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Exploratory Study of Oil Palm Shell as Partial Sand Replacement in Concrete
Abstract
Malaysia being one of the world largest palm oil producers has been disposing oil palm shell, which is a by-product from palm oil mill thus causing negative impact to the environment. At the same time, extensive mining of natural river sand in large amount to meet the increasing demand of concrete production for the use in rapidly developing construction industry has posed the risk of natural aggregate depletion and ecological imbalance in future. The effect of finely Crushed Oil Palm Shell (COPS) as partial sand replacement material in concrete mix towards density and compressive strength was investigated in this study. Total of five mixes consisting various content of crushed oil palm shell as partial sand replacement ranging from 0, 25, 50, 75 and 100% were prepared in form of cubes. All the specimens were water cured before tested at 7, 14 and 28 days. Compressive strength was conducted in accordance to BSEN 12390. Generally, the compressive strength and density decrease with the increase in the crushed oil palm shell replacement level. Between 50 to 75% replacement, the mix produced possess lower density enabling it to be categorized as lightweight concrete and has the potential to be used as non-load bearing structure. The application in structural concrete material is suited for mix consisting around 25% of crushed oil palm shell.
... However, the quantity of sand harvested from the nature is possible to be controlled by introducing other waste materials that able to function as partial sand replacement material. Realization on the importance of managing the resources smartly for sustainable environment, has inspired local researchers [4][5][6][7][8] to investigate the potential existing waste materials as partial fine aggregate in concrete. So far, no literature review is available on the use of foamed concrete waste as partial sand replacement in concrete. ...
Environmental degradation due to excessive sand mining dumping at certain places and disposal of foamed concrete block waste from lightweight concrete producing industry are issues that should be resolved for a better and cleaner environment of the community. Thus, the main intention of this study is to investigate the potential of foamed concrete block waste as partial sand replacement in concrete production. The foamed concrete waste (FCW) used in this research that were supplied by a local lightweight concrete producing industry. The workability and compressive strength of concrete containing various percentage of foamed concrete waste as partial sand replacement has been investigated. Prior to the use, the foamed concrete waste were crushed to produce finer particles. Six concrete mixes containing various content of crushed foamed concrete waste that are 0%, 10%, 20%, 30%, 40% and 50% were used in this experimental work. Then the prepared specimens were placed in water curing until the testing age. Compressive strength test and flexural strength tests were conducted at 7, 14 and 28 days. The result shows that integration of crushed foamed concrete waste as partial sand replacement in concrete reduces the mix workability. It is interesting to note that both compressive strength and flexural strength of concrete improves when 30% crushed foamed concrete waste is added as partial sand replacement.
... Also, an increasing percentage of OPS as a sand replacement caused a higher reduction in strength. A similar trend has been reported by other researchers (Muthusamy et al., 2013), confirming the best performance of concrete with 25% OPS. Mannan & Ganapathy (2002) also reported that the compressive strength development in concrete mixtures prepared with OPS was almost 49%-55% lower than in the reference sample. ...
Oil palm shell (OPS) in concrete is well studied as an alternative material of fine aggregate in concrete, as a way to use agricultural waste, and helps to contribute to environmental sustainability and economical construction cost. However, OPS addition will lead to lower properties of the concrete, and much research focuses on treating the OPS to overcome it. Many previous works focused on replacement without examining the effect of different particle sizes of OPS. Hence, this study focuses on the performance of concrete with different particle sizes of OPS as sand replacers in concrete at 25% and 50%. The physical and permeability properties of concrete prepared with OPS particle sizes in the ranges between 600μm to 4.75mm (L), 300μm to 1.18mm (M), and of less than 600μm (S) and two different percentages of 25% and 50% by weight as sand replacement are examined. More than 200 cubes, cylinders, and prisms were tested to determine their physical, mechanical, and permeability properties. The workability was measured by the slump height, the mechanical properties by the compressive strength test, flexural strength test, splitting tensile test, ultrasonic pulse velocity (UPV) test, and rebound hammer test. While the permeability properties by the water penetration test, sorptivity test, and rapid chloride permeability test. The findings showed that increasing the particle sizes of OPS would reduce concrete’s physical and permeability properties. The optimum OPS particle size for structural concrete grade 30 is less than 600μm. With OPS particles of 600um, green concrete using OPS can be made for medium to low-strength applications in the construction industry.
... Prior studies evaluated the physical and mechanical properties of concrete containing oil palm shell (OPS) and oil palm boiler clinker (OPBC) as aggregate [6][7][8][9][10][11][12]. However, no study assesses the thermophysical properties of concrete containing OPBC as fine and coarse aggregate. ...
Replace the normal weight aggregate with wastes or by-products materials is an appropriate method for producing a sustainable cement-based material. The replacement helps to have an energy-efficient component that reduces environmental impact. Time lag and decrement factors are vital wall system variables to evaluate thermal energy consumption in buildings. Thus, this study investigates the thermophysical properties of an innovative sustainable mortar and concrete containing oil palm boiler clinker (OPBC) as fine and coarse aggregate through an experimental approach. Then, time lag and decrement factor in different wall systems are calculated based on EN ISO 13786 through Python 3.7 (NumPy and math modules) and optimized using the response surface methodology (RSM). The results indicated mortar with OPBC has a slightly reduced decrement factor and increased time lag compared to a typical mortar. More significantly, the decrement factor of OPBC concrete was reduced by 34%, and its time lag increased up to 58% compared to conventional concrete.
... Prior studies evaluated the physical and mechanical properties of concrete containing different types of agro-waste aggregate such as rice husk [10,11], tobacco waste [12], leather [13], etc. The recent studies are related to the oil palm shell (OPS) and oil palm boiler clinker (OPBC) concrete [14][15][16][17][18][19][20]. However, only a few of these studies evaluated the thermal properties of the mortar or concrete with OPS as an aggregate [21][22][23][24]. ...
... Nowadays the most common method of determining the concrete strength is to test in simple compression [12]. The concrete with 10% POS and Pumice replacement exhibited the best strength which is over 33. ...
This paper presents an investigation to make the study on workability and strength properties of concrete which is made by Lightweight Aggregates {i.e. Palm Oil Shell (POS) and Pumice Aggregate (PA)}as coarse aggregate. A series of tests conducted in lab containing Slump test, Compaction Factor test, Schmidt Hammer test and Compressive Strength test was led on concrete made by ordinary aggregate as normal weight sample and concrete formed by different ratios of POS and PA separately i.e. 10% to 50% of dry weight of coarse aggregate. All the specimens were underwater for 3, 7 and 28 days as curing stage. In this experimental study, an effort has been made to concentrate the properties of a lightweight concrete M30 using the lightweight aggregate (POS and PA) as a partial replacement to coarse aggregate. The test results indicate that with the increasing amounts of normal aggregates replaced by POS and PA, the slump test, compaction factor test and strength of the Lightweight Aggregate Concrete (LWAC) has reduced gradually. As water absorption of the LWAC has been increased step by step with the increasing amounts of aggregates replaced by POS and PA. Lastly, it is concluded that the use of POS has great future than compared to PA in the construction of structural lightweight concrete.
... However, the quantity of sand harvested from the nature is possible to be controlled by introducing other waste materials that able to function as partial sand replacement material. Realization on the importance of managing the resources smartly for sustainable environment, has inspired local researchers [4][5][6][7][8] to investigate the potential existing waste materials as partial fine aggregate in concrete. So far, no literature review is available on the use of foamed concrete waste as partial sand replacement in concrete. ...
Environmental degradation due to excessive sand mining dumping at certain places and disposal of foamed concrete block waste from lightweight concrete producing industry are issues that should be resolved for a better and cleaner environment of the community. Thus, the main intention of this study is to investigate the potential of foamed concrete block waste as partial sand replacement in concrete production. The foamed concrete waste (FCW) used in this research that were supplied by a local lightweight concrete producing industry. The workability and compressive strength of concrete containing various percentage of foamed concrete waste as partial sand replacement has been investigated. Prior to the use, the foamed concrete waste were crushed to produce finer particles. Six concrete mixes containing various content of crushed foamed concrete waste that are 0%, 10%, 20%, 30%, 40% and 50% were used in this experimental work. Then the prepared specimens were placed in water curing until the testing age. Compressive strength test and flexural strength tests were conducted at 7, 14 and 28 days. The result shows that integration of crushed foamed concrete waste as partial sand replacement in concrete reduces the mix workability. It is interesting to note that both compressive strength and flexural strength of concrete improves when 30% crushed foamed concrete waste is added as partial sand replacement.
... One of the solutions to this problem is to find locally available waste material and integrate it as partial sand replacement in concrete production. This idea has motivated some researchers [2,3,4,5,6] to investigate the possibility of introducing waste material to function as partial sand substitute in concrete production. ...
The increasing demand for natural river sand supply for the use in construction industry along with the issue of environmental problem posed by the dumping of cockle shell, a by-product from cockle
business have initiated research towards producing a more environmental friendly concrete. This research explores the potential use of cockle shell as partial sand replacement in concrete production. Cockle shell used in this experimental work were crushed to smaller size almost similar to sand before mixed in concrete. A total of six concrete mixtures were prepared with varying the percentages of cockle shell viz. 0%, 5%, 10%, 15%, 20% and 25%. All the specimens were subjected to continuous water curing. The compressive strength test was conducted at 28 days in accordance to BS EN 12390. Finding shows that integration of suitable content of crushed cockle shell of 10% as partial sand replacement able to enhance the compressive strength of concrete. Adopting crushed cockle shell as partial sand replacement in concrete would reduce natural river sand consumption as well as reducing the amount of cockle shell disposed as waste.
... Approach taken to reduce utilization of natural sand by partially replacing it with other material would prolong the availability of this material for future generation and contribute towards well balanced ecosystem. As such, with the understanding that the best alternative to attain sustainable development of the concrete industry is through use of by-product instead of raw materials in concrete [5], there are researchers [6,7,8] who has attempted to integrate waste material as partial sand replacement in concrete. ...
This research investigated sulphate resistance of aerated concrete containing palm oil fuel ash as partial sand replacement. Plain aerated concrete with 100% river sand was used as control specimen. Aerated concrete containing palm oil fuel ash was prepared by integrating 30% of the ground palm oil fuel ash as partial sand replacement. For strength determination, both mixes which cast in form of cubes were subjected to water curing up to 90 days. The compressive strength test was carried out in accordance to BS EN 12390-3 at 7, 28 and 90 days. The sulphate resistance of concretes was investigated by measuring the length change of mortar which immersed in 10% Sodium sulphate solution after water cured for 28 days. The measurement of length was taken on weekly basis following the procedure outlined in ASTM C1012-13. Aerated concrete containing palm oil fuel ash exhibits continuous strength development as curing age become longer. Integration of palm oil fuel ash makes the concrete microstructure to be denser through formation of secondary C-S-H gel.The pozzolanic reaction also reduces amount of calcium hydroxide that can react with sulphate ion to form gypsum and ettringite which cause concrete deterioration. It is concluded that using ground palm oil fuel ash as partial sand replacement assist aerated concrete to exhibit higher compressive strength and better durability to sulphate attack.
... In relation to those issues, the abundantly available oil palm shell has inspired researchers [5,6] in attempting to produce more environmental friendly concrete by using this by-product as one of the mixing ingredient. Being hard and does not deteriorate easily inside hardened concrete, makes oil palm shell suitable to be used as lightweight aggregate. ...
Efforts to reduce quantity of oil palm shell and palm oil fuel ash from being disposed as environmental polluting waste has result in innovation of oil palm shell lightweight aggregate concrete containing palm oil fuel ash as partial cement replacement. The current investigation looks into the effect of curing methods on density and compressive strength performance of this newly modified lightweight concrete. Plain concrete consist of 100% OPC were used as control specimen and another one is produced by integrating 20% ground palm oil fuel ash by weight of cement. The specimens were produced in form of cubes (100mmx100mmx100mm) and subjected to different curing method up to 60 days. Four types of curing method were applied namely continuous water curing, sprayed curing, air curing and natural weather curing.
Compressive strength test were conducted in accordance to BS EN 12390-3 at 7, 28 and 60 days. The results
reveal that strength development of oil palm shell lightweight aggregate containing palm oil fuel ash depends on the frequency of water supplied during curing age. Continuous water curing is the most suitable type of curing as it promotes better hydration process and pozzolanic reaction in the concrete mix. Formation of larger amount of C-S-H gel makes the concrete internal structure denser and able to sustain larger load compared to plain concrete.
Sustainability in construction is a priority for both academia and industry to reduce the carbon footprint of the built environment and thus combat climate change. Numerous approaches have been developed on how to tackle this issue, wherein the implementation of eco-efficient concrete is currently considered one of the most effective measures to be applied at the beginning of a building’s life cycle. This edition of the Structural Engineering Document discusses key issues in selecting and incorporating eco-efficient waste materials capable of enhancing the sustainability of structural concrete in construction projects. The cost-efficiency of using recycled aggregates in structural concrete is shown by several world-renowned researchers. Critical evaluations and case studies further highlight the properties and performance of these materials and in various structural applications. Also, novel low-impact binding systems using industrial by-products showcase the importance of continuous research for technically viable alternatives capable of decreasing the huge dependency on ordinary Portland cement. The purpose of this document is to contribute to a broader understanding of the many possibilities for the development of a more sustainable structural concrete, thereby fostering resilient and sustainable construction practices to support the global commitment to environmental responsibility.
Owing to the depletion of natural resources, new alternative materials are emerging in construction industry. Especially, development of alternative binders and aggregates using industrial by-products paves way for the development of eco-friendly concrete. As aggregates occupy about 60-70% of the volume of concrete, new alternative materials developed as a substitute for aggregates are considered as need of the day for achieving sustainability in concrete industry. In the past few decades, many industrial by-products are researched as an alternative for natural aggregates. Ash being the largely produced by-products from different industries, it has huge potential in the development of artificial aggregates. Nevertheless, ashes produced from different sources such as coal, municipal solid waste and biomass have different characteristics and affect the properties of aggregates made out of them. The volume of research works reported on development of ash aggregates all over the globe shows that there is a faster growth rate in the development of alternative aggregates and its utilization in concrete. In this context, the current study aims to review the literature reported on mortar/concrete made of ash aggregates from various sources such as thermal power stations, biomass and municipal solid waste incinerator. The characteristics of different types of ash, development of aggregate and its properties in mortar/concrete are reviewed. Based on the review, future recommendations and directions are provided to utilize more of ash aggregates in the place of natural aggregates to prevent depletion of natural resources.
The negative impacts of cement-based material (CBM) production are way bigger than ever expected. To illustrate the scale of this phenomenon, all the forests in the world, regardless of the fact that they are disappearing at an alarming rate, are not enough to offset even half the environmental impact (EI) of global aggregates and cement production. Thus, it is necessary to promote scientific research and guide more researchers and professionals in the construction industry to investigate the undiscovered sustainability paths, namely for concrete before and after end-of-life. For that purpose, a global and extensive review is made here to provide an overall view of concrete sustainability in all possible paths. Then, each path is organized as follows: (i) brief introduction, (ii) presentation of non-traditional materials and techniques that can be used for the selected strategy, (iii) their limitations and (iv) future trends. The study also identifies what is already known to avoid putting valuable research resources into redundant scientific studies. The following paths of concrete production sustainability were identified: mix composition (e.g. reduce the EI and resources use of binders, aggregates, water and reinforcement), materials manufacturing (e.g. new production techniques of cement, aggregates and steel bars), concrete mixing (e.g. mixer type and mixing method), on-site application (e.g. regular casting and digital concrete/3D printing), and in-service performance (e.g. increase the durability of reinforced concrete and carbon capture and thermal conductivity). On most of these paths, many studies have been made on the same non-traditional materials and techniques and similar outputs were obtained. Yet, many other non-traditional materials and techniques have not been explored before, or are incomplete in terms of the characteristics analysed. More than providing definite solutions, this contribution intends to open the minds of the readers to the vastly unexplored world of “green concrete”.
Appropriate sand for construction is getting scarce in many countries leading to a growing interest in the use of wastes from several origins in mortar and concrete production. This paper investigates the performances of mortar containing the industrial wastes of vegetable synthetic sponges (VSS) as natural sand replacement. After preparation, different amounts of VSS particles (up to 20 wt% of sand replacement) were incorporated in the cementitious matrix containing 20% of silica fume by weight of cement. The use of silica fume improved the cement-aggregate interface leading to reduce the porosity and to increase consequently the mechanical strength. The replacement of the natural sand with VSS improved the thermal performance of the studied composites by causing a decrease of thermal conductivity up to 63% for 20 wt% of sand replacement by VSS. The thermal diffusivity of composites decreased and the specific heat capacity increased. The combination of VSS and silica fume in cementitious materials can largely improve the post-cracking extension and fracture energy, even if the compression strength is reduced. The study showed that the use of vegetable synthetic sponge wastes provides good potential to answer a major challenge: reducing environmental impact of this material while providing a new use with optimum technical properties, as found with 8 wt% of VSS.
Environmental pollution caused by the dumping of oil palm shell (OPS) from palm oil mill and cockle shell from cockle trade has initiated early exploration to discover the potential of these waste incorporated in concrete production. The present research investigates the effect of integrating crushed cockle shell as partial fine aggregate replacement on compressive strength and flexural strength of OPS lightweight aggregate concrete. A total of five mixes were prepared. OPS lightweight aggregate concrete containing 100% river sand was used as control specimen. Other mixes were produced by varying the percentage of crushed cockle shell by weight of sand. All specimens were water cured for 28 days before subjecting it to compressive strength and flexural strength. The finding shows the concrete exhibit strength increment when crushed cockle shell is added as partial fine aggregate replacement. Conclusively, crushed cockle shell has the potential to be used as mixing ingredient in OPS lightweight concrete production.
An immense amount of agricultural waste is produced while growing, harvesting and processing goods; which should be treated as a resource for its prevalence and renewability. While developed countries are concerned with utilization and environmental issues, developing countries are focusing on the economic factors of social housing, especially in rural areas. Fortunately, environmental awareness has been raised in the construction industry by using agricultural waste as partial replacement for fine aggregate, coarse aggregate, reinforcing materials, cement and binders. This review is an attempt to collect world-wide data with references for future estimation possibilities of agro waste application focused on fine aggregate replacement in concrete.
The increasing demand for natural sand supply by concrete industry and rising quantity of palm oil fuel ash, an environmentally polluting solid waste disposed by Malaysian palm oil industry has led to the innovation of aerated concrete containing palm oil fuel ash as partial sand replacement material. This lightweight concrete exhibits improvement in the compressive strength with the incorporation of 30% palm oil fuel ash. However, the long term experimental result of the strength and durability performance of this modified concrete is unavailable. This paper reports the one year result on strength performance of aerated concrete containing palm oil fuel ash when subjected to different curing method and behavior of this material upon exposure to long term sulphate attack. Comparisons are made between behavior of plain aerated concrete mix as control specimen and another mix, aerated concrete with 30% palm oil fuel ash as partial sand replacement. Compressive strength performance of the specimens were observed by placing it in two types of curing regime, water curing and air curing. Durability of the mixes were assessed by exposing the specimens in Sodium sulphate environment. Findings indicate that water curing promotes better pozzolanic reaction in aerated concrete containing palm oil fuel ash, that leads to formation of larger amount of C-S-H gel resulting it to be stronger than control specimen. Integration of palm oil fuel ash consumes calcium hydroxide which is vulnerable to sulphate attack and produces secondary C-S-H gel making the concrete more compact thus enhancing its durability against sulphate attack.
In the last 15 years, the worldwide consumption of natural sand as fine aggregate in mortar/concrete production is very high and many developing countries have encountered some problems in the supply of natural sand in order to meet the increasing demands of construction development. In many countries there is a shortage of natural sand that is suitable for construction. On the other hand, disposal of wastes such as fly ash (FA), bottom ash (BA) and agricultural wastes can be considered as the major environmental challenges. This challenge continues to increase with the increase of these wastes. Therefore, studies have been carried out to find suitable solutions of the shortage of natural sand and the huge increasing in the wastes disposal. One logical option to solve this problem is employing these materials as a part of fine aggregate instead of natural one in mortar/concrete. This paper presents an overview of the previous studies carried out on the use of the previous wastes as a partial or full of natural fine aggregate replacement in traditional mortar/concrete mixtures based on Portland cement (PC). Other cementitious material such as ground basaltic pumice and metakaolin (MK), which can replace part or full of natural fine aggregate was also included. Fresh properties, hardened properties and durability of mortar/concrete containing these waste/cementitious materials as natural fine aggregate replacement have been reviewed.
Issues on preservation of natural river sand from being used excessively in concrete industry has led to the efforts of utilizing palm oil fuel ash, a by-product from palm oil industry as partial sand replacement in production of aerated concrete. This paper reports the effect of curing regime on compressive strength development of aerated concrete containing palm oil fuel ash as partial cement replacement. Two types of mixes were used in this experimental work namely plain aerated concrete acting as control specimen and aerated concrete containing 30% palm oil fuel ash as partial sand replacement. Concrete cubes were subjected to different types of curing namely initial water curing for 7 days followed by air curing, water curing and air curing until the testing date. The compressive strength test was conducted in accordance to BS EN 12390-3 at 7, 14, 28 and 90 days. Application of water curing is the most suitable method to be applied to ensure better strength development in aerated concrete containing POFA as partial sand replacement. Continuous presence of moisture promotes better hydration and pozzolanic reaction leading to formation of extra C-S-H gel and that subsequently make the concrete denser and compressive strength higher.
This paper presents part of the experimental results of an on-going research project to produce structural lightweight concrete using solid waste, oil palm shell (OPS), as a coarse aggregate. Reported in the paper are the compressive strength, bond strength, modulus of elasticity, and flexural behaviour of OPS concrete. It was found that although OPS concrete has a low modulus of elasticity, full-scale beam tests revealed that deflection under the design service loads is acceptable as the span-deflection ratios ranged between 252 and 263, which are within the allowable limit provided by BS 8110. Laboratory investigations show encouraging results and it can be summarised that OPS has good potential as a coarse aggregate for the production of structural lightweight concrete, especially for low-cost housing construction and also for use in earthquake prone areas.
The engineering and transport properties of high-strength green concrete (HSGC) containing up to 60% of ultrafine palm oil fuel ash (POFA) have been studied. POFA obtained from a palm-oil industry was treated via heat treatment to remove excess carbon and ground to a median particle size of about 2 μm. The ultrafine POFA obtained was then utilized in the production of HSGCs with POFA replacement levels of 0%, 20%, 40% and 60% by mass of ordinary Portland cement. The results show that the treatment processes undertaken results in a highly efficient pozzolan. For fresh concrete, the inclusion of the ultrafine POFA tends to increase the workability of the HSGCs, and retards the setting times in particular at higher POFA contents. In the case of compressive strength, the inclusion of the ultrafine POFA reduces early age strength of the HSGCs at 1, 3 and 7 days, but enhances the strength at 28 days for all HSGCs containing POFA, where strength exceeding 95 MPa was achieved for all the POFA–HSGCs. Whereas the transport properties as assessed via porosity, initial surface absorption, rapid chloride permeability, gas permeability and water permeability tests are significantly improved with the inclusion of the ultrafine POFA, with the HSGC containing 60% POFA exhibiting the greatest improvement at 28 days. Thus, the overall results show that the ultrafine POFA possesses significant potential as an efficient pozzolanic mineral admixture for the production of HSGC with promisingly superior engineering and transport properties.
The mining of sand resources from rivers and ex-mining areas in Selangor state is a common practice
and may lead to destruction of public assets as well as impacts or increase stress on commercial and
noncommercial living resources that utilize these areas. Hydraulic and sediment transport modeling
study were carried out to determine possible sand deposition and their flow towards Selangor river. The
Hydrologic Engineering Centers River Analysis System (HEC-RAS) software were used to perform onedimensional
hydraulic calculations for a full network of natural and constructed channels and to get
input and output information in tabular and graphical formats.The resulting vertical and horizontal
distributions of sediment show encouraging agreement with the field data, demonstrating markedly
different dispersal patterns due largely to the differential settling of the various sand classes. The
assessment of water quality shows that water has been highly polluted immediately downstream of
station at Selangor River due to high concentrations of suspended particles. Transport modeling and
water quality analyses performed have identified major physical environmental impacts. The issue
poses a number of policy questions that are worth to be implemented by the government.
This paper presents an investigation on the flexural behaviour of reinforced concrete beams produced from oil palm shell (OPS) aggregates. Utilising OPS in concrete production not only solves the problem of disposing this solid waste but also helps conserve natural resources. A total of 6 under-reinforced beams with varying reinforcement ratios (0.52% to 3.90%) were fabricated and tested. Data presented include the deflection characteristics, cracking behaviour, ductility indices and end-rotations. The investigation revealed that the flexural behaviour of reinforced OPS concrete beams was comparable to that of other lightweight concretes and the experimental results compare reasonably well with the current Codes of Practice. It was observed that beams with low reinforcement ratios satisfied all the serviceability requirements as per BS 8110.
Polyhydroxyalkanoate (PHA) is a potential substitute for some petrochemical-based plastics. This biodegradable plastic is derived from microbial fermentation using various carbon substrates. Since carbon source has been identified as one of the major cost-absorbing factors in PHA production, cheap and renewable substrates are currently being investigated as substitutes for existing sugar-based feedstock. Plant oils have been found to result in high-yield PHA production. Malaysia, being the world's second largest producer of palm oil, is able to ensure continuous supply of palm oil products for sustainable PHA production. The biosynthesis and characterization of various types of PHA using palm oil products have been described in detail in this review. Besides, by-products and waste stream from palm oil industry have also demonstrated promising results as carbon sources for PHA biosynthesis. Some new applications in cosmetic and wastewater treatment show the diversity of PHA usage. With proper management practices and efficient milling processes, it may be possible to supply enough palm oil-based raw materials for human consumption and other biotechnological applications such as production of PHA in a sustainable manner.
This paper presents use of improved palm oil fuel ash (POFA) as a pozzolanic material in producing high-strength concrete. The POFA was ground by ball mill until the median particle size was reduced to about 10 mum. It was used to replace portland cement, ASTM Type 1, by 10, 20, and 30% by weight of cementitious materials to make high-strength concrete. It was found that high-strength concrete can be achieved by using ground POFA to replace portland cement Type I up to 30%. At the age of 28 days, concretes containing 10, 20, and 30% of ground POFA gave compressive strengths of 81.3, 85.9, and 79.8 MPa, respectively. Concrete with 20% replacement of ground POFA had the highest strength. It is slightly higher than that of concrete containing 5% condensed silica fume and about 92-94% that of 10% condensed silica fume concrete. The ground POFA content up to 30% had slightly effect on lowering the modulus of elasticity of concrete. In addition, the use of ground POFA reduced the peak temperature rise of concrete under semiadiabatic conditions.
Using waste materials for new products is a global trend undergoing rapid development. Recycling materials allows for a more efficient life cycle and contributes to environmental protection. In the construction field, this trend has gained importance because of the shortage of natural resources and because of environmental problems caused by storing building-demolition wastes. This situation has led to the search for new applications for these wastes, and their use as aggregates in concrete is an interesting alternative. In this paper, some characteristics of recycled coarse aggregates obtained by crushing waste ready-mix concrete, as well as the mechanical and curability properties of recycled concretes made by using 25, 50, and 75% of these aggregates, are presented. Recycled concretes show lower compressive strength than conventional concrete for the higher strength level, whereas the durability properties of the two are similar. DOI: 10.1061/(ASCE)MT.1943-5533.0000165. (C) 2011 American Society of Civil Engineers.
Oil palm shell (OPS) is a waste lightweight aggregate originating from the palm oil industry, which is approximately 50% lighter than conventional aggregate. In this study, crushed old OPS was used as coarse aggregate. Compressive strength under different curing conditions and the splitting tensile and flexural strengths were compared with those of the normal weight granite concrete. The test results showed that OPS concrete with a compressive strength in the range of 34-53 MPa has a splitting tensile strength range of 2.8-3.5 MPa and flexural strength range of 4.4-7.0 MPa. The sensitivity of compressive strength of OPS concrete in this study is significantly lower than uncrushed OPS concrete reported in the literature. The sensitivity of OPS concrete, under poor curing regime, can be reduced by decreasing the water/cement ratio, increasing the OPS content or reducing the cement content. It was found that there was no substantial difference in 28-day compressive strength for OPS concretes cured initially for 3, 5 and 7 days. The 28-day compressive, splitting tensile and flexural strengths of OPS concrete was found to be 38%, 28% and 17%, lower than that of granite concrete, respectively.
Natural and artificial pozzolanas have been used to obtain hydraulic binders for over a thousand years. Hardening of pozzolanic cement pastes can result from the reaction between pozzolana and the lime that is added to the mix as hydrated lime or is produced following hydration of portland cement silicates. The pozzolanic reaction does not alter cement clinker hydration; it complements and integrates the hydration process because it results in a lower portlandite content and an increase in calcium silicate hydrates.
The mix design of lightweight concrete using oil palm shell (OPS) as aggregate differs widely from the procedure of mix proportioning for conventional concrete with crushed stone aggregate. The mix design depends on the properties of aggregates. The 28-day compressive strengths of OPS concrete designed according to the ACI method for conventional concrete and methods mentioned in references [A. Short, W. Kinniburgh, Lightweight Concrete, third ed., Applied Science Publishers, London, 1978; M.S. Shetty, Concrete Technology, S. Chand, India, 1993] for lightweight aggregate concrete have been found to be very much less than the targeted design strength of OPS concrete. It is confirmed that the mix design method of ACI and methods mentioned in the above references fail for the design of mix for OPS aggregates. A trial mix design for concrete with OPS as coarse aggregate has resulted in acceptable strength of 24 N/mm2 for 28-day. Fly ash as mineral admixture and calcium chloride as an accelerator have also been used to study the improvement in strength.
Aerated concrete is relatively homogeneous when compared to normal concrete, as it does not contain coarse aggregate phase, yet shows vast variation in its properties. The properties of aerated concrete depend on its microstructure (void–paste system) and composition, which are influenced by the type of binder used, methods of pore-formation and curing. Although aerated concrete was initially envisaged as a good insulation material, there has been renewed interest in its structural characteristics in view of its lighter weight, savings in material and potential for large scale utilisation of wastes like pulverised fuel ash. The focus of this paper is to classify the investigations on the properties of aerated concrete in terms of physical (microstructure, density), chemical, mechanical (compressive and tensile strengths, modulus of elasticity, drying shrinkage) and functional (thermal insulation, moisture transport, durability, fire resistance and acoustic insulation) characteristics.
Contenido: Materiales que producen el concreto; Concreto; Concreto reforzado; Flexión de vigas; Cortante y tensión diagonal en vigas; Torsión; Condiciones de servicio de vigas y losas en una dirección; Compresión y flexión combinadas: columnas; Desarrollo de la adherencia de varillas de refuerzo; Diseño de losas y placas en dos direcciones; Cimentaciones; Estructuras continuas de concreto preesforzado; Introducción al concreto pretensado; Diseño de estructuras de concreto en puentes; Diseño sísmico de estructuras de concreto.
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Synthesis of polyhydr oxyalkanoate from palm oil and some new applications
- K Sudesh
- K Bhubalan
- J A Chuah
- Y K Kek
- H Kamilah
- N Sridevi
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