Nov 2018

Development of environmental friendly rubberized asphalt

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Aug 2017

Study the performance of modified bitumen with polyphosphoric acid

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Aug 2017

Sampling pavement surface condition data at traffic-speed

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Jun 2017

Sampling functional condition indices at traffic-speed

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Jun 2017

Use of incineration bottom ash for road construction in Singapore

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Jul 2016

Recycling of scrap tires for use in asphalt concrete in Singapore

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Jul 2016

Structural management of airfield pavements using effective tools

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Jun 2016

Traffic-speed MTD measurements of asphalt surface courses

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Jun 2016

Traffic-speed MTD measurements of asphalt pavements

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Nov 2015

Use of sedimentary rocks for use in road construction in Singapore

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Jun 2015

Evaluation of RCA concrete for the construction of Samwoh Eco-Green Building

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Jul 2013

Use of high percentage of recycled concrete aggregate in aircraft stand rigid pavement

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Mar 2013

Efficient utilization of recycled concrete aggregate in structural concrete

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Aug 2011

Use of recycled concrete aggregate for the construction of aircraft stand rigid pavement at Singapore Changi Airport

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Aug 2011

Beneficial use of fine recycled concrete aggregate for utility trench reinstatement

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Mar 2011

Use of recycled and secondary aggregates in concrete: An overview

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Nov 2009

Efficient utilization of recycled concrete aggregate for structural concrete applications

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Oct 2009

Field study on the use of recycled concrete aggregate for road trenching works in Singapore

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Oct 2009

Framework and assessment of carbon footprint for direct and indirect carbon contributory inventories of a road construction project in Singapore

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Jul 2008

Beneficial use of recycled concrete aggregate for road construction in Singapore

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Dec 2007

Recycling of waste materials for road construction in Singapore

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samwoh.com SAMWOH | Technical Publications | Sustainable Construction in Singapore

Development of environmental friendly rubberized asphalt

Nov 2018

Conference: 10th International Conference on Road and Airfield Pavement Technology (ICPT), 8 – 10 Aug 2017, Hong Kong

Author(s): A N Win Maung, Y P K Lee & N Y Ho

Bitumen modification has been widely developed to raise the requirement for durability and to achieve long- lasting road surface. There are many types of bitumen modifiers and additives such as polymer (elastomers and plastomers), crumb rubber, natural rubber latex, polyphosphoric acid (PPA) and sulphur. This paper involves a study to evaluate the performance of PPA modified bitumen in comparison with that of styrene-butadiene- styrene (SBS) modified bitumen. The 60/70 penetration grade bitumen was used with different dosages of PPA/SBS to prepare PPA/SBS modified bitumen samples. Standard tests such as rotational viscosity, elastic recovery, dynamic shear (DSR), rolling thin film oven (short term ageing) and multiple-stress creep and recovery (MSCR) were conducted according to performance grade (PG) requirements.

samwoh.com SAMWOH | Technical Publications | Sustainable Construction in Singapore

Study the performance of modified bitumen with polyphosphoric acid

Aug 2017

Conference: 10th International Conference on Road and Airfield Pavement Technology (ICPT), 8 – 10 Aug 2017, Hong Kong

Author(s): A N Win Maung, Y P K Lee & N Y Ho

Bitumen modification has been widely developed to raise the requirement for durability and to achieve long- lasting road surface. There are many types of bitumen modifiers and additives such as polymer (elastomers and plastomers), crumb rubber, natural rubber latex, polyphosphoric acid (PPA) and sulphur. This paper involves a study to evaluate the performance of PPA modified bitumen in comparison with that of styrene-butadiene- styrene (SBS) modified bitumen. The 60/70 penetration grade bitumen was used with different dosages of PPA/SBS to prepare PPA/SBS modified bitumen samples. Standard tests such as rotational viscosity, elastic recovery, dynamic shear (DSR), rolling thin film oven (short term ageing) and multiple-stress creep and recovery (MSCR) were conducted according to performance grade (PG) requirements.

samwoh.com SAMWOH | Technical Publications | Sustainable Construction in Singapore

Sampling pavement surface condition data at traffic-speed

Aug 2017

Conference: 10th International Conference on Road and Airfield Pavement Technology (ICPT), 8 – 10 Aug 2017, Hong Kong

Author(s): K Drenth, F H Ju & J Y Tan

The assessment of the structural and functional pavement condition is nowadays fully machine based and non- destructive equipment does cover all the data input required for a modern PMS approach. A Multi-Laser Vehicle is capable of real time continuous traffic-speed measurements of condition data regarding cracking, ravelling, rutting, roughness, macro texture and road geometrics in a single run using high-speed line-scan cameras for an automated assessments. The system of the Multi-Laser Vehicle equipped with a Laser Crack Measuring System (LCMS) is the most promising development in 3D camera technology with a progressive improvement of capabilities and quality.

This paper discusses the results of the equipment used and does show the continuous measured macro texture based on the MTD as index using the LCMS device in addition to the automated crack detection. A major advantage is that no conversion is required as the volumetric MTD is a direct output. The LCMS based automated MTD analysis is a machine based result not influenced by a human factor such as the Sand Patch. The results allow as well the automated analysis of loss of aggregate which is a major advantage in rating the severity and extent of ravelling in comparison to the non-consistent wind-screen surveys and manual rating of collected images. In addition the sampling of rutting has been validated against the multi-laser profiler approach as well as the IRI based on Inertial Motion Sensors attached to the LCMS units.

samwoh.com SAMWOH | Technical Publications | Sustainable Construction in Singapore

Sampling functional condition indices at traffic-speed

Jun 2017

Conference: 10th International Conference on the Bearing Capacity of Roads, Railways and Airfields (BCRRA), 28 – 30 Jun 2017, Athens, Greece

Author(s): K Drenth, F H Ju & J Y Tan

The assessment of the structural and functional pavement condition is nowadays fully machine based and non-destructive equipment does cover all the data input required for a modern PMS approach. A Multi-Laser Vehicle is capable of real time continuous traffic-speed measurements of condition data regard- ing cracking, ravelling, rutting, roughness, macro texture and road geometrics in a single run using high-speed line-scan cameras for an automated assessment. The system of the Multi-Laser Vehicle equipped with a Laser Crack Measuring System (LCMS) is the most promising development in 3D camera technology with a pro- gressive improvement of capabilities and quality.

This paper discusses the results of the equipment used as well as the accuracy and repeatability achieved. Shown is as well the continuous measured macro texture based on the Mean Texture Depth (MTD) as index using the LCMS device in addition to the automated crack detection. A major advantage is that no conversion is required as the volumetric MTD is a direct output. The LCMS based automated MTD analysis is a machine based result not influenced by a human factor such as the Sand Patch. The results allow as well the automated analysis of loss of aggregate which is a major advantage in rating the severity and extent of ravelling in com- parison to the non-consistent wind-screen surveys and manual rating of collected images. In addition to the MTD the sampling of rutting has been validated against the multi-laser profiler approach as well as the Inter- national Roughness Index (IRI) based on Inertial Motion Units (IMU’s) attached to the LCMS sensors.

samwoh.com SAMWOH | Technical Publications | Sustainable Construction in Singapore

Use of incineration bottom ash for road construction in Singapore

Jun 2017

Conference: World Sustainable Built Environment (WSBE) Conference, 5 – 7 Jun 2017, Hong Kong

Author(s): N Y Ho, Y P K Lee, C C Yap, K K Tong & C T Lim

Every year, about 600,000 tonnes of incineration ash is produced in Singapore. The ash comprises bottom ash and fly ash. The bottom ash contains less leachable metals of concern and soluble salts and has a great potential for utilization. In 2008, Samwoh participated in a trial initiated by Land Transport Authority to evaluate the use of bottom ash in road construction. The study comprises laboratory tests and field trial to evaluate the properties of the bottom ash which was processed using a patented technology. The bottom ash was used for the construction of road base and subbase. The test results showed that the processed bottom ash meets all the relevant regulatory requirements.

samwoh.com SAMWOH | Technical Publications | Sustainable Construction in Singapore

Recycling of scrap tires for use in asphalt concrete in Singapore

Jul 2016

Conference: 8th International Conference on Maintenance and Rehabilitation of Pavements (MAIREPAV), 27 – 29 Jul 2016, Singapore

Author(s): N Y, Ho,Y P K, Lee & A L, Moe

In Singapore, a significant amount of scrap tires is generated every year. The applications of the scrap tires are typically low in economic value and some are disposed in landfills. The disposal of scrap tires caused environmental problems and there is limited land fill space in Singapore. Hence, there is a need to recycle scrap tires for more beneficial applications. This paper describes a study that was carried out to evaluate the use of crumb rubber recycled from scrap tires in asphalt concrete. The study was conducted with respect to open-graded wearing course (OGW) which is commonly used for highways in Singapore. Two types of bitumen, straight bitumen of penetration grade 60/70 and polymer modified bitumen of performance grade PG76 were used for controlled samples. The samples were prepared by wet mixing and dry mixing methods and the results were compared with those of controlled samples. The performance properties were evaluated by means of resilient modulus, Los Angeles abrasion loss, tensile strength ratio and dynamic creep tests.

samwoh.com SAMWOH | Technical Publications | Sustainable Construction in Singapore

Structural management of airfield pavements using effective tools

Jul 2016

Conference: 8th International Conference on Maintenance and Rehabilitation of Pavements (MAIREPAV), 27 – 29 Jul 2016, Singapore

Author(s): K, Drenth, F H, Ju & J Y, Tan

The volume of air traffic continues to grow, resulting in an increasing frequency of aircraft movements as well as increase in gross weight. To cope with such growth it is necessary to make optimal use of all available runways, taxiways and aprons. An optimum utilization of such resources also means that maintenance has to be structured into a planned approach making it a prerequisite to have insight knowledge of the performance of the pavements, asphalt as well as concrete. By carrying out the right maintenance at the right time, the airport will reduce the overall need for maintenance, which in turn will produce economic benefits.

The pressure on the availability of all airport pavements at any time does mean that the condition of pavements has to be forecasted based on reliable performance indicators and performance models. For many airports the PCI procedure is the primary tool for forecasting and budgeting. A pavement condition is often periodically evaluated using various condition measurements such as (automated) visual condition surveys, non-destructive deflection testing (PCN), roughness (BBI) and skid resistance. Bringing all this data together in a PMS like PAVER will allow to visualize the condition of the pavement sections in GIS-based maps.

This paper discusses the issues busy international airports do face with the increase in movements approaching saturation levels of the runways leaving ample time for the minimum maintenance required. Machine-based condition measuring tools are required in combination with a long term prediction of the structural as well as functional condition based on proper historic information. This requires proper pavement management to avoid critical maintenance to be executed beyond the point of no return

samwoh.com SAMWOH | Technical Publications | Sustainable Construction in Singapore

Traffic-speed MTD measurements of asphalt surface courses

Jun 2016

Conference: 8th International Conference on Maintenance and Rehabilitation of Pavements (MAIREPAV), 27 – 29 Jul 2016, Singapore

Author(s): K, Drenth, F H, Ju & J Y, Tan

An important characteristic of a pavement surface is texture. Texture does relate to friction, noise and ravelling and does change over time due to aging, contamination and loss of aggregate. As such it is an important characteristic triggering maintenance measures when it does not meet the requirements anymore. The standard procedure is to measure texture based on the Mean Profile Depth (MPD), which is a single point measurement along a longitudinal track sampled at a high frequency. The actual requirement is a volumetric 3D based result to be directly representative for the characteristics required without the need of a conversion from a 2D based test.

This study was conducted to validate at traffic-speed measured MTD’s using a Laser Crack Measurement System (LCMS) with the results of the static Sand Patch Test Method (SPTM). The LCMS does measure the volumetric properties of the road surface continuously over its full width and length based on 250 x 250mm squares. The evaluation did include static SPTM’s, a static ELAtextur device measuring MPD and a traffic-speed road surface profiler equipped with a texture laser measuring MPD as well. The test were conducted over different time periods and multiple runs at a validation site used for calibrating testing equipment operating at roads in Singapore.

This paper discusses the results of the equipment used and does show the very good correlation between the SPTM results and the MTD’s based on the LCMS device. A major advantage is that no conversion is required as the volumetric MTD is a direct output. The LCMS based automated MTD analysis is a machine based result not influenced by a human factor such as the SPTM. The results allow as well the automated analysis of loss of aggregate which is a major advantage in rating the severity and extent of ravelling in comparison to the non-consistent wind-screen surveys and manual rating of collected images. However, the next generation LCMS sensors will require an improved vertical resolution to improve on the reliability of ravelling for finer textured surface courses.

samwoh.com SAMWOH | Technical Publications | Sustainable Construction in Singapore

Traffic-speed MTD measurements of asphalt pavements

Jun 2016

Conference: CROW Infra Days 2016, 22 – 23 Jun 2016, Papendal, Netherlands

Author(s): K, Drenth, F H, Ju & J Y, Tan

An important characteristic of a pavement surface is texture. Texture does relate to friction, noise and ravelling and does change over time due to aging, contamination and loss of aggregate. As such it is an important characteristic triggering maintenance measures when it does not meet the requirements anymore. The standard procedure is to measure texture based on the Mean Profile Depth (MPD), which is a single point measurement along a longitudinal track sampled at a high frequency. The actual requirement is a volumetric 3D based result to be directly representative for the characteristics required without the need of a conversion from a 2D based test.

This study was conducted to validate at traffic-speed measured MTD’s using a Laser Crack Measurement System (LCMS) with the results of the static Sand Patch Test Method (SPTM). The LCMS does measure the volumetric properties of the road surface continuously over its full width and length based on 250 x 250mm squares. The evaluation did include static SPTM’s and a traffic-speed road surface profiler equipped with a texture laser measuring MPD as well. The test were conducted over different time periods and multiple runs at a validation site used for calibrating testing equipment operating at roads in Singapore. 

This paper discusses the results of the equipment used and does show the very good correlation between the SPTM results and the MTD’s based on the LCMS device. A major advantage is that no conversion is required as the volumetric MTD is a direct output. The LCMS based automated MTD analysis is a machine based result not influenced by a human factor such as the SPTM. The results allow as well the automated analysis of loss of aggregate which is a major advantage in rating the severity and extent of ravelling in comparison to the non-consistent wind-screen surveys and manual rating of collected images. However, the next generation LCMS sensors will require an improved vertical resolution to improve on the reliability of ravelling for finer textured surface courses.

samwoh.com SAMWOH | Technical Publications | Sustainable Construction in Singapore

Use of sedimentary rocks for use in road construction in Singapore

Nov 2015

Conference: 33rd Conference of the ASEAN Federation of Engineering Organizations (CAFEO), 22 – 26 Nov 2015, Penang, Malaysia

Author(s): N Y, Ho, Y P K, Lee, A L, Moe, P Y C, Leong & W, Zhang

In Singapore, about 3.7 million m3 of sedimentary rocks have been excavated from the Jurong Rock Cavern project. Due to limited landfill space, this posed potential storage problems. Hence, there is a need to use the rock for beneficial applications. This paper describes a study that was carried out to investigate the use of sedimentary rocks in asphaltic concrete for road construction. The study was conducted with respect to asphalt wearing course and binder course. Based on the laboratory tests, the results showed that with some modification, the asphaltic concrete containing sedimentary rocks can provide comparable performance as conventional asphaltic concrete containing granite.

samwoh.com SAMWOH | Technical Publications | Sustainable Construction in Singapore

Evaluation of RCA concrete for the construction of Samwoh Eco-Green Building

Jun 2015

Journal: Magazine of Concrete Research, Vol. 65, Issue 12, pp. 633 – 644, Jun 2015. Institution of Civil Engineers (ICE), UK

Author(s): N Y, Ho, Y P K, Lee, W F, Lim, K C, Chew, G L, Low & S K, Ting

This paper describes a study conducted to evaluate the use of concrete containing up to 100% recycled concrete aggregate (RCA) for the construction of a commercial building known as the Samwoh Eco-Green Building in Singapore. The study is a continuation of research which established that concrete produced with RCA can achieve strength comparable to that of normal concrete produced with natural aggregate for structural applications by using a rational mix design approach. The present study was carried out to evaluate the effects of RCA on other engineering and durability properties of concrete, including compressive strength, flexural strength, tensile splitting strength, creep strain, water permeability, initial surface absorption, chloride ingress and sulfate resistance. With normal concrete serving as the basis for comparison, the experimental data showed that comparable compressive strength, flexural strength and tensile splitting strength were attainable for concrete containing up to 100% RCA. Although concrete with 100% RCA exhibited higher creep strain and initial surface absorption rate as well as lower resistance to water permeability, chloride ingress and external sulfate attack, the effects on the concrete performance are insignificant. On the whole, the research study suggests that RCA concrete can be designed to meet the specifications for structural applications which led to the successful completion of the Samwoh Eco-Green building.

samwoh.com SAMWOH | Technical Publications | Sustainable Construction in Singapore

Use of high percentage of recycled concrete aggregate in aircraft stand rigid pavement

Jul 2013

Conference: 8th International Conference on Road and Airfield Pavement Technology (ICPT), 14 – 16 Jul 2013, Taipei, Taiwan

Author(s): N Y, Ho, Y P K, Lee, T F, Fwa, J Y, Tan, W F, Lim, E S, Teoh, S, Tan & W S, Chew

This paper describes a study that was carried to investigate the use of recycled concrete aggregate (RCA) in aircraft stand rigid pavement at the Singapore Changi Airport. The study aimed to recycle the concrete waste generated from the demolition of the existing aircraft stand rigid pavement to reconstruct the aircraft stand rigid pavement. The study was a continuation of a previous work in which 20% of RCA was used in the rigid pavement. In this study, laboratory tests were carried out to evaluate the use of up to 100% of RCA in rigid pavement. The test properties that were evaluated include compressive strength, flexural strength, drying shrinkage and resistance to chloride ingress. The study showed that it is viable to incorporate high RCA content in concrete.

samwoh.com SAMWOH | Technical Publications | Sustainable Construction in Singapore

Efficient utilization of recycled concrete aggregate in structural concrete

Mar 2013

Journal: Journal of Materials in Civil Engineering, Vol. 25, Issue 3, pp. 318 – 327, 1 Mar 2013. American Society of Civil Engineers (ASCE), US

Author(s): N Y, Ho, Y P K, Lee, W F, Lim, T, Zayed, K C, Chew, G L, Low & S K, Ting

In Singapore, the applications of recycled concrete aggregate (RCA) are limited to nonstructural concrete, road construction, and backfilling. To realize the beneficial use of RCA, an in-depth study was conducted to evaluate its use in structural concrete. This paper reports the test results of a study that is part of extensive research intended to evaluate the properties of RCA concrete produced by a proposed rational approach in concrete mix design. The key parameters studied include compressive strength, elastic modulus, and drying shrinkage. The results showed that the RCA concrete can be designed to achieve comparable compressive strength and elastic modulus, relative to the corresponding properties of concrete containing natural coarse aggregate (NCA). RCA concrete tends to exhibit higher drying shrinkage strains relative to NCA concrete, but the values are within the recommended limits.

samwoh.com SAMWOH | Technical Publications | Sustainable Construction in Singapore

Use of recycled concrete aggregate for the construction of aircraft stand rigid pavement at Singapore Changi Airport

Aug 2011

Conference: 7th International Conference on Road and Airfield Pavement Technology (ICPT), 3 – 5 Aug 2011, Bangkok, Thailand

Author(s): N Y, Ho, Y P K, Lee, J Y, Tan, C O, How, S Y C, Koh & S W, Ooi

In support of the Singapore government’s goal to achieve sustainable development in the construction industry, Changi Airport Group (CAG) has initiated a project to use recycled concrete aggregate (RCA) that was obtained from the demolition of existing aircraft stand rigid pavement to reconstruct a new aircraft stand rigid pavement at Singapore Changi Airport. The project was carried out by Samwoh Corporation Pte Ltd (Samwoh) and the National University of Singapore (NUS) which involved the demolition of existing aircraft stand rigid pavement, recycling of concrete waste to produce RCA, laboratory tests to assess the quality of the RCA and construction of new aircraft stand rigid pavement using concrete made of RCA. This paper highlights the key considerations involved in the recycling and construction process of aircraft stand rigid pavement using concrete with RCA. The project demonstrates the feasibility of using RCA as an alternative to natural aggregate in concrete for the construction of aircraft stand rigid pavement.

samwoh.com SAMWOH | Technical Publications | Sustainable Construction in Singapore

Beneficial use of fine recycled concrete aggregate for utility trench reinstatement

Aug 2011

Conference: 7th International Conference on Road and Airfield Pavement Technology (ICPT), 3 – 5 Aug 2011, Bangkok, Thailand

Author(s): Y P K, Lee, N Y, Ho, J Y, Tan, S Y, Foo, S S M, Ang & K K, Lee

The Singapore government has been actively promoting the recycling of construction and demolition waste for construction applications with the aim to reduce the reliance on natural aggregates and to alleviate waste disposal problem. The waste can be processed into recycled concrete aggregate (RCA) which can be used as an alternative to natural aggregate. Studies have shown that RCA can be used for many applications such as concreting and road construction works. However, coarse RCA (bigger than 5mm) is largely used in these applications and there is limited usage for the finer RCA. Hence, a joint study was carried out by Samwoh Corporation Pte Ltd, Land Transport Authority and SP PowerGrid to evaluate the use of fine RCA for utility trench reinstatement works which are carried out during maintenance or installation of underground utilities pipes. The study involves laboratory tests and a field trial. The tests results showed that the fine RCA can provide a good alternative to fine natural aggregate for utility trench reinstatement works.

samwoh.com SAMWOH | Technical Publications | Sustainable Construction in Singapore

Use of recycled and secondary aggregates in concrete: An overview

Mar 2011

Conference:  UK-India Education and Research Initiative (UKIERI) Concrete Congress, 8 – 10 Mar 2011, New Delhi, India

Author(s):  R K, Dhir, K A, Paine, J, de Brito, M, Etxeberria, N Y, Ho, C S, Poon & W Y V, Tam

This paper written by some of the World’s leading exponents on the use of recycled and secondary aggregates provides a brief overview of the use of recycled and secondary aggregates for new concrete construction.  It is based on a substantial review, dissection and repackaging of the current known knowledge in the field and is based on authors’ own research, findings and experience.  The paper, in particular, draws upon recent knowledge that has been generated in the past five years as standards and specifications have finally started to provide a route by which these materials can be more readily assimilated into construction.  The paper covers production and processing of recycled aggregates, developments in international standards, the effect of recycled aggregates on strength, deformation characteristics and durability of concrete, and concludes with three international case studies in which recycled aggregates have been used in structural and high performing concrete.

samwoh.com SAMWOH | Technical Publications | Sustainable Construction in Singapore

Efficient utilization of recycled concrete aggregate for structural concrete applications

Nov 2009

Conference: 27th Conference of the ASEAN Federation of Engineering Organizations (CAFEO), 30 Nov – 2 Dec 2009, Singapore

Author(s): N Y, Ho, Y P K, Lee, W F, Lim, S K, Ting, Y, Soh & G L, Low

In recent years, the Singapore government has been actively promoting the recycling of construction and demolition (C&D) waste for construction applications due to limited landfill space and the lack of natural materials available in Singapore. The C&D waste can be processed into recycled concrete aggregate (RCA) which contains mainly aggregate and cementitious materials. At present, the applications of RCA are limited to non-structural concrete and road construction. In line with the nation’s goal to promote sustainable development, a full scale evaluation study was carried out by Samwoh Corporation Pte Ltd, Nanyang Technological University (NTU) and the Building and Construction Authority (BCA) to evaluate the use of RCA for structural concrete. The study involves two stages, namely Stage 1 – Evaluation of the properties of RCA, mechanical and durability characteristics of concrete containing RCA and the mix design, and Stage 2 – Construction and structural health monitoring of a three-storey commercial building using concrete containing RCA. This paper presents some of the results obtained in Stage 1 of the project which include the RCA properties and compressive strength test results. The study was carried out using up to 100% RCA as replacement for granite for various concrete strengths ranging from Grade 20 to Grade 60. The test results showed that the concrete with RCA can be designed to achieve similar strength as compared to concrete with granite.

samwoh.com SAMWOH | Technical Publications | Sustainable Construction in Singapore

Field study on the use of recycled concrete aggregate for road trenching works in Singapore

Oct 2009

Conference: 2nd World Roads Conference, 26 – 28 Oct 2009, Singapore

Author(s): Y P K, Lee, N Y, Ho, J Y, Tan, C C, Yoong, C J, Lim & K K, Lee

Over the years, the Singapore government has been promoting the recycling of concrete waste with the aim to alleviate waste disposal problem due to limited land space in Singapore. The concrete waste can be used as an alternative to natural aggregate which is largely imported from overseas. One of the beneficial uses of concrete waste is for road trenching works which is carried out to install or repair utility pipes such as gas, water, sewage, electrical and telecommunication cables which are located beneath the pavement. This paper describes a field study that was carried out to evaluate the field performance of using concrete waste for road trenching works. The study involved laboratory tests and field performance assessment with respect to riding quality and structural strength.

samwoh.com SAMWOH | Technical Publications | Sustainable Construction in Singapore

Framework and assessment of carbon footprint for direct and indirect carbon contributory inventories of a road construction project in Singapore

Oct 2009

Conference: 2nd World Roads Conference, 26 – 28 Oct 2009, Singapore

Author(s): B S, Baliyan, Y S, Leong & C S, Chan

With the increase in population and the significant increase in traffic on Singapore road network, the demand for more roads and upgrading of existing road network is evident. New roads and upgrading of roads need various construction materials. But as known, the construction industry contributes significant amount of CO2 through usage of fossil fuel and demand for the upstream production of the basic construction materials such as steel, cement and bitumen.

The first part of the paper discusses the carbon footprint framework for road construction, which was developed by Land Transport Authority. The second parts discuss the methodology and the study carried out using the said framework to evaluate the carbon footprint of a road widening project at Tampines Expressway. The study results showed that the three major CO2 emission contributors for road construction works are diesel, cement and steel. The extent of the emission depends on the type of project and the emission factors for each individual contributor.

With the identification of the major CO2 emission contributors for road construction, the next challenge will be on how to limit the carbon contribution from the direct and indirect inventories of road construction materials.

samwoh.com SAMWOH | Technical Publications | Sustainable Construction in Singapore

Beneficial use of recycled concrete aggregate for road construction in Singapore

Jul 2008

Conference: 6th International Conference on Road and Airfield Pavement Technology (ICPT), 20 – 23 Jul 2008, Sapporo, Japan

Author(s): N Y, Ho, Y P K, Lee & J Y, Tan

The construction and demolition (C&D) of building structures and infrastructures has generated large amount of wastes in Singapore. The disposal of the waste posed an environmental problem due to limited land space in Singapore and the rate of waste generation has increased significantly over the years. Moreover, there is a strong dependence on natural aggregate which is imported mainly from overseas. As such, the recycling of C&D waste not only helps to alleviate the waste disposal problem but also provide an alternative to natural materials. This paper describes a study that was carried out on the use of C&D waste in base course for road construction. The study involved laboratory tests to evaluate the properties of the recycled concrete aggregate (RCA) obtained from the processing of C&D waste and to analyze the performance of base course produced with RCA. A field trial was also carried out to evaluate the field performance of the base course.

samwoh.com SAMWOH | Technical Publications | Sustainable Construction in Singapore

Recycling of waste materials for road construction in Singapore

Dec 2007

Conference: 5th Asia Pacific Conference, 7 – 8 Dec 2007, Singapore

Author(s): Y P K, Lee & N Y, Ho

The recycling of waste materials has become one of the key interests of the Singapore government. The disposal of waste materials posed an environmental problem due to limited land space in Singapore and the rate of waste generation has increased significantly over the years. Moreover, there is a strong dependency on natural aggregate for construction, which is imported largely from overseas. As such, the recycling of waste materials not only helps to alleviate the waste disposal problems but also provide an alternative to natural materials. This paper describes some of the waste materials that can be or has been used for road construction in Singapore. The waste materials discussed include construction and demolition (C&D) waste, asphalt pavement waste and incinerator ash that is generated from the incineration of solid waste.

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