Plaster Finish Research Articles

Decoding of lime-based binder materials of ancient vernacular Chettinad constructions in Southern India through microanalytical characterization

Vernacular Chettinad lime binder is widely popular in Southern India because of its quality in terms of durability over centuries and the fine glossy finishes attainable. However, its manufacturing technique concerning raw materials, the application process, and resultant characteristics are not explored or documented. The present study attempts to explore the mix compositions and application strategies of Chettinad lime plaster and mortar by characterizing samples collected from two ancient structures approximately 100 years old and in intact condition. Like any Chettinad constructions, the plaster in both buildings constitutes a base coat (coarser as observed) and a superior smooth glossy appearance finishing layer. The plaster samples collected from various locations from the two sites were thoroughly characterized for their physicochemical properties, microstructural characteristics, surface properties, mineralogical compositions, porosity, and pore size distribution. Analyses of the plaster samples suggest that the air lime and locally available, river-based siliceous aggregates were utilized as binder and aggregate, respectively, in ratios ranging from 1:1.51 and 1:2.57 in each of the buildings studied and correlated the ratio to their durability performance as well. Shell lime and organics such as curd and egg white were utilized to obtain the glossy plaster finish. The art of manufacturing and application of such a durable indigenous binder system is lost, not continued, and undocumented. The present study would act as (i) documentation that aids the continuation of the technique of the traditional binder production, as well as (ii) decoding the compositional differences of the plaster and mortar at various locations/applications, which would help in properly maintaining and restoring degraded portions of building structures by reproducing similar and compatible material.

АНАЛІЗ ПРОТИПОЖЕЖНИХ ЗАХОДІВ У КОНСТРУКЦІЯХ ЗОВНІШНІХ СТІН ІЗ ФАСАДНОЮ ТЕПЛОІЗОЛЯЦІЄЮ ТА ОПОРЯДЖЕННЯМ ШТУКАТУРКОЮ

Метою роботи є аналіз протипожежних заходів у конструкціях зовнішніх стін із фасадною теплоізоляцією та опорядженням штукатуркою, а також аналіз особливостей їх облаштування, враховуючи досвід інших країн. Розглянуто та проаналізовано види, конструктивні особливості, призначення та функції протипожежних поясів та обрамлення віконних (дверних) прорізів, виконаних з негорючих матеріалів, які влаштовуються в конструкціях зовнішніх стін із фасадною теплоізоляцією та опорядженням штукатуркою. Наголошено на значну роль протипожежних поясів та обрамлення віконних (дверних) прорізів із негорючих плит з мінеральної вати у забезпеченні пожежної безпеки будівельних об’єктів. Зроблено висновки про те, що в Україні на національному рівні в нормативних документах процедура облаштування протипожежних поясів та обрамлення навколо віконних та дверних прорізів недостатньо технічно описана (розкрита), що призводить до випадків неправильного трактування цих вимог або взагалі їх нехтування.

Out-of-plane Strength of Existing Two-way Spanning Solid and Cavity Unreinforced Masonry Walls

An in-situ unreinforced masonry (URM) wall testing programme was conducted to study the effects of as-built wall boundary conditions on its out-of-plane strength. In total, eight pressure-controlled quasi-static airbag tests were done on 4 double-leaf cavity walls and 4 single-leaf solid walls, followed by relevant material testing. The walls were located in two 1960s URM properties in Adelaide, South Australia and had in-situ boundary conditions and construction details. Several walls included door openings at one edge and/or connected to flexible ceilings at top. Other as-built details included plaster finish on some of the internal walls and on the inner leaf of some of the external cavity walls. Additionally, the cavity walls had as-built wall ties that were damaged during construction and had irregular spacing. The main contributions of this study are to highlight the effects of these in-situ details, to make a comparison between strength predictions using an energy-based, virtual work method and an equilibrium-based method, and to improve the virtual work method for evaluation of the walls that have plaster finish. The calculations indicate that the improved virtual work method can be used to obtain a safe, lower bound, estimate of the wall strength.

Thermal performance of a selection of insulation materials suitable for historic buildings

Improvement in the thermal performance of the historic building stock has the potential to reduce building operational energy and its associated negative impact on the environment. Currently, there is a lack of knowledge on the performance of traditional solid walls and the impact of internal insulation on their hygrothermal behaviour.This paper investigates the in-situ thermal performance of seven internal insulation options, on a historic brick wall, using heat flux sensors (U-value measurement), thermal imaging survey and internal wall temperature. The insulations include thermal paint, aerogel, cork lime, hemp lime, calcium silicate board, timber fibre board and PIR board. Their performance is compared to a traditional lime plaster finish. Additionally, their density and specific heat capacity is measured in the laboratory.The brick wall with lime plaster (c.840 mm) has a higher U-value of 1.32 W/m2K than expected. All the internal insulations were found to reduce the U-value of the wall (between 34 and 61%) with the exception of a thermal paint which had no effect. The thermal imaging survey corroborated the U-value results, and insulations with low wall U-values also had high wall surface temperatures. Internal wall temperatures showed a similar trend; a reduced temperature at the wall/insulation interface for low thermal conductivity insulations. Lastly, the in-situ insulations underperformed when compared to their manufacturer's specified properties (wall U-value higher by 13–25% with the exception of cork lime). This is attributed to real in-situ environments compared to ideal testing laboratory conditions.

Experimental research on temperature and humidity control performance of hwang-toh finishing

This research analysed the effect of the ecological material yellow soil (hwang-toh) on indoor environments. To accomplish this, two full-scale mock-ups were constructed: one with PVC-foamed wallpaper, which is generally used for indoor finishing, and the other with hwang-toh, which is an ecological material for wall finishing. Comparison and performance evaluations were conducted, and the effects of hwang-toh finishing on an indoor environment were verified. Through this research, it was confirmed that a hwang-toh plaster finish is effective in maintaining the comfort humidity of an indoor environment.

Study on the Temperature and Humidity Control Performance of Hwang-Toh Finish

This research tried to analyze the effects of ecological materials on indoor environments. For this purpose, two full scale mock-ups were constructed: one with silk wall paper, which is generally used for indoor finishing and the other with hwang-toh (yellow soil), which is the preferred material for wall finishing. Comparison and performance evaluations were conducted, and the effects of hwang-toh finishing on a humid indoor environment were verified. Through this research, it was verified that a hwang-toh plaster finish is effective in maintaining the comfort of an indoor environment

Strength of carbon fiber reinforced polymers bonded to concrete and masonry

Fiber reinforced polymers (FRPs) have gained popularity in upgrades of reinforced concrete structural elements within the last decade because of their ease of application and high strength-to-weight ratio. In the design of an effective retrofitting solution using FRP systems, the anchorage capacity has an important role. This study presents the results of 57 double shear push-out tests conducted to determine the strength of carbon fiber reinforced polymers (CFRPs) bonded to concrete prisms and hollow clay tiles that are finished with and without plaster. In the experimental program, different types of anchorage methods were tested in a double shear push-out test setup. It was observed that presence of a plaster finish adversely affects the strength of CFRPs bonded to concrete or masonry. Furthermore, it was found that strength of CFRPs bonded to hollow clay tiles are significantly lower than CFRPs bonded to concrete. The proposed embedded anchors acting as shear connector were found to significantly improve the ultimate strength of surface bonded CFRPs both in the presence and absence of plaster finishing. A simple and effective strength model, calibrated using the experimental results, is verified for FRP anchors based on the existing analytical models and experimental observations from this and other studies reported in the literature.

わが国戦前期の都市独立住宅における外部意匠の変容過程に関する一考察 : 「あめりか屋」の住宅作品の外部意匠を中心に

We analyzed the exterior design of 500 houses designed by Amerikaya housing company that contributed to a development of free-standing urban housing, appeared in the architectural magazines and female magazines in the time period from 1909 to 1943. Analysis points are: exterior wall (finish), roof (shape, material, incline) and window (shape, grille) of the entrance facade showed in the photographs and drawings in the magazines. Analyzing the exterior design allowed us to make the following conclusion. 1) In Meiji and Taisho era, there were three types of finish. In particular, 'wood siding on the first floor and plaster wall on the second floor' 'steep gabled roof' 'square grill in the window' were typical. 2) In early Showa era, particularly after 1932, 'Plaster finish' 'Gently inclined gabled and hipped roof with Spanish tile' were typical. This shift from the former (1909 to 1925) to the latter (1922 to 1940) matched with the styles from Bungalow to Spanish. Both styles were brought from the United States. This study clarified strong influence of American housing on the development of Western style modern urban detached houses in Japan.

1923年関東地震による旧東京市内での各種構造物の被害の震度 : "土蔵の話"は本当か?

A famous result for the damage in Tokyo Metropolis during the Kanto earthquake was that the damage rate of dozo (Japanese traditional timber storehouse coated with clay and plaster finish) is larger in the Yamanote terrace formed by diluvial deposit than that in the Shitamachi low-land by alluvial deposit, while the damage rate of wooden houses, which determined seismic intensity, was smaller in the Yamanote terrace than that in the Shitamach lowland. We re-examined the original data of dozo on the Kanto earthquake and compared with the damage data from the 1948 Fukui earthquake and the 1855 Ansei-Edo earthquake. It can be found that the original data was strongly contaminated by the damage due to fires during the Kanto earthquake, and that the result of dozo was not trusted. The damages of RC buildings and brick buildings which had almost the same natural period as dozo, were also re-examined. We could correlate weakly the damage rate of them with seismic intensity determined from the damage rate of wooden houses, which was larger on the alluvial deposit than on the diluvial deposit.

Scagliola: Restoration of an Antique Plaster Finish in the Portland City Hall, Oregon

Scagliola: Restoration of an Antique Plaster Finish in the Portland City Hall, Oregon