Globally, 998 million tonnes of agricultural waste is produced per year and in Malaysia, 1.2 million tonnes of agricultural waste is disposed of into landfills annually. Concurrently, increasing demands of concrete leads to vary of research conducted on improving cement production methods and formulating reduction or eliminate CO2 emissions.
This paper investigated the seismic retrofitting of an existing cable-stayed bridge through the use of a seismic isolation system. The bridge is situated in a high seismic zone. During the Saguenay earthquake 1988, one of the anchorage plates of the bridge supports failed. Herein, several configurations of seismic isolation system were considered to identify an appropriate solution for the seismic retrofitting of the bridge in both the longitudinal and transverse directions. A three-dimensional model of the bridge was created, and its seismic behavior studied through nonlinear dynamic time-history analysis. The comparative performance study among the five retrofitting configurations showed that the partial seismic isolation of the bridge led to an enhancement of the seismic response of the bridge in one direction only. However, the overall seismic response of the cable-stayed bridge substantially improved in the longitudinal and transverse directions in cases where the isolation systems were utilized between the supports and the deck-tower connection of the bridge.
Addition of chemical binders such as lime and cement improves the strength and stiffness
of fine grained soils. However, the treated soils exhibit brittle stress-strain behaviour.
Inclusion of randomly oriented discrete fibers in the soil-binder mixture changes its brittle
behaviour into ductile behaviour. Most synthetic fibers, however, tend to get entangled
and cannot be easily separated from one another. Therefore, it is difficult to realize soilbinder-
fiber mixtures in which the fibers are distributed uniformly throughout the mass.
This issue has been an impediment in the utilization of the positive modification in the
behaviours of soils and soil-binder mixtures by the fibers. The present study aims to address
the limitations in using fibers as soil reinforcement. Further, it also aims to investigate
the use of synthetic mesh or net elements as an alternative type of soil reinforcement.
The paper presents the experimental study on a fine grained soil. Lime has been chosen
as the binder due to its low cost and the scarcity of fiber reinforced soil studies in which
lime has been used as a binder. The main experimental program is a series of unconfined
compression tests on samples prepared using untreated soil, soil-reinforcement mixture,
soil-lime mixture, and soil-lime-reinforcement mixture. The lime treated samples were
cured up to 120 days at laboratory temperature. The results demonstrate the combinational
effects of lime and discrete reinforcement
elements on the behaviour and mechanical
properties of the soil. The performances of
the fiber and mesh element reinforcements
have also been compared.
Radon gas has been known as one of the main factors that cause breathing complications which lead to lung cancer, second only after smoking habit. As one of the most commonly found Naturally Occurring Radioactive Materials (NORM), its contribution to background radiation is immense, and its contributors, Uranium and Thorium are widely available on Earth and have been in existence for such a long time with long half-lives. Indoor radon exposure contributed by building materials worsens the effects. The probability of inhaling radon-polluted air and being surrounded by it in any buildings is very high. This research is focused on the detection of radon emanation rate from various building materials which are commonly being used in Malaysia. Throughout this research, common building materials used in constructions in Malaysia were collected and indoor radon exposure from each material was measured individually using Tight Chamber Method coupled to a Continuous Radon Monitor, CRM 1029. It has been shown that sand brick is the biggest contributor to indoor radon compared to other samples such as sand, soil, black cement, white cement, and clay brick. From the results, materials which have high radon emanation could be reconsidered as building materials and mitigation action can be chosen, suitable to its application.
Diverting waste material from landfill sites has a big implication for the creation of new markets and has environmental benefits through offsetting the need for the extraction of raw materials. Besides, the major attention especially in construction industry is the problem to make natural resources sustainable for three to four decades in future. However, in this study finely glass powder with pozzolanic properties is found to be a partial replacement for cement and can acts as filler in the microstructure of a mortar block. Thus, a study was conducted to see the effects of various proportions of windscreen glass waste powder (WGWP) in determining the degree of water absorption on mortar incorporated with WGWP and to determine the optimum replacement to the ordinary Portland cement (OPC) with WGWP. Several compositions of WGWP (0%, 5%, 10%, 15% and 20% by cement weight) of mortar cube sample were prepared and cured at 7, 28 and 60 days to undergo a water absorption test. From this research, it shows that the use of WGWP was found to be the best features pozzolanic enough to use as a partial replacement for cement and it can reduced the pores of mortar by blocking the large voids in the hydrated cement paste through pozzolanic reaction. In the term of water absorption, the lowest reading was achieved in 15% and it can be said that 15% replacement is the optimum replacement of OPC.
The influences of climate on the retention capability of green roof have been widely discussed in existing literature. However, knowledge on how the retention capability of green roof is affected by the tropical climate is limited. This paper highlights the retention performance of the green roof situated in Kuching under hot-humid tropical climatic conditions. Using the green roof water balance modelling approach, this study simulated the hourly runoff generated from a virtual green roof from November 2012 to October 2013 based on past meteorological data. The result showed that the overall retention performance was satisfactory with a mean retention rate of 72.5% from 380 analysed rainfall events but reduced to 12.0% only for the events that potentially trigger the occurrence of flash flood. By performing the Spearman rank's correlation analysis, it was found that the rainfall depth and mean rainfall intensity, individually, had a strong negative correlation with event retention rate, suggesting that the retention rate increases with decreased rainfall depth. The expected direct relationship between retention rate and antecedent dry weather period was found to be event size dependent.
Kuala Lumpur has been undergoing rapid urbanisation process, mainly in infrastructure development. The opening of new township and residential in former tin mining areas, particularly in the heavy mineral- or tin-bearing alluvial soil in Kuala Lumpur, is a contentious subject in land-use regulation. Construction practices, i.e. reclamation and dredging in these areas are potential to enhance the radioactivity levels of soil and subsequently, increase the existing background gamma radiation levels. This situation is worsened with the utilisation of tin tailings as construction materials apart from unavoidable soil pollutions due to naturally occurring radioactive materials in construction materials, e.g. granitic aggregate, cement and red clay brick. This study was conducted to assess the urbanisation impacts on background gamma radiation in Kuala Lumpur. The study found that the mean value of measured dose rate was 251±6nGyh-1(156-392nGyh-1) and 4 times higher than the world average value. High radioactivity levels of238U (95±12Bqkg-1),232Th (191±23Bqkg-1,) and40K (727±130Bqkg-1) in soil were identified as the major source of high radiation exposure. Based on statistical ANOVA, t-test, and analyses of cumulative probability distribution, this study has statistically verified the dose enhancements in the background radiation. The effective dose was estimated to be 0.31±0.01mSvy-1per man. The recommended ICRP reference level (1-20mSvy-1) is applicable to the involved existing exposure situation in this study. The estimated effective dose in this study is lower than the ICRP reference level and too low to cause deterministic radiation effects. Nevertheless based on estimations of lifetime radiation exposure risks, this study found that there was small probability for individual in Kuala Lumpur being diagnosed with cancer and dying of cancer.
Microbial colonization of prepainted steel, commonly used in roofing applications, impacts their aesthetics, durability, and functionality. Understanding the relevant organisms and the mechanisms by which colonization occurs would provide valuable information that can be subsequently used to design fouling prevention strategies. Here, next-generation sequencing and microbial community finger printing (T-RFLP) were used to study the community composition of microbes colonizing prepainted steel roofing materials at Burrawang, Australia and Kapar, Malaysia over a 52-week period. Community diversity was low and was dominated by Bacillus spp., cyanobacteria, actinobacteria, Cladosporium sp., Epicoccum nigrum, and Teratosphaeriaceae sp. Cultivation-based methods isolated approximately 20 different fungi and bacteria, some of which, such as E. nigrum and Cladosporium sp., were represented in the community sequence data. Fluorescence in situ hybridization imaging showed that fungi were the most dominant organisms present. Analysis of the sequence and T-RFLP data indicated that the microbial communities differed significantly between locations and changed significantly over time. The study demonstrates the utility of molecular ecology tools to identify and characterize microbial communities associated with the fouling of painted steel surfaces and ultimately can enable the targeted development of control strategies based on the dominant species responsible for fouling.
Matched MeSH terms: Construction Materials/microbiology*
The benefits of using structural lightweight concrete in construction industry, particularly in high rise buildings, over normal weight concrete are numerous. The main method of producing structural lightweight concrete is the use of lightweight aggregates instead of ordinary aggregates in concrete. Due to the limited resources for natural and artificial lightweight aggregates, the alternative sources for lightweight aggregates should be discovered from industrial wastes. Oil palm shell (OPS) and oil-palm-boiler clinker (OPBC) are two solid wastes from palm oil industry and are available in abundance in tropical regimes. The use of just OPS as coarse lightweight aggregate in concrete mixture has some drawbacks for concrete. The aim of this study was to investigate engineering properties of a lightweight concrete containing both of these aggregates. For this purpose, in this study, 50% (by volume) of OPS was replaced with OPBC in an OPS lightweight concrete. The test results showed that when OPS was substituted with OPBC, significant improvement was observed in the compressive, splitting tensile and flexural strengths. In addition, initial and final water absorption as well as drying shrinkage strain of blended coarse lightweight aggregate concrete were significantly less than OPS concrete.
Oil-palm-boiler clinker (OPBC) is an agricultural solid waste sourced from the palm oil industry in tropical regions. This study investigates the use of OPBC as coarse aggregate instead of conventional coarse aggregates to produce a greener concrete, which will help in implementing sustainable construction practices by reducing the usage of raw materials. For this purpose, normal weight coarse aggregates was substituted with dry OPBC aggregates up to 75% (by volume) in a high strength normal weight concrete. The effectiveness of this substitution on the properties of the concrete such as workability, density, compressive strength, splitting tensile strength and modulus of elasticity was studied. The slump test results showed that using OPBC in dry condition reduced the workability of the concrete and therefore can be used up to 50% of the total volume of coarse aggregate. Concrete containing 50% OPBC can be considered as semi-lightweight concrete with high strength. Using OPBC in concrete reduced the splitting tensile strength and modulus of elasticity, however, the reduction was not significant.
Aluminum (Al) is a standard material that has been used as a filter for ionising radiation however for polyvinyl chloride (PVC) there is no solid evidence to support but has been recommended. PVC has been selected as a potential filter material due to it is a long lasting constructing material and very durable, which can be used in a variety of application. The purpose of this study was to observe the effect of PVC on entrance surface dose (ESD) values as compare to the standard X-ray filter of Al. The effect of varying thickness of the materials and difference exposure settings were observed and compared to each other. From this study, the percentage difference for both PVC and Al thickness is less than ± 25.00 % shows that PVC has a potential to be used as one of the filter materials due to its ability to reduce the ESD value
This aim of this study is to study the effects of various contents of Automotive Windscreen Glass Waste Powder (WGWP) as a cement replacement. Mortar incorporating several compositions of WGWP (0%, 5%, 10%, 15% and 20%) by weight of cement was prepared. Three batching systems of cement to sand (C:S) ratios of 1:2.5 superplasticizers (SP), 1:3.0 SP and 1:3.5 SP was also employed. Fixed water to cement (w/c) ratio of 0.5 was used. The samples were water cured and the assessment of the strength performance of mortar cubes carried out at 7 and 28 days. Studies conducted have shown that WGWP has good pozzolanic properties. In term of compressive strength, it was observed that employing C:S ratio of 1:3.5 SP is better than 1:2.5 SP and 1:3.0 SP.
The volume of waste generated from surface coating industries is of global concern. The disposal of this waste in the form of effluent has put enormous pressure on land and also poses as a health hazard when it leaches into soil and underground water. The study aims to examine the utilization of vinyl acetate effluents from water based paint factories as an admixture in concrete. Concrete specimens containing 0%, 2.5%, 5% and 10% of vinyl acetate effluents by weight of cement were prepared. The specimens were tested for drying shrinkage for 28 days and porosity was tested using mercury intrusion porosimetry. Findings show that concrete containing various proportions of vinyl acetate effluents manifests higher shrinkage behaviour compared to the control item. An investigation of pore size distribution reveals that polymer effluents have particles size larger than 50 nm which are categorize as macroporous in accordance to IUPAC classification. It can be concluded that adding polymer vinyl acetate effluents affects concrete deformation due to the condition of its pore structures. The utilization of this material may provide beneficial effect in terms of the durability performance of concrete and minimize environmental pollution.
The importance of the performance of concrete cannot be neglected since it is the early indicator of its physical and mechanical properties. It became more important when material with different physical properties than normal material such as rubber tire was used as concrete constituent. This paper presented apart of research result conducted on mortar and concrete with crumb rubber. Crumb rubber was replaced at 10%, 15% and 20% as sand replacement by volume. In addition, ordinary Portland cement was added to silica fume at 10% and 15% by weight. The properties measured in this study are air content and workability test. As for workability, superplasticizers were constantly used at 1% dosage for all mortar mixture, and 0.5% to 0.7% for concrete mixture. The air content was set at 4% to 6% and mortar flow test was conducted on a steel plate, shocked 15 times in 15 seconds and concrete slump test was carried out using slump cone equipment. Pressure method was used to measure air content. All mixes were done in a controlled room temperature. Results showed that when CR was added in the mixture segregation was observed in mortar requiring a high dose of superplasticizer to be added to improve the workability while air-modifying agent was used to reduce the mortar air content. In concrete mixture, low dosage of superplasticizers was required for workability and air-entrained agent was injected into the mixture to increase the air content between 4%-6%.
In accordance upon conservation efforts, this research emphasizes on prevention of
environmental pollution and considers the elements of sustainable of infrastructure
construction materials, which is interlocking pavement block. The development of this
innovative product apply the concept of 3Rs and waste to wealth by using the
agricultural waste product, coconut shell, where widely available with very minimum
cost worldwide especially in tropical country such as India, Indonesia, Philippines,
Thailand and Malaysia. The main objective of this research is to produce an
environmental friendly product with a good quality, low cost and lightweight known as
Green Interlocking Pavement (GIP Block). The chemical composition of coconut shell
ash and ordinary Portland cement being identified and compared to know whether it
is able to react as a good binder in the mixture or not. The quality of GIP Block
considered is compressive strength, water absorption and bulk density. All the blocks
were curing in seven and 28 days before implementing the entire test. The existing
interlocking pavement used as bench mark and GIP Block 0% of proportion of coconut
shell ash used as control variables. The specimen of the interlocking pavement
prepared in this research is 10%, 20% and 30% proportion of coconut shell ash to
partially replace the quantity of cement. The ratio of the interlocking pavement apply
in this research is 1:2 which stand for one part cement and two part of sand. The
findings withdrawn from this research are: first, the chemical characteristic of the
coconut shell ash and cement. Second, the value of bulk density slightly reduces as the
percentage of coconut shell ash increases. Third, the additional of coconut shell ash to
partially replace the quantity of cement in the product reduce the compressive
strength and increase the percentage of water absorption.
Ordinary Portland Cement (OPC) is widely used by the construction industry. Research to find the precise proportion of cement replacement material which can be used to produce a product called Ternary Blended Cement (TBC) is not new. The objective of this study is to determine the effect of POFA and SF as TBC on the heat of hydration and compressive strength of mortar. Before producing TBC, specimens using BBC is required. Mix design proportion for POFA and SF are 5%, 10%, 15%, and 20%. Mix design proportion TBC are chose from the highest compressive strength value achieved at 7 days of curing. This research found the heat of hydration of TBC containing 20% POFA and 5% SF is high in the beginning to drop at the end of hydration process in addition to producing lower compressive strength.
Sawdust is considered a waste material and a number of innovative ways are being taken to mitigate its effects on the environment. The use of sawdust as additional admixture in cement-sand brick production is an alternative option to mitigate the problem. In this study, three different types of cement-sand brick mixture in proportion of 1%, 2% and 3% of sawdust added to the normal mixture are prepared. Compression test was conducted on the brick mixture and results indicated 1% sawdust satisfy the Class 1 loadbearing brick whilst the 2% sawdust is slightly above the minimum required strength of 5.2 MN/ m2 for an ordinary quality brick set by the Standards MS 76:1972. Thus, the use of sawdust as admixture in cement-sand brick should not exceed 3%.
Kenaf fibre is one of the natural fibers that has received much attention of many researchers because of its good properties and flexible use. Kenaf fibre composites have been proposed as interior building materials. In this study, the recycling effect on the kenaf PVC wall panel is focused. The main objective of this study is to determine the mechanical properties of different types of kenaf PVC wall panels. The samples were formulated based on the first and third recycling process. The specimens were subjected to several types of tests, namely, tensile, izod impact, flexural and hardness based on ASTM D3039, ASTM D256, ASTM D7264 and ASTM D785, respectively. The results indicate that the mechanical properties of the third recycled kenaf PVC wall panel product is better than the virgin and first recycled specimen. This shows that the recycling process enhances the mechanical properties of the product. On the other hand, the hardness of the specimen decreases after first recycling due to the reheating effect.
Road distress results in high maintenance costs. However, increased understandings of asphalt behaviour and properties coupled with technological developments have allowed paving technologists to examine the benefits of introducing additives and modifiers. As a result, polymers have become extremely popular as modifiers to improve the performance of the asphalt mix. This study investigates the performance characteristics of epoxidized natural rubber (ENR)-modified hot-mix asphalt. Tests were conducted using ENR-asphalt mixes prepared using the wet process. Mechanical testing on the ENR-asphalt mixes showed that the resilient modulus of the mixes was greatly affected by testing temperature and frequency. On the other hand, although rutting performance decreased at high temperatures because of the increased elasticity of the ENR-asphalt mixes, fatigue performance improved at intermediate temperatures as compared to the base mix. However, durability tests indicated that the ENR-asphalt mixes were slightly susceptible to the presence of moisture. In conclusion, the performance of asphalt pavement can be enhanced by incorporating ENR as a modifier to counter major road distress.
Matched MeSH terms: Construction Materials/analysis*
Environmental concerns have significantly influenced the construction industry regarding the identification and use of environmentally sustainable construction materials. In this context, enzymes (organic materials) have been introduced recently for ground improvement projects such as pavements and embankments. The present experimental study was carried out in order to evaluate the compressive strength of a sedimentary residual soil treated with three different types of enzymes, as assessed through a California bearing ratio (CBR) test. Controlled untreated and treated soil samples containing four dosages (the recommended dose and two, five and 10 times the recommended dose) were prepared, sealed and cured for four months. Following the curing period, samples were soaked in water for four days before the CBR tests were administered. These tests showed no improvement in the soil is compressive strength; in other words, samples prepared even at higher dosages did not exhibit any improvement. Nuclear magnetic resonance (NMR) spectroscopy tests were carried out on three enzymes in order to study the functional groups present in them. Furthermore, X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) tests were executed for untreated and treated soil samples to determine if any chemical reaction took place between the soil and the enzymes. Neither of the tests (XRD nor FESEM) revealed any change. In fact, the XRD patterns and FESEM images for untreated and treated soil samples were indistinguishable.