Oedometric study of dredged marine soils admixed with sand for settlement reduction

Dredged marine soils (DMS) can be reused as fill materials for land reclamation project other than dump back to the open sea. However, in Malaysia, dredged marine soils were considered as a geowaste because of it has poor engineering properties. In the present study, dredged marine soils were excavated from the dredging works near the jetty of Kuala Perlis, Malaysia. To investigate the settlement reduction of DMS, a sand-mixed was used in this study and these results were compared with natural DMS (without sand). Oedometer test were conducted to calculate the consolidation properties of DMS and k-value can be obtained from the test. The test results showed that the dissipation of water from soils occurs faster in the sand-mixed compare to the control sample (without sand) due to the drainage path that have been reduced (two-way drainage)

Shear resistance of rubber-ballast composites in simulated water and acid soaked conditions

Ballast is one of the main structures for the railway tracks. It can resist the lateral movement under dynamic loading transferred by the passing trains with repeatedly. Under some circumstances, ballast can suffer degradation or breakdown due to the repeated loading and maintenance. Ballast is easily exposed to the weather because it is laid on the track. Acid rain affects the performance of the railway track near the industrial and urban area. As a result, it starts to foul and the small chips from ballast filled the void, as well as reduce the shear strength of ballast particles. This situation can contribute into the increasing of maintenance frequency and costing. This paper examines the potential of rubber inclusions in increasing the shear resistance of rubber-ballast composites in simulated water and acid soaked conditions with several configuration. This lab-based exploratory work is only static load simulation in conventional shear box setup measuring 60 mm × 60 mm. The aggregates size is 10 times smaller than actual size of ballast. In order to identify the shear resistance deterioration of rubber-aggregates mixture under poor drainage conditions by soaked a batch of aggregates in water and acid solution for 2 weeks to simulate accelerated weathering effects. The shear resistance did not rise dramatically with the rubber reinforcement. This susceptible shear strain plots indicate ductile behaviour on the aggregates-rubber composites. This is evident by the linear rise of shear stress with strain up to approximately 10% for the control samples (CS) until it reaches a constant value. Note that all the specimens including CS are in a loose state during the testing because there were no tamping been applied on the samples. Overall the circular patch (CP) specimen was the most favourable than the other configurations. Both mechanisms contributed to the reduced overall subsistence, accompanied by an increase in the shear resistance. The inclusion of rubber elements apparently prevented the dilation of the granular material when approaching the shear failure and the reducing the settlement

Shear resistance improvement of oil-contaminated ballast layer with rubber shred inclusions

Railway ballast, which form an integral part of rail tracks, is highly susceptible to subsistence due to both vibration transmitted by the passing trains, as well as the breakage of ballasts with repeated impact. The resulting subsistence necessitates regular monitoring and maintenance, involving cost- and time- consuming remedial actions, such as stone-blowing and ballast renewal. Measures to minimize the wear and tear effect are therefore desirable to prolong the lifespan of the ballast layer. It is even more critical when the ballast is contaminated with oil and grease from braking wheels and leakages. This paper describes the inclusion of rubber shreds (≤10 mm in length, 1.5 mm thick) derived from the inner tubes of motorcycle tyres in oil-contaminated ballast layer for shear resistance improvement. The tests are mainly carried out in a standard direct shear test setup, i.e. shear box measuring 60 mm x 60 mm. Granitic stones of suitable sizes were sieved and used as representative samples of typical ballast. The samples were soaked in lubricant oil for 14 days to simulate the contamination. The direct shear test results indicated rubber shreds inclusion could effectively improve the shear resistance of ballast and expedient in deformation control with increased ductility of the composites. This could potentially improve absorption of impact, hence reduction of breakages of the ballasts. Clearly both mechanisms contribute to the overall reduced subsistence, accompanied by an increase in the shear resistance. However, further investigations in a dynamic test setup are necessary for verifications prior to field implementation

Shear resistance of rubber-ballast composites in simulated water and acid soaked conditions

Ballast is one of the main structures for the railway tracks. It can resist the lateral movement under dynamic loading transferred by the passing trains with repeatedly. Under some circumstances, ballast can suffer degradation or breakdown due to the repeated loading and maintenance. Ballast is easily exposed to the weather because it is laid on the track. Acid rain affects the performance of the railway track near the industrial and urban area. As a result, it starts to foul and the small chips from ballast filled the void, as well as reduce the shear strength of ballast particles. This situation can contribute into the increasing of maintenance frequency and costing. This paper examines the potential of rubber inclusions in increasing the shear resistance of rubber-ballast composites in simulated water and acid soaked conditions with several configuration. This lab-based exploratory work is only static load simulation in conventional shear box setup measuring 60 mm × 60 mm. The aggregates size is 10 times smaller than actual size of ballast. In order to identify the shear resistance deterioration of rubber-aggregates mixture under poor drainage conditions by soaked a batch of aggregates in water and acid solution for 2 weeks to simulate accelerated weathering effects. The shear resistance did not rise dramatically with the rubber reinforcement. This susceptible shear strain plots indicate ductile behaviour on the aggregates-rubber composites. This is evident by the linear rise of shear stress with strain up to approximately 10% for the control samples (CS) until it reaches a constant value. Note that all the specimens including CS are in a loose state during the testing because there were no tamping been applied on the samples. Overall the circular patch (CP) specimen was the most favourable than the other configurations. Both mechanisms contributed to the reduced overall subsistence, accompanied by an increase in the shear resistance. The inclusion of rubber elements apparently prevented the dilation of the granular material when approaching the shear failure and the reducing the settlement

Oedometric study of dredged marine soils admixed with sand for settlement reduction

Dredged marine soils (DMS) can be reused as fill materials for land reclamation project other than dump back to the open sea. However, in Malaysia, dredged marine soils were considered as a geowaste because of it has poor engineering properties. In the present study, dredged marine soils were excavated from the dredging works near the jetty of Kuala Perlis, Malaysia. To investigate the settlement reduction of DMS, a sand-mixed was used in this study and these results were compared with natural DMS (without sand). Oedometer test were conducted to calculate the consolidation properties of DMS and k-value can be obtained from the test. The test results showed that the dissipation of water from soils occurs faster in the sand-mixed compare to the control sample (without sand) due to the drainage path that have been reduced (two-way drainage)

Indicators for measuring satisfaction towards design quality of buildings

Design quality is an important component in measuring satisfaction towards total product quality (TPQ) of buildings, the product of construction projects. Design Quality Indicator (DQI), developed by the Construction Industry Council (CIC) in the UK looking at three quality fields, i.e. functionality, build quality, and impact of building in measuring the quality of design embodied in the buildings through feedback and perceptions of all stakeholders involved in the production and use of buildings. Design quality is always a major concern in the Malaysian construction industry. With inspiration from this DQI, this study was carried out to identify indicators for measuring the satisfaction towards design quality of buildings and to evaluate the suitability of the indicators for application in the context of Malaysian construction industry. Through literature survey, 32 indicators of design quality were identified and grouped into the three design quality fields. A questionnaire survey was carried out among Malaysian construction professionals (architects, engineers, quantity surveyors, contractors and developers) to assess the identified design quality indicators in terms of their relevance and significance in the context of construction industry in Malaysia. The survey reveals that access, natural lighting, access and use, structure element, landscape, finishes, location, external environment, urban and social integration and noise are among the design quality indicators that were perceived as the most important to be looked at. In overall, all the indicators are relevant for adoption in the Malaysian construction industry to measure the satisfaction towards design quality of buildings