The role of different salt solutions and their concentration ratios in salt crystallization test on the durability of the Döğer tuff (Afyonkarahisar,Turkey) used as building stones of cultural heritages

Bulletin of Engineering Geology and the Environment - Volcanic tuff is widely used in Anatolian architecture and represents building stones of cultural heritage. The present study included a...     

Changing conceptions of “mandala” in tang china: ritual and the role of images

ABSTRACT

“Changing Conceptions of ‘Mandala’ in Tang China: Ritual and the Role of Images” is concerned with the intersection of visionary experience with visual forms. The focus of the study is a Buddhist incantation, or Dhāranī, titled the Revered and Victorious Dhāranī of the Buddha's Usnīsa. This particular dhāranī was widely circulated in China during the Tang dynasty (618–907); for this reason, it may be approached as an important case study for studying the conceptualization of mandalas in China prior to their transmission to Japan in the early ninth century. Through a detailed examination of successive translations and ritual manuals associated with the Revered and Victorious Dhāranī of the Buddha's Usnīsa, different conceptions of mandalas and the roles that were played by images may be observed. This, in turn, responds to larger questions in East Asian Buddhism and studies of Buddhist art regarding the functions of painted mandalas during Buddhist rituals. Lastly, this article seeks to shed light on lesser-known aspects of esoteric Buddhist art in Asia, as the scholarship to date on Buddhist mandalas has primarily focused upon studies of Japanese and Himalayan works.     

Why assess the properties of near-surface concrete?

The deterioration of concrete structures is a major problem in many countries throughout the world. This has prompted the search for methods of predicting the service life of both existing and new structures. Current prediction methods are still in their infancy and, before they can be used with confidence, more reliable information on the properties of the concrete in these structures will be required. In this paper a range of test methods for determining the strength and transport properties and the extent of corrosion are critically reviewed. Whilst all provide useful information the ability to measure the transport properties has been shown by many researchers to give the most reliable indication of the likely durability. In spite of this it is recommended that an holistic overview is adopted as no single test is sufficiently reliable at present. Using such an approach, durability-based design criteria can be developed for concrete and the remaining life of existing structures estimated.     

Impact of physico‐chemical parameters on the microbial population and its nature in a major retting zone of Kerala

As part of an environmental abatement programme, through the application of bioremediation in the retting zones of Kerala, a microbiological survey was conducted during March 1999 in the Kadinamkulam kayal, a major retting zone in Kerala. Some selected physico‐chemical parameters were also analysed to assess the water quality in the context of retting activity. Comparatively low dissolved oxygen content coupled with high hydrogen sulphide observed at Stations 1 and 2 can be attributed to retting. Salinity distribution is of the mixohaline nature. Pseudomonas sp., E. coli and other coliform groups were found to be present in the area. Of these the most dominant was Pseudomonas sp. and hence its nature and plasmid profile were also studied. The study indicates an environmental degradation in the area, and the possibility of hotspots of pollution in the backwater biotopes in the State.     

Analysis of the stabilising effect of ribs of reinforced sprayed concrete (RRS) in the Løren road tunnel

Bulletin of Engineering Geology and the Environment - The Løren tunnel is a road tunnel at Ring road 3 in Oslo, Norway. The tunnel has a length of 915 m in rock, has two tubes with...     

Chloride penetration in concrete under marine atmospheric environment – analysis of the influencing factors

Marine atmospheric exposure conditions provide a severe environment for reinforced concrete structures, mainly due to the occurrence of chloride-induced reinforcement corrosion. This procedure was influenced by many parameters related to the concrete properties and to the environmental condition. In this paper, cubic concrete specimens with 150-mm edge, different types of cementitious material and different strengths, were arranged on a structure, which exposed them to a natural marine atmospheric environment. The purpose was to evaluate quantitatively the influence of different exposure conditions on the durability of concrete, measured in terms of chloride penetration into concrete. Both relative humidity (RH) and temperature were monitored in the experiment. The results indicated that the surface RH and temperature of the concrete were much different from that of the air. The diffusion coefficient and surface chloride concentration were time- and location-dependent, and were influenced by the RH, temperature, and the concrete strength. The results also indicate that error results would be made when using constant diffusion coefficient and surface chloride concentration with the air RH and temperature to predict long-term chloride penetration.     

Effect of freeze–thaw and thermal shock weathering on the physical and mechanical properties of an andesite stone

Natural stones are exposed to physical weathering due to freeze–thaw (F–T) and thermal shock (TS) when they are used as pavement, cladding and masonry material. In this study, the deterioration of andesite was investigated by determining the physical and mechanical properties of andesite samples after each 10 cycles of F–T and TS up to 50 cycles. It was found that the P-wave velocity, Schmidt hardness and compressive strength decrease to different extents with F–T and TS while porosity and water absorption increase with F–T cycles but decrease with TS cycles. The results showed that F–T has a more destructive effect on the studied material than TS, although abrasion loss measurements suggest that the effect on the surface of the material is greater with TS. An exponential model is proposed to predict the variation of material properties with F–T and TS cycles.     

What is the role of tensile cracks in cohesive slopes?

The traditional limit equilibrium method (LEM) is often used to search for the failure surface with a minimum safety factor of slope. In this method, the failure surface is considered as a shear surface, irrespective of its form. However, tensile cracks are frequently found at the outcrops of landslides. In this study, three sets of tests on small-scale landslides with different inclination angles were conducted. The test results demonstrated that tensile cracks could arise in the slope sliding process and the failure surface is composed of both a shear and a tensile fracture surface. Based on the test results, we used the improved LEM, and replaced the traditional shear failure surface by a tensile-shear coupling one, thus new tensile failure modes for slope stability analysis can be established. The safety factors of slope in different failure modes were compared, which show that when considering soil tensile failure and tensile strength less than a certain value (e.g. 15 kPa, 44 kPa and 55 kPa for linear, circular and logarithmic spiral failure surfaces, respectively), the safety factors of slope with three different failure surfaces are less than the one that did not consider the tensile failure. The most critical failure surfaces of the slope may be composed of shear and tensile damages because the tensile strength of the soil cannot be generally greater than its cohesion.     

Influence of test specimen on experimental characterization of timber–concrete composite joints

Load-carrying capacity of timber–concrete composite joints is usually evaluated using shear tests, which still lack specific standards. Regulations EN 26891 [1] and ASTM D 5652 [2] are usually used, both for timber joints, or EUROCODE 4 [3] for steel–concrete composite joints. Questions about test execution and arrangement of specimens are frequent and recurrent [4], [5], [6]. Steel–concrete composite structures already have a standard shear test for joints (push-out), described in Johnson and Anderson [7]. These authors also discussed the many differences in the results of shear tests because of differences in test methods before EUROCODE 4 [3] standardization.This paper presents some questions about the arrangement of test specimens for shear tests in timber–concrete joints. An experimental program was performed for this reason. The aim of the work was to compare shear test results using two different series of specimens most utilized in a review of the literature: the push-out type with concrete center and timber sides and the push-out type with timber center and concrete sides. 8.0, 10.0 and 12.5 mm diameter corrugated bars were used as connectors. Eucalyptus grandis Brazilian hardwood timber glulam was used. Two-component epoxy adhesive was used to glue the connectors into the timber. Average cylinder compressive strength of the concrete was 25 MPa (28 days old). Reinforcement was 6.0 mm diameter 500 MPa-yield-stress corrugated bars.The results showed that test specimen arrangement influenced the strength and deformation characteristics of timber–concrete composite joints. The specimen with the best shear strength was the concrete–wood–concrete type, similar to those used in steel–concrete composite structures. Since the arrangement of test specimen is an important factor in joint tests, it is recommended that further efforts be made towards standardization.     

“Plagioclase solution degree index”: a new index to evaluate the weathering degree of granite

The weathering degree of rocks has an adverse influence on their strength and deformability characteristics, which in turn influences the industrial uses of rock. The need to develop a weathering index that reveals their mechanical and engineering geological behaviors is thus pertinent to enable the building of more accurate models for forecasting geological hazards. Granite weathering in the Ma On San, Shek Kip Mei and Kwun Tong areas of Hong Kong was studied using scan electron microscope (SEM) images to observe mineral shapes for detailed identification of the weathering degree of completely decomposed granite (CDG). Plagioclase images captured from the SEM were subsequently analyzed and processed with the use of a microstructural image processing system. The results of the analyses indicate that plagioclase, though sensitive to weathering, still remains in CDG and is preserved at different weathering degrees. Hence, it provides a possibility for evaluating the weathering degree more accurately. Thus, a new index referred to as the plagioclase solution degree index is proposed to evaluate the weathering degree of granite.     

Impact of “We Media” on Public Participation in Urban Planning:A Case Study on the Urban Design of Xuanwu Avenue in Nanjing

From a stakeholder perspective, this paper discusses the positive and negative impacts of “We Media” on public participation in urban planning based on a case study on the public event related to the Urban Design of Xuanwu Avenue in Nanjing. This research draws the following conclusions. Firstly,“We Media” helps to reduce the cost of the bottom-up feedback in the public participation process as it expands information dissemination approaches, and the comprehensiveness and objectiveness of the in...     

Sand–concrete interface response: The role of surface texture and confinement conditions

Sand–concrete interface direct shear tests were used to investigate the effects of surface roughness, surface waviness, mean sand diameter and relative density on interface strength and behavior under different confinement conditions. Extreme concrete surface textures, including smooth, rough and rough–wavy textures, were reproduced. Surface plowing was assessed via image analysis, laser scanning and extended multifocal micrographs. The experimental results showed that smooth concrete surfaces exhibited high values of interfacial–to–internal friction angle ratios, ranging 88–90%, due to the angular shape of sand particles. The rough concrete surfaces generated higher interface strength than smooth concrete surfaces; however, the interface strength was still inferior to the surrounding sand strength. Surface plowing, which identified a mixed shear plane at the sand–concrete interface, was developed as particles were detached from the surface, thus inhibiting the interface friction angle from reaching the sand friction angle. Higher sand–concrete interface strength was achieved as surface waviness increased, and interface friction angles greater than the surrounding sand friction angle were reached. Under a constant normal stiffness condition, significantly high interface strength is achieved due to the increase of the current normal stress, which was directly influenced by the initial normal stress, stiffness, surface roughness, mean sand diameter and relative density; surface waviness did not have a marked effect on the normal stress variation. Based on these results, multiple regressions were proposed to estimate the sand–concrete interface strength by the interfacial–to–internal friction angle ratio and the effect of the constant normal stiffness condition.     

Modelling the phase change of salt dissolved in pore water – Equilibrium and non-equilibrium approach

Salts strongly influence the durability of porous building materials. There are two main processes, which are responsible for the damage of the materials related with salt presence in the pore system. The first one is the corrosion of steel bars triggered by chlorides. Chlorides exist in two forms: free chlorides dissolved in pore water and bound chlorides. It is believed that only free chlorides are responsible for the corrosion. Therefore it is very important to define and model properly the chloride binding isotherm and its influence on free chloride transport. The linear, Freundlich and Langmuir isotherms were tested. Another adverse phenomenon is the salt crystallisation, which is associated with the supersaturation. This phenomenon is modelled using the kinetics of salt crystallisation. The model and its numerical solution describing the salt and moisture transport including the equilibrium and non-equilibrium phase change of salt in non-isothermal condition is proposed. To model the kinetics of salt crystallisation the simple approach proposed by Espinosa et al. was utilised. The drying, cooling and warming of cement mortar sample, during which the salt phase change occurs, were simulated using the developed software. The changes of salt concentration and the amount of precipitated salt due to variation of boundary conditions are presented. The model including kinetics of salt phase change is found to be reliable.     

Effect of Metakaolin’s finesses and content in self-consolidating concrete

Self-consolidating concrete is characterized by its high deformability or its capability of filling all the spaces without external forces, maintaining the stability, without segregation or blocking. SCC needs high content of fines, which could be mineral admixtures, superplasticizer and low content of aggregates with limited maximum dimensions. Present work intends to verify the effect of the finesses and content of Metakaolin in SCC properties with different paste volumes, at fresh and hardened states. Metakaolin was used at three different finesses and at 5% and 35% of substitution to cement mass. It was found that the superplasticizer consumption increased with higher finesses and content of Metakaolin. Increasing the paste volume, less superplasticizer was necessary. Better mixtures were obtained with the paste contents of 0.45 and 0.50, by total volume, which presented good cohesion and a reduced admixture consumption. However, for the compressive strength, a reduction occurred at high paste volumes.     

Views on Three Milestones in the Construction of Beijing City

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Revisiting the role of architects in planning large-scale housing in the USSR: the birth of socialist residential districts in Tallinn,Estonia, 1957–1979

In Central and Eastern Europe and the Former Soviet Union, housing estates are often associated with inhumane architecture and unwelcoming public space, an outcome that can be attributed to strict design requirements in a rigid centralized system. Due to the uniformity of residential housing produced during socialist times, both the design process and its master – the architect – are believed to have played only minor roles in shaping townscapes. This study, situated in the large housing estates of Tallinn, Estonia, challenges these assumptions using analyses of archival material (relating to planning procedures during state socialism) and articles in specialized magazines. The study also explains – through first-hand interviews with senior architects who were key players in building socialist cities – the relations between Soviet regulations and vital elements of the city-building process, including creativity, power, and artistry. Analysis of primary source materials highlights an oversimplification of socialist modernism, which suggests more nuanced explanations for town planning outcomes. Findings suggest that regulations issued in Moscow for Union of Soviet Socialist Republic-wide planning played a less important role than previously assumed in town planning outcomes in Estonia. International modernist city planning ideals, combined with local expertise, strongly influenced town planning practice in the Soviet ‘West’.     

A Review of “Capital in the Twenty-First Century”

This article portrays basic socioeconomic information now provided by the Bureau of the Census concerning the characteristics of those who become planners and the distribution of these characteristics throughout the occupation. Focus is on the actual numbers of urban and regional planners within the United States, their sex, race, age, formal education, yearly earnings, and place of employment.     

Explaining and evaluating the quality of “light” in religious environments and its effect on spirituality

The current study aimed to investigate the quality of the interior architecture of the religious spaces regarding inducing the sense of spirituality with an emphasis on light. Thus, the authors introduced the best option by simulating the light intensity of the interior environment of the Nasir Al-Mulk Mosque, Shiraz, in software and developing a visual standard questionnaire with a statistical population including the experts. This research was a field, and survey study and computational software were used to simulate the light intensity of the interior environment of the mosque in the first part. Then, the researcher-made visual questionnaire was developed. Also, this questionnaire was sent to the experts online due to the current situations due to the Covid-19 pandemic. The statistical population was selected using the purposive sampling method from the universities of Iran, Malaysia, India, and Turkey, whose expertise was architecture, environmental psychology, and sacred arts.     

‘Clubification’ of urban public spaces? The withdrawal or the re-definition of the role of local government in the management of public spaces

This paper reports on a case study on the forms of urban public spaces governance that are emerging in the UK out of a rearrangement of governance responsibilities between local government, communities and private interests. Based on cases of public spaces in London under a variety of different governance arrangements, the paper critiques the dominant explanations of those processes, and suggests a far more complex picture in which empowerment and disempowerment of stakeholders of various types happen at the same time, along complex lines defined by geography, strength of stake and representation of that stake in a formalized governance transfer contract. As the paper suggests, the resulting ‘localization’ of governance, the devolution of governance responsibilities to those local actors with the stronger stake in them, does not intrinsically reduce the publicness dimension of public space, but it reshapes that notion towards one with a variety of ‘publicnesses’, with their own governance dynamics and positive and negative consequences.     

A Preliminary Research on the City Planning of “Yin”,Capital of the Shang Dynasty

“Yin”was the capital of Shang Dynasty.On the basis of archaeological findings,theauthor explored the planning and layout,distributions of city functions,structural patternsand so on of this capital of the China's slave society 3,000 years ago from the viewpoint ofcity planning.Through analysing the detailed layout of the imperial palaces,residentialareas,handicraft workshops and imperial tombs of the ancient capital city from the thensocial and economic background,the author believes that the city planning concept of theancient“Yin”township has far-reaching influence on the city planning of different dynas-ties in Chinese history.