impossible to accommodate multiple generations of a family in a single traditional house, we believe that it is more effective in promoting the health of the people to recreate the beneficial effects of traditional house in a typical housing type of modern people. In Korea, loess has been known as a healthy material traditionally, and in everyday life it has been used in various fields [1]. Loess plastering has long been as a common finishing material for floors and walls, as it is easily available and thanks to its various advantages; heat-preserving effect, adsorb ability, deodorizing effect, absorptiveness, dewater ability, far-infrared radiation, deionization, anion generating effect, and de-toxicating effect [2]. As it is recognized as a construction material with a great health-enhancing effect, the demand for loess is on the rise. And the yellow loess culture institute of health promotion was attempted to discuss the efficacy of loess bio-products [3-6]. Clay-based materials show high moisture storage capacity through surface adsorption and capillary condensation effects in the hygroscopic domain. Such phenomena coupled with moisture transport inside the porous structure are stated to offer a regulation capacity of the indoor air humidity [7], improving comfort for occupants [8-10]. This research studied the effect of Hanji wallpaper as a finishing material of Yellow loess material by analyzing the functional characteristics, such as moisture controlling and deodorizing effects of yellow loess plastering. In addition, in order to find out a way of overcoming the shortcomings of yellow loess, which can get easily smeared or chipped off, assessed the moisture controlling and harmful material adsorbing ability after reinforcing it with Hanji wallpaper different plastering material, and would decide on the ideal plastering thickness and material. MATERIALS AND METHODS Materials For this study, the specimens were prepared using the following raw materials. Cement and loess powder Ordinary Portland Cement (OPC) complying with the 8207

2 requirements of Korean standard KS L 5201 and yellowcolored loess powder type of Yellow loess in 325 mesh produced in Gochang, Korea was used. Its chemical composition and physical properties are shown in Table 1. Aggregate The study used the standard sand produced in Jumunjin, which meets the standards of KS F Table 1: Chemical properties of loess powder and cement Components SiO 2 Al 2O 3 Fe 2O 3 CaO K 2O MgO Loess powder Cement Finishing Materials Hanji wallpaper, which is the Korean traditional paper made from mulberry trees. Table 2: Basic properties of Hanji wallpaper Hanji wallpaper Raw ingredients Mulberry tees Thickness (mm) 0.08 Basis weight (g/m 2 ) 25 Production of Specimens Mixing ratio The mixing ratio of cement and aggregate to produce cement mortar was 1:2.45, with the water ratio to cement (w/c) is 45%. When producing yellow loess specimens by adding only water to yellow loess powder, their water ratio was 45% like the cement mortar specimens. Manufacturing of Specimens Cement mortar was mixed in accordance with KS L In regard to the yellow loess block specimens, yellow loess powder and water were mixed, poured into the mold, and then cured. To prepare the yellow loess plastering specimens, the mixture of water and loess powder were plastered onto the prepared cement mortar specimens at varying thicknesses of 1, 2 and 3cm. The specimens used for the moisture-controlling experiment and the ammonia gas deodorizing experiment were produced in 160mm 160mm. However, only 125mm 125mm of a specimen was exposed, while the remaining area was sealed with aluminum foil and aluminum tape. (see Table 3). Type Mo-H Lo-H Pl1-H Pl2-H Pl3-H Table 3: Composition of specimens Composition 4cm-thick cement mortar+hanji Loess block (thickness: 10cm)+Hanji 4cm-mortar+1cm-Loess plastering+hanji 4cm-mortar+2cm-Loess plastering+hanji 4cm-mortar+3cm-Loess plastering+hanji Function assessment of yellow loess Assessment of moisture controlling ability The specimens were dried at a temperature of 105 for 24 hours. Then, after the specimens at the absolute dry condition were placed inside the thermo-hygrostat, their weight change was measured once per day (every 24 hours). When the weight of a specimen stopped increasing, it was defined as the maximum moisture absorption condition. The maximum moisture absorption quantity was calculated by converting the difference between the weight of a specimen at the maximum moisture absorption condition and the absolute dry specific gravity into a value per a unit size (cm 2 ). The specimen at the maximum moisture absorption condition was left inside a room at a temperature of 25 and at RH 25% (see Table 4, Fig 1). When the weight stopped decreasing at a constant weight, it was defined as the maximum moisture desorption condition. The maximum moisture desorption quantity was calculated by converting the difference in weight between the maximum moisture absorption condition and the maximum moisture desorption condition into a value per a unit sixe (cm 2 ). Maximum Moisture Absorption Quantity (g/cm 2 ) = (the weight of a specimen at the maximum moisture absorption condition the absolute dry weight of a specimen) / (exposed area) Maximum Moisture Desorption Quantity (g/cm 2 ) = (the maximum moisture absorption quantity-the maximum moisture desorption quantity) / (exposed area) Figure 1: Analysis of Moisture controlling Experiment Graph Table 4: Composition of moisture controlling ability experiment Moisture absorption process Specimen condition Absolute before experiment condition Moisture desorption process dry Maximum moisture absorption condition Temperature Humidity RH 98% RH 25% Measurement Interval daily (every 24 daily (every 24 hours) hours) Assessment of ammonia gas deodorizing ability by exposure hours The study analyzed the ammonia gas deodorizing ability of specimens by exposure hours. This study conducted a 8208

3 comparative study by using the ammonia experiment method among the odor analysis methods of the National Institute of Environmental Research. In this study, placed the ammonia emission source (12ppm) inside 20L chamber and then sealed it. The chamber was kept in a sealed condition inside a thermo-hygrostat at a temperature of 25 throughout the experiment. After periods of time, collected a total of 25L of ammonia captured in the boric acid solution at 1.5L/min capture by using the MFC pump (See Fig 2). After installing specimens inside the 20L chamber, exposed them to the ammonia solution, and performed a comparative analysis on deodorizing effects by measuring the concentration changes of ammonia captured inside the chamber and injected into the chamber, with a lapse of time. thermo-hygrostat at a temperature of 25 during the experiment. After periods of time, the ammonia concentration inside the chamber was measured by using the detector tube and the gas collector. The difference between the concentration of ammonia produced and the concentration of ammonia measured at the maximum deodorization ability is defined as the maximum deodorization quantity. The ammonia gas was measured at an interval of every 12 hours until no change in the ammonia concentration inside the chamber was observed, which was defined as the maximum ammonia deodorization quantity. Table 5: Characteristics of ammonia detector tube Scope of Measurement ppm Measurement Time 30s Measurement limit value 0.5ppm Change of color Purple Yellow Response theory 3NH 3 + H 3PO 4 (NH 4) 3PO 4 Maximum Ammonia Deodorization Quantity (ppm) = The concentration of ammonia generated-the concentration of ammonia measured at the maximum deodorization ability Table 5 shows the characteristics of ammonia detector tube. If the air sample inside the chamber is sucked into the vacuum gas collector, the filler changes its color due to the chemical reaction of the ammonia contained in the air sample with a detecting reagent. The concentration is measured by the length of the discolored layer formed during the suction of an air sample by reading gradations printed on the detector tube. Figure 2: Schematic Diagram for Ammonia Absorption Specimens were exposed to ammonia for periods of 1, 3, 6, or 24 hours. The concentration of the ammonia emission source inside the chamber was kept at 12ppm. The boric acid solution collected during this study was measured at the wavelength of 640nm using the spectrophotometer in accordance with the indophenol method. NH 3 = W/Vo Where W= μg NH 3 from standard curve. Vo = Volume of air sample in m3 at 25 Vo = A 273/(273+T) P/760 Where A = MFC volume air P = atmospheric pressure at sampling point T = temperature, at sampling point. Evaluation of maximum ammonia deodorizing ability The maximum ammonia deodorizing ability of each specimen prepared for this study was measured. For the test, a comparative analysis was carried out in accordance with KS standards (KS I 2218, Detector Tube Type Gas Measuring Instruments). In this study, we placed specimens together with the ammonia emission source, which was prepared with ammonium sulfate and sodium hydroxide, inside a 20L chamber, and then sealed it. The chamber was kept in a sealed condition inside a RESULTS & DISCUSSION Analysis of material characteristics Analysis of microstructure Generally, pores account for half of the volume of yellow loess, and have a special structure like a honey comb, which allows for high air permeability and enables an easy absorption of pollutants. In addition, it is known that as yellow loess contains a countless number of pores like sponge, it can absorb and store far infra-red ray in large quantities. In contrast, the cement mortar has a smooth surface, which contains almost no pores [11]. Figures 3 show the respective SEM image of the flat and elevated surfaces of Hanji wallpaper. Hanji wallpaper has an entangled structure of long and thin fibers of mulberry tree, which allows for many pores between them. In regard to the volume of pores observed in the SEM images, Hanji wallpaper has the greatest number of pores. It is widely known that the moisture controlling ability and the pollutant absorbing ability are proportional to the volume of pores. 8209

4 countless number of pores between fibers of mulberry tree and displayed the largest pore volume among all finishing materials used for this study, it allowed for an easy penetration of moisture, which were then absorbed into pores. All in all, the Hanji wallpaper itself has an outstanding moisture absorption ability. Over time, the absorption quantity gradually decreased. The maximum absorption quantity was observed on the 13rd day, which was later than the ordinary Yellow loess specimens, whose maximum absorption quantity was recorded on the 10th day. Figure 3: SEM image of specimen Functionality test of yellow loess powder Test of moisture controlling ability To analyze the moisture controlling ability of the ordinary yellow loess specimens and the loess + plastering material composite specimens, the specimens in the absolute dry condition were exposed to moisture at a RH of 98% in the thermal-hygrostat, and their mass continued to be measured until they reached the point of a constant weight. The results of mass measurement are as follows. Ammonia deodorizing ability by exposure hours As shown in Figure 5, the graph, which shows the ammonia deodorizing ability of the Yellow loess + Hanji wallpaper composite specimens by exposure hours, demonstrates that all these specimens with varying degrees of thickness showed an increasing quantity of deodorization, if they were exposed to ammonia gas for longer hours, and that the Yellow loess block specimen indicated the largest ammonia deodorization quantity. When they were exposed for 12 hours, the ammonia deodorization quantity of the cement mortar specimen finished with Hanji wallpaper was about 2 times larger than that of the cement mortar specimen without any finishing. The Yellow loess block specimen and the Yellow loess plastering specimen displayed similar quantities of deodorization compared to the ordinary Yellow loess specimens. According to the results of the microstructure analysis using the SEM, the Hanji wallpaper had an entangled structure of long and thin fibers of mulberry tree, between which many pores were observed. It was presumed that this was the result of ammonia deodorization through these pores. Figure 4: Moisture controlling abilities of the Yellow loess + Hanji wallpaper composite specimens As shown in Figure 4, the evaluation results of the moisture controlling ability of the Yellow loess + Hanji wallpaper composite specimens showed the greatest moisture absorption ability even in the early stage of moisture absorption process among the specimens using any types of wall papers. Also, all Yellow loess + Hanji wallpaper composite specimens of varying levels of thickness displayed a continuous increase in terms of moisture absorption quantities from the early stage of absorption process until they reached the maximum absorption ability. The results of the microstructure analysis using the SEM showed that because the Hanji wallpaper had a Figure 5: Ammonia deodorizing abilities of the Yellow loess + Hanji wallpaper composite specimens by exposure hours The deodorization quantities of the ordinary yellow loess specimens after 6 hours of exposure to ammonia gas showed similar deodorization levels as those after 12 hours of exposure. After 12 hours of exposure, they removed almost all ammonia gas, equivalent to approximately 97%. It is known that the deodorization ability is proportional to the surface area size and the pore mass. The results of the pore property analysis demonstrated that yellow loess powder had a larger 8210

5 surface area than cement, and that the pore volume of yellow loess powder was about 20 times greater than cement, which means that the yellow loess specimens have a better deodorizing ability than cement mortar specimens [11]. In addition, as the yellow loess has a honey comb-looking special structure and more than half of the volume is comprised of pores, it can easily absorb pollutants [12]. The deodorization quantity of the yellow loess specimens showed three times larger than those of the cement mortar specimens. The yellow loess plastering + Hanji specimens showed a similar deodorization level as the yellow loess block + Hanji specimen, and it was presumed that even the 1cm thick yellow loess plastering + Hanji showed similar deodorization ability as the yellow loess block + Hanji specimen. Evaluation of maximum ammonia deodorization ability As shown Figure 6, the graph, which shows the maximum deodorization quantity of the ordinary yellow loess + Hanji specimen, demonstrates that all these specimens with varying degrees of thickness showed an increasing quantity of deodorization, if they were exposed to ammonia gas for longer hours, and that the deodorization quantity in case of 36 hours was similar to that after 48 hours of exposure. If an adsorbate or absorbent is exposed at a certain temperature for long hours, the moisture absorption/desorption does not occur any more. Likewise, it is widely known that if the external adsorbate concentration forms a certain relationship with the absorbed adsorbent concentration, it can reach the adsorption equilibrium. In case of 12 hours of exposure, the deodorization quantity could vary in spite of the same hours of exposure as shown in Figure 6, which demonstrates that the deodorization quantity could change depending on the external concentration, due to absorption equilibrium. Figure 6: Maximum ammonia deodorizing ability of the specimens As shown Figure 6, the graph, which shows the maximum deodorization quantity of the Yellow loess + Hanji wallpaper composite specimens, demonstrates that all these specimens with varying degrees of thickness showed an increasing quantity of deodorization. The maximum deodorization quantities of the Yellow loess + Hanji wallpaper composite specimens were measured as follows: Mo-H 118ppm, Lo-H 995ppm, Pl1-H 994ppm, Pl2-H 993ppm, and Pl3-H 996ppm. The Yellow loess + Hanji wallpaper composite specimens shower similar quantities of deodorization as the ordinary Yellow loess specimens. CONCLUSION This study tried to identify the minimum thickness of yellow loess plastering required to recreate the same effects as the indoor space of the Korean traditional Han-ok, analyzed the basic property of yellow loess by conducting experiments with finishing material Hanji to determine the optimal plastering thickness and raw material, as part of an effort to overcome the shortcomings of yellow loess such as staining and chipping off, and assessed the functionality of yellow loess specimens such as the moisture controlling ability and harmful substance deodorization ability. After that, we reached the conclusions as follows; 1) Hanji wallpaper has an entangled structure of long and thin fibers of mulberry tree, which allows for many pores between them. And Hanji wallpaper has the greatest number of pores. 2) According to the results of the moisture controlling ability evaluation of the ordinary yellow loess + Hanji wall paper specimen, the moisture controlling ability increased with a surge in the thickness of yellow loess plastering, and even the 1cm-thick yellow loess plastering has a higher moisture controlling ability than the cement mortar. The specimen with 3cm-thick yellow loess plastering + Hanji on the cement mortar showed similar moisture absorption ability as the yellow loess block + Hanji specimen. 3) The ammonia deodorizing ability evaluation of the yellow loess + Hanji specimen, all types of specimens showed an increasing quantity of deodorization, as they were exposed for longer hours. The yellow loess block + Hanji specimen and the yellow loess plastering + Hanji specimen showed larger quantities of deodorization than the cement mortar specimen, and the yellow loess plastering + Hanji specimen showed a similar quantity of deodorization as the yellow loess block + Hanji specimen. 4) According to the results of the ammonia deodorizing ability evaluation of the yellow loess + Hanji specimens, all types of specimens showed an increasing quantity of deodorization, as they were exposed for longer hours. ACKNOWLEDGEMENTS This research was supported by a grant (14AUDP-B ) from infrastructure and transportation technology promotion research Program funded by Ministry of Land, Infrastructure and Transport of Korean government. 8211

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