Browsing by Author "Halwatura, RU"

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item: Conference-Full-text
Amplification of comfort and the air quality with green roof in cities
(2013-12-06) Wijerathne, SN; Halwatura, RU
Since the last few decades the world population has been increasing in a faster rate. With the increasing population, the needs of the people have also increased. Because of that more people have lean towards to move to the cities in search of facilities. The demand for dwellings in the cities has increased. To accommodate this demand, more buildings have been constructed, changing the previous arrangement of the cities. The cities have turned into a compacted space with less vegetation and greenery. Yet again the pervious lands in the urban space have changed to impervious surfaces making the urban climate to be changed peculiarly in terms of temperature and air quality. The more the urban space has become industrialized, the more the air has been contaminated. There are other environmental issues together with the changes for the cities. Due to the increment of artificial surfaces the temperatures of the cities have been increased than the country side allowing the heat island effect to take place making the energy demands of the cities to be high. For these climatic problems the researchers have identified green roofs as a sustainable solution. This research mainly focuses on augmentation of air quality and on reduction of heat island effect, with the replacement of existing flat slabs in the Colombo city in Sri Lanka, with green roofs. A well compacted city area was chosen in the Colombo district. The measurements were taken in terms of temperature, humidity and CO2 in the chosen city. Different special places were chosen for the measurements. The obtained measurements are observed for the identification of the best remedy. With that the expected increment of air quality and expected reduction of the temperatures are modeled with the replacement of existing flat slabs in the area with green roofs. From the results it’s evident that the green roofs can play a major role in enhancing air quality and reducing heat island effect making people to live in cities comfortably and healthily.
item: Thesis-Full-text
Cost monitoring and controlling practices of construction companies in Sri Lanka
(2014-05-30) Weerasinghe, SB; Halwatura, RU
The wealth of any nation is gauged by its performance in infrastructure provision through its construction industry. The construction industry is large, volatile, and requires tremendous capital outlays (Kaliba, Mundia & Kanyuka, 2008). Cost is a comprehensive index, which is not only closely related to the efficiency and competitiveness of an enterprise, but also reflects the superiority and inferiority of its management in various aspects. Cost control is the main means of reducing the cost of products and it serves as the precondition for the enhancement of estimation and economic returns of the business. Cost monitoring concepts have been in the international construction companies for many years. Hence, it needs to analyze the Sri Lankan context of cost monitoring in construction companies. The main objective of this research work is to discover the current cost monitoring practices in Sri Lankan construction companies, find out the drawbacks of existing CMSs, professional’s adaptation to the ICMSs and other affective characteristics related to the implementation of an automated CMS and to give some recommendation to implement an enhanced Project Management System in construction firms, in which cost management, planning and control can be gradually integrated, in order to overcome the existing limitations of the current cost monitoring systems. This research is based on the literature review and the data collected through questionnaire surveys and interviews among 57 professionals in the construction companies in Sri Lanka. With the findings of this research, it is expected to guide construction professionals towards enhancing the current cost monitoring systems in order to become more proactive, and be able to deal with the dynamic, uncertain and complex construction environment that exists in most of the construction projects in Sri Lanka. Key words: Cost, Cost Monitoring Systems, Projects, Integrated Cost Monitoring Systems (ICMS), Performance Indicators, Construction Industry.
item: Thesis-Full-text
Developing a natural acoustic barrier for urban areas
Senanayake, MAD; Halwatura, RU
Increasing noise pollution has severally effected the urban areas where noise generated by traffic is considered as the major noise polluter. As a solution to the noise problem using noise barriers is an approach proven to be effective but due to land scarcity and social needs in urban areas applying noise barrier solution is challenging. Using a natural barrier as a noise barrier is a promising approach. Natural barriers are large or small closely grown tree belts, vegetation walls, natural stone structures, tree fences etc. Natural barriers, have emerged as the new trend to address problems in urban areas and has developed into vertical gardening, green roofs and hybrid natural barriers presently. The use of natural barriers as a solution is highly dependent on the human perception. The research was carried out to identify the human perception and human acceptance of natural barriers in Sri Lankan context and find out the level of acoustic disturbance people are facing. Focusing urban and suburb areas a quantitative approach was adopted via a questionnaire survey and actual sound measurements were taken in the western province of Sri Lanka. Secondly field testing was carried out to evaluate the performance of existing natural barriers to identify their acoustic performance. Closely grown tree belts which assumes a cuboid shape were used as test barriers. Multiple Linear Regression (MLR) models Artificial Neural Network (ANN) models were used to evaluate the performance of natural barriers. Cuboid shape natural barrier with 85% of green cover or more and overall height closer to 2 meters or more has proven to be an effective acoustic barrier for urban areas.
item: Thesis-Full-text
Developing a roof slab insulation system for tropical climatic conditions
Nandapala, K; Halwatura, RU
Global Warming is proven to be one of the biggest issues that the current world is facing. Greenhouse gas emission due to the extensive energy usage has been identified as the primary cause for that. Hence, the world is on its path to investigate ways and means of reducing energy consumption in the world. On the other hand, due to the rapid urbanisation took place in recent history, land prices have escalated significantly. Hence, flat roof slabs become popular day-by-day due to the possibility of land recovery by that. Further, it has many additional advantages like cyclonic resistance, the possibility of future vertical extension and the possibility of utilising as an extra working space. However, a serious matter of concern is its thermal discomfort, for which air-conditioning the corresponding spaces is the most common remedy used. However, it has led to extensive use of energy, increasing the operational cost of the buildings and contributing to global warming, which is the issue that the world is attempting to mitigate. Hence, the current trend is to go for passive techniques. In this process, insulating roof slabs has been identified as a better passive way to make buildings thermally comfortable. In this study, several existing roof slab insulation systems and their performances were investigated, and the most efficient system for tropical climates was identified. Since that system had an issue in durability as it had poor drainage arrangement, an optimised system with a structural arrangement of discontinuous strips was found out by computer simulations. A physical model developed to verify the results showed that the newly developed system could withstand a point load of 4MT at its most critical locations. A comparison of thermal performance between the new system and the existing system was carried out by small-scale model testing. It resulted in finding that the newly designed system performs better than the most recent and efficient existing insulation system. An actual scale model testing was carried out to check its performance under real conditions. The results suggested that this newly developed system performs well in thermal aspects under actual conditions, and performs better than even a calicut tiled roof with a timber ceiling. Results suggested that this system can produce a peak cooling load reduction of about 20%. The performance of an air gap as an insulator was checked in the process of trying to replace the insulation material and found out that air gap is marginally less effective than polystyrene. Further, it was proven that the thickness of the air gap does not have a significant effect on the thermal performance. Further, a confined air gap with bamboo strips was also proven to have a similar thermal performance. An added vegetation layer on these systems further enhanced the thermal conditions of the building. A life cycle cost analysis suggested that the overlaid vegetation performs slightly better than the cases without vegetation in economic aspects. But the life cycle costing values lie in the same order, proving that all the systems considered are almost equally effective in terms of economic performance. However, due to the advantages like local and natural availability, bamboo, as an insulation material, is very favourable to be used in local context.
item: Conference-Abstract
Developing a structurally sound and durable roof slab insulation system for tropical climates
Nandapala, K; Halwatura, RU
Flat roof slabs are gaining its popularity day by day due to its advantages like cyclonic resistance, possibility for future expansion and the possibility of using them as additional working space. However, the major issue associated with roof slabs is thermal discomfort, for which, active cooling in the forms of fans and air-conditioners is the most common remedy used. This has led to extensive use of energy, increasing the operational cost of the buildings and, in the macro scale, contributing to global warming as well. Hence, the current trend is to go for passive techniques. Insulating roof slabs is identified as a better passive way to address the stated issues. In this study, several existing roof slab insulation techniques were discussed and their benefits and drawbacks were identified. While ensuring the same thermal and structural capacity of the insulation system, a new system was developed to address the drawbacks of existing systems. Computer based modelling were used to optimize the system and the small scale model testing was used to validate the results obtained by the computer simulations. Finally, a new insulation system was developed with enhanced thermal performance, structural capacity and the durability.
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Ecological design considerations in high-rise buildings with references to C02 levels
Halwatura, RU; Silva, GHE; Mahanama, HAD; Jayamanna, PMS; Jayaweera, AGTN
Rapid development coupled with urbanization has been identified as the main cause of environmental and social imbalances. This will lead to the increment of population as well as the pollutants in cities. This scenario results in limited space, there-by giving more room to high-rise buildings, which lack proper ecological design considerations. An urban area with buildings arranged densely will result in not just poor ventilation but also a strong heat island effect. Less vegetative urban areas do not have a proper mechanism to absorb the green-house gas emissions, which are increasing at an alarming rate. In a high-rise building, this effect can differ with location and also with the elevation. An in-depth analysis of Carbon Dioxide (C02) concentrations, Relative Humidity (RH) and temperature can be used to evaluate indoor air quality, which should be acceptable in terms of both health and comfort of people. A densely populated urban area located along the Galle road in the City of Colombo was chosen for the research to analyze the effect of the sea-breeze on the variation of C02 level, RH and temperature. They were obtained in each floor of selected high-rise buildings on either side (sea-side and land-side) of Galle road. Analysis of data provides evidence that the dispersion of C02 and temperature is uniform and considerably low in sea-side buildings throughout the day, where as in land side, the variation is significant. However, the variation of humidity is significant in sea-side buildings. Even though both categories of buildings experience the same heavy traffic condition of the main road data provide evidence that sea-side buildings were successful in maintaining a better indoor air quality than the land-side buildings. That implies a better indoor air quality can be achieved in properly ventilated buildings. Therefore, it concludes that ecological design consideration plays an important role in making the urban cities sustainable over a long period.
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Economical sustainability of vertical greeneries in tropical climate
(2023) Jayakody, GDC; Weerasinghe, KGNH; Jayasinghe, GY; Halwatura, RU
Vertical greening is recognized as a fascinating integration in enhancing urban environmental quality and living standards. A research series was initiated with the aim of implementing a Vertical Greening System (VGS) to achieve the maximum benefit in terms of thermal performance in Tropical Sri Lankan context. However, it is unknown if vertical greeneries are economically sustainable. The current research vacuum should be filled by assessing the economic benefit of various vertical greenery systems. This study assesses the economic value of direct green façade (DGF), indirect green façade (IGF), and living wall system (LWS) by considering installation and maintenance costs and energy-saving benefits during their life cycle, through a cost-benefit analysis (CBA). CBA is computed under three distinct circumstances: worst, middle, and best. Net Present Value (NPV), Internal Rate of Return (IRR), Payback Period (PBP), and Benefit-Cost Ratio (BCR) are the four indicators used to calculate CBA. According to the study, DGF have positive NPVs for all scenarios and have acceptable IRR and BCR values with 6 years payback period. With best and middle scenarios, acceptable NPV, IRR and BCR values with 6–7 year payback period. Over three situations, LWS exhibits negative NPVs and indefinable IRR values. From An economic point of view, DGF and IGF are economically viable and living wall systems are not viable.
item: Conference-Full-text
Effect of passive techniques in old buildings in Sri Lanka
(2013-12-06) Tharanga, KC; Mologoda, TN; Rathnayake, RNPN; Halwatura, RU
Sri Lankan old buildings are having better indoor comfort relative to the new and remolded buildings in the world .The main objective is to identify the effective passive techniques and to identify the effective usage. This paper describes the specific passive techniques in Old buildings in Sri Lanka and provides a life cycle cost analysis at the end of research project. Sri Lankan old buildings have thicker wall and special walling and roofing materials. Several properties from those properties have been analyzed deeply with considering the environmental background. Inside thermal comfortable of old buildings must be checked to apply those techniques to new buildings. This paper shows the inside conditions of analyzed buildings as numerical values after taking temperature and humidity measurements of the building in day time. This research paper presents the DEROB temperature results with adding old and new building properties to typical building and then it compares the results obtained from computer modeling. Life cycle cost analysis is carried out to compare the results in economical manner for each selected passive techniques. It is used to identify the most effective passive techniques. Final analyzing has been done with numerical values of temperature and cost for construction and maintaining. Some restrains are occurred when adopting old passive techniques to new buildings. This research has been discussed the possibilities and limitations when those properties are adding to new buildings, at the end of the research project.
item: Conference-Full-text
An Empirical Study Of The Impact Of User Training And Attitude Towards ERP Implementation In Selected Companies In Sri Lanka
Kumara, AS; Gunawardana, KD; Halwatura, RU
Implementation of an Enterprise Resource Planning (ERP) is a radical change in an organization. Some of the staff are willing to accept new challenges whereas others are not. Therefore, there is a gap between attitudes of the staff who would involve with the ERP systems and desired objectives of the system. Conducting different types of user training programs can improve communication with employees. It makes them to change their attitudes. This study focused on user attitudes and the effectiveness of training towards the ERP implementation in Sri Lankan Companies. The data collection was done through a series of structured interviews and a questionnaire from the five top recently ERP implemented companies in Sri Lanka. One-way ANOVA result shows the users’ attitudes vary from different age groups and the education level of the employees. Further, findings reveal that attitudes have a positive impact depending on their income level and the number of years that they worked for the company. Based on the analysis it can be conclude that the way of training should change.
item: Conference-Full-text
An Empirical Study of the Impact of User Training and Attitude Towards ERP Implementation in selected Companies in Sri Lanka
Kumara, AS; Gunawardana, KD; Halwatura, RU
Implementation of an Enterprise Resource Planning (ERP) is a radical change in an organization. Some of the staff are willing to accept new challenges whereas others are not. Therefore, there is a gap between attitudes of the staff who would involve with the ERP systems and desired objectives of the system. Conducting different types of user training programs can improve communication with employees. It makes them to change their attitudes. This study focused on user attitudes and the effectiveness of training towards the ERP implementation in Sri Lankan Companies. The data collection was done through a series of structured interviews and a questionnaire from the five top recently ERP implemented companies in Sri Lanka. One-way ANOVA result shows the users’ attitudes vary from different age groups and the education level of the employees. Further, findings reveal that attitudes have a positive impact depending on their income level and the number of years that they worked for the company. Based on the analysis it can be conclude that the way of training should change.
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Evaluation of green infrastructure effects on tropical Sri Lankan urban context as an urban heat island adaptation strategy
(Elsevier, 2018) Herath, HMPIK; Halwatura, RU; Jayasinghe, GY
Incorporation of strategic green infrastructure into urban settings has a potential to mitigate climate change, urban heat island (UHI) effect, flood risk and subsequent increase in quality of human life in general. UHI induces through low surface albedo, building geometry and absence of greenery and it deteriorates the thermal comfort and well-being of city dwellers and occupants. This study examined the implication of urban green infrastructure on enhanced microclimatic condition in tropical urban perspective while evaluating the best suitable strategy by modeling a designated site with ENVI-met microclimatic software (V4). The calibration procedure of ENVI met has been undertaken through a real ground monitoring process and the software modeling was done for selected urban setting. The model was firstly validated by reconciliation of observed in-situ measurements with simulated values. R-squared (R2) values for three different surface types such as asphalt, cement and grass were 0.91, 0.96, 0.88 for near ground (0m) and 0.78, 0.81, 0.92 for 1.5 m, respectively. The parametric studies verified that ENVI-met model can be effectively utilized to improve urban micro-scale thermal conditions in tropical Sri Lanka. The numerical simulation model of ENVI-met was used to generate micro-climatic data for the selected area of Colombo metropolitan region with six greening design scenarios such as prevailing UHI condition (T1), trees in curbsides (T2), 100% green roofing (T3), 50% green roofing (T4), 50% green walls (T5) and a combination (T6) of above mentioned green strategies (trees in curbsides+ 50% green roofs+ 50% green walls). Temperature reductions obtained from all green strategies were compared with existing UHI (T1) scenario during peak temperature in given time. The temperature reductions accomplished by T2, T3, T4, T5 and T6 green infrastructure options compared to T1 were 1.87 °C, 1.76 °C, 1.79 °C, 1.86 °C and 1.90 °C, respectively. It can be concluded that strategic design of urban greenery can effectively enhance the urban environment and outdoor thermal comfort in tropical Sri Lanka.
item: Conference-Full-text
Fly ash-based geopolymer mud concrete block
(IEEE, 2018-05) Udawattha, CD; Lakmini, AVRD; Halwatura, RU; Chathuranga, D
The high production of fly ash due to the combustion of coal causes several environmental problems such as water pollution, air pollution, etc. Therefore, the use of fly ash as a stabilizer for the construction of mud concrete will reduce these problems. The idea of building mud concrete blocks is to convert stable natural soil into an engineered block. Mixing fly ash alone did not generate a significant strength. For a loaded construction, the minimum dry compressive strength must be greater than 2N/mm2 and the wet compressive strength must be greater than 1N/mm2. This investigation is carried out to evaluate the alkaline activation of the fly ash to stabilize the soil and build geopolymer self-compacting mud concrete blocks. Alkaline activation of fly ash to build geopolymer is not a novel concept. But employing the idea in self-compacting mud concrete is new study. Initially, it was found that the optimum content of fly ash stabilized the soil. It was found that NaOH and NaCl can increase the pH content of the mixture and increase the resistance to the required level. Ultimately, heating can develop a much better mix than cement stabilized mud concrete mix.
item: Conference-Full-text
Health and safety aspects in building construction industry in Sri Lanka
(2013-11-13) Halwatura, RU; Jayatunga, TL
Construction sector in Sri Lanka has tremendously grown in the recent past and construction has developed into an important base of the national economy. However, although being healthy and safe is an important aspect of construction, it remains unsatisfactory in Sri Lankan building construction industry, which takes the foremost share in constructions. Moreover, accidents result heavy loss of time, cost and resources, which are considered as the most valuable assets in the industry. This research was carried out with the intention of identifying the causes and effects of weak health and safety practices and to recognize the areas to be strengthened in this regard. Secondary data on fatal and nonfatal accidents, which have occured in recent past, were collected to identify trends of the construction industry. Then, it was extended with a questionnaire survey among the professionals in the construction industry to identify the causes for accidents and the ways to mitigate their risk. Gross Domestic Product (GDP) of Sri Lanka clearly shows that the construction is growing at an increasing rate while the number of fatal accidents is also increasing at a higher rate than that. It clearly shows that there is lack of attention is paid on health and safety aspects with the progress of the industry. Through the questionnaire, the key areas which cause accidents and the most significant areas that have to be strengthened in the construction industry in Sri Lanka was identified.
item: Conference-Abstract
The Impact of green roofs on urban heat island effect
(2016-10-12) Wijerathne, SN; Halwatura, RU
Growth of the world urbanization has been extensively accelerated since past few decades. With the increasing urbanization, the land with permeable layers and moist have been altered. As a result, urban heat island phenomenon has taken place, making the temperature in the cities to be higher than the country sides. Heat island effect in cities is mainly because of non natural heat absorbing materials use in buildings and other man made structures. Natural greenery in the cities was replaced by concrete yards and most of the cities urbanizing with more and more concrete. Since there is no space to grow, adding greenery to cities is also an issue. Having greenery over the roof or planting on roofs are now becoming popular in many countries. Green roofs play a major role as a sustainable solution to minimize the heat island effect. This paper discusses about the effects on the surrounding temperatures, if the existing flat roofs in the Colombo city, the capital of Sri Lanka, are replaced with green roofs. The reduction in the temperature in the atmosphere was calculated using actual measurements on small scale models and computer simulation. These findings were coupled with the energy balance of the city. From the results obtained, it can be clearly shown that there’s a significant reduction in the temperatures, in the city when compared to the prevailing condition. The forecasted condition proves that the foreseeable problem of urban heat island effect with the future developments can be drastically reduced with the introduction of green roofs
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Influence of grain distribution on orientation of saw cuts: Reference to heritage structures
(Elsevier, 2019) Mendis, MS; Halwatura, RU; Somadeva, DRK; Jayasinghe, RA; Gunawardana, M
Longitudinal arrangement of wood fibers are known as timber grains. It is one of the most important physical aspects of timber in applications. The properties differ along the grain and against the grain. Straight grains run parallel to the longitudinal axis of the wood. Meanwhile the cross grain deviates from the longitudinal axis as spiral and diagonal grains. This orientation has a high influence on the timber and affects physical properties during application. In order to study this, a detailed analysis was performed on Ambalam structures, a cherished heritage structure originated from the vernacular architecture in Sri Lanka. These structures are existing living proofs of vibrant construction materials with an exposed environment for more than 50 years. Badulla Ambalama,Padivitiya Ambalama, Panavitiya Ambalama, Karagahagedra Ambalama, Giruwa Ambalama and Rukula Ambalama were selected as case studies. The growth ring distribution of the exposed surfaces of the structural components were mapped using AutoCAD software. The results of overlapping and mapping the growth ring distribution of the specific timber helps to generate clues on size of the tree and sawing pattern of the wood log. The generated growth ring map revealed the sensitivity and the adequate knowledge in material manipulation utilized for specific structural components with respect to the load distribution. The Ambalam heritage structures have enlighten timber as an acceptable construction material with a respectable service life for tropical countries.
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Influence of insulated roof slabs on air conditioned spaces in tropical climatic conditions: A life cycle cost approach
Halwatura, RU; Jayasinghe, MTR
The recent energy crisis and the environment impacts of building industry have led to the active promotion of principles of sustainable development in recent times. Minimization of energy usage is the key to improve sustainability where the actual impact is assessed on the basis of life cycle cost estimates. In this context, the performance of insulated roof slabs which can be used as an alternative to conventional light weight roofs, have been assessed in detail especially with respect to air conditioned buildings. It is shown that insulated roof slabs could have a desirable behaviour with respect to life cycle performance in addition to providing other benefits such as cyclone resistance and higher robustness to the building.
item: Conference-Full-text
Influence of straw bale construction in air conditioning in tropical climatic condition
(2013-11-12) Halwatura, RU; Chamila, JPS; Somarathna, ABVPR
Due to heavy industrialization that took place after the Industrial Revolution, per capita energy consumption in the world has risen exponentially, depleting the planet’s limited energy deposits. As a result of most the modern technologies, unfavourable conditions on the environment are created. So, there is an urgent requirement to move towards the methods, which minimize the energy demand. Electricity demand in Sri Lanka is higher than its production and the usage of Air Conditioning is increasing day by day. Therefore, straw bale was identified as a feasible substitute to be used in addressing the increasing demand for A/C due to many reasons such as low initial cost, low conductivity and durability. Hence, studying on the long term performance of straw bale construction will be highly essential. On this regard, actual measurements were taken and were used to validate the computer simulations for straw bales and other walling materials to get the A/C demands for different cases. These findings were expanded to its life cycle by adopting them to an A/C building. Comparisons were made with other common walling materials available in Sri Lanka. It was noted that the straw walls can reduce the A/C demand of a building and hence it can lead to a low life cycle cost of the structure.
item: Conference-Abstract
Investigating the adaptability of existing building energy rating systems to sri lankan residential buildings
Pathirana, SM; Halwatura, RU
Energy represents a considerably higher percentage of running cost of a building and also affects the optical and thermal comfort of the occupants. Despite the fact that the investment for buildings is higher than most of those equipment, only developed countries and few developing countries have developed their own energy ratings or certifications for buildings. Nevertheless, energy efficiency in building sector is utmost important as it accounts more than one fifth of annual energy consumption worldwide. Energy efficiency rating system can be considered as a key policy instrument that will assist government to reduce the energy consumption. Energy rating includes the direct benefits such as, energy requirement and CO2 emission reduction; increase the public awareness regarding energy issues; cost reduction for the users and improve the available data for the building. Studying the existing energy rating systems is very much important prior to the development of energy rating system for Sri Lanka. This paper examines 12 existing energy rating systems and analyses the adaptation opportunities for emerging Sri Lankan energy labelling system. The existing rating methodologies including asset and operational rating, parameters used for developing the energy rating and the comparability matrix were compared and discussed in this review.
item: Conference-Full-text
Investigation of mechanical properties of mud concrete with coconut fiber reinforcement
(IEEE, 2020-07) Galabada, H; Galabada, PD; Galkanda, H; Halwatura, RU; Weeraddana, C; Edussooriya, CUS; Abeysooriya, RP
Mud concrete was a sustainable innovation, invented to replace existing conventional construction materials with sustainable material. Mud concrete consists of soil and cement along with water. In terms of sustainable construction, cement which act as the stabilizer in mud concrete should be kept lesser as much as possible, according to its potential environmental issues. Therefore, evaluation of ability to enhance the mud concrete properties by adding some admixtures is essential. There are no of admixtures used in the construction industry with many forms, such as liquid, solid, semisolid or fiber. In most of the studies fiber was used as an admixture to improve the strength performance of construction materials. Hence, evaluate the strength performance of mud concrete with fiber is important to reduce cement in sustainability contest. Therefore, this study was investigated the effect of natural fiber length on compressive strength and strength variation with water content of mud concrete with fiber. According to the results, the highest strength was recorded with the fiber length of 60 mm and the compressive strength was decreasing with the increasing water content. The study concluded that the optimum fiber length is 60 mm and there is a negative correlation between compressive strength and water content.
item: Conference-Full-text
Investigation of possible vegetation for a natural sound barrier
(Department of Civil Engineering, University of Moratuwa, 2015-10) Wickramasekara, DUP; Halwatura, RU; Hettiarachchi, MTP
Noise pollution has been identified as the third most hazardous type of pollution in the world. Vegetation was used for experiments recently to check the effectiveness as a sound barrier. This research includes a qualitative analysis of natural vegetation fences to identify the parameters contributing to noise attenuation and its effectiveness. A-Weighted noise levels were measured for frequencies ranging 125 Hz to 16 kHz upto 9m from barrier using a sound level meter with 1:1 octave band. Same test was carried out for artificial walls to compare the effectiveness of vegetation barriers. The identified parameters contributing to noise attenuation were thickness of the barrier, leaf density (primary) and height (secondary). According to results, a vegetation barrier of considerable thickness, height and dense leaves can achieve the effect of a low height artificial barrier. Although vegetation attenuate noise, it seems to be not enough to reduce the current noise levels below the level that can be borne without annoyance.