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Dr. Dilan J. Robert
School of Engineering, RMIT University, VIC 3001, Australia

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0 unsaturated soils
0 Road pavements
0 Onshore pipelines
0 Subsea pipelines
0 Soil–structure interaction analysis

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Journal article
Published: 28 July 2021 in Journal of Constructional Steel Research
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The design of thin-walled steel plate girder cross-sections is considerably governed by the web instabilities driven by the phenomenon called shear buckling. Change of web geometry due to the partial loss of material in the form of local corrosion of web panels or the loss of mechanical properties caused by elevated temperature amplifies the shear buckling behaviour of girders leading to the loss of ultimate shear capacity significantly. Moreover, steel plate girders with low fire resistance due to their high thermal conductivity and thermal expansion are equally vulnerable to corrosion when exposed to detrimental environmental conditions. This research investigated how the standard fire resistance and elevated temperature buckling resistance of steel plate girders can be affected by the corrosion induced structural deterioration. An advanced Finite Element (FE) modelling procedure was used to evaluate the behaviour of steel plate girders shear behaviour. Some commonly encountered corrosion patterns reported in the literature were simulated. Results revealed both the position and the severity of damage is important for the fire resistance degradation resulting from the reduction in the shear capacity of thin-walled steel girders. Results were also compared with the EN 1993-1-5 design guidelines to achieve a modified formulation. This comparison revealed that depending upon the position and the extent of the corrosion level, the web contribution factor to the shear buckling resistance of a steel plate girder can fall below the Eurocode design guidelines.

ACS Style

Amila Dissanayake; Srikanth Venkatesan; Dilan Robert; Sujeeva Setunge. Damage integrated performance modelling of steel plate girders at elevated temperature. Journal of Constructional Steel Research 2021, 185, 106821 .

AMA Style

Amila Dissanayake, Srikanth Venkatesan, Dilan Robert, Sujeeva Setunge. Damage integrated performance modelling of steel plate girders at elevated temperature. Journal of Constructional Steel Research. 2021; 185 ():106821.

Chicago/Turabian Style

Amila Dissanayake; Srikanth Venkatesan; Dilan Robert; Sujeeva Setunge. 2021. "Damage integrated performance modelling of steel plate girders at elevated temperature." Journal of Constructional Steel Research 185, no. : 106821.

Journal article
Published: 19 May 2021 in Transportation Geotechnics
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Expansive soils are widespread in many parts of the world. Due to its low strength, high compressibility, and massive volumetric changes, these soils are a potential origin of damage to roads, buildings, foundations and other geo-infrastructure. Extensive research has been conducted on the utilisation of fly ash to stabilize expansive soils. This paper describes how the efficiency of fly ash based soil stabilization can be improved using secondary additives. Class F fly ash, an industrial by-product, was used as the base additive. Lime, CSA cement, enzyme and polymers were utilized as secondary additives. A series of mechanical and microscopic tests (CBR, compaction test, SEM, XRD, FTIR and TGA) was carried out on different combinations of additives. The results indicate that secondary additives can be effectively used to improve the efficiency of fly ash based soil stabilization. Soil-fly ash-lime-enzyme was identified as an optimum combination to enhance bearing capacity while soil-fly ash-lime and soil-fly ash-enzyme also showed substantial improvements in subgrade performance. Findings from laboratory investigations were verified applying into 3-D numerical modelling to evaluate the pavement performance which revealed substantial benefits of pavement thickness reduction when fly ash stablized weak soils are treated using secondary additives.

ACS Style

Hadi Karami; Jaspreet Pooni; Dilan Robert; Susanga Costa; Jie. Li; Sujeeva. Setunge. Use of secondary additives in fly ash based soil stabilization for soft subgrades. Transportation Geotechnics 2021, 29, 100585 .

AMA Style

Hadi Karami, Jaspreet Pooni, Dilan Robert, Susanga Costa, Jie. Li, Sujeeva. Setunge. Use of secondary additives in fly ash based soil stabilization for soft subgrades. Transportation Geotechnics. 2021; 29 ():100585.

Chicago/Turabian Style

Hadi Karami; Jaspreet Pooni; Dilan Robert; Susanga Costa; Jie. Li; Sujeeva. Setunge. 2021. "Use of secondary additives in fly ash based soil stabilization for soft subgrades." Transportation Geotechnics 29, no. : 100585.

Research article
Published: 16 February 2021 in International Journal of Pavement Engineering
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Civil engineers face significant challenges in the safe design and construction of durable road infrastructure in the presence of expansive soils. These problematic soils exacerbate undesirable serviceability concerns induced by pavement distress. Soil stabilisation has been recognised as a sustainable approach to alleviate the problematic nature of expansive subgrades. Road pavements constructed on top of expansive subgrade soils are generally under unsaturated conditions, where the moisture variations can significantly impact the pavement response. However, current pavement design and modelling frameworks overlook unsaturated soil behaviour by adopting simplified approaches. This study examines the hydraulic behaviour of expansive clayey soils stabilised with non-traditional and traditional chemical based additive. Tests were conducted to determine the state variation and stabilisation influence on the soil water characteristic curve using the dewpoint potentiometer for an expansive subgrade commonly found in Melbourne geology. Results show that the stabilisation has strong influence on soil hydraulic characteristics at various initial state conditions tested. Experimental data have been applied to illustrate the significance of incorporating realistic hydraulic response using a simulated practical application in road pavements. The research highlights the significance of incorporating accurate hydraulic characteristics for simulating and assessing the response of pavement constructed with stabilised unsaturated subgrade soils.

ACS Style

Jaspreet Pooni; Dilan Robert; Filippo Giustozzi; Chamila Gunasekara; Sujeeva Setunge; Srikanth Venkatesan. Hydraulic characteristics of stabilised expansive subgrade soils in road pavements. International Journal of Pavement Engineering 2021, 1 -18.

AMA Style

Jaspreet Pooni, Dilan Robert, Filippo Giustozzi, Chamila Gunasekara, Sujeeva Setunge, Srikanth Venkatesan. Hydraulic characteristics of stabilised expansive subgrade soils in road pavements. International Journal of Pavement Engineering. 2021; ():1-18.

Chicago/Turabian Style

Jaspreet Pooni; Dilan Robert; Filippo Giustozzi; Chamila Gunasekara; Sujeeva Setunge; Srikanth Venkatesan. 2021. "Hydraulic characteristics of stabilised expansive subgrade soils in road pavements." International Journal of Pavement Engineering , no. : 1-18.

Journal article
Published: 05 February 2021 in Journal of Cleaner Production
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Fly ash, despite being a suitable cement substitute, is only utilized at a low rate in engineering applications, hence not contributing to its current waste mitigation efforts. Under a five-part comprehensive testing program, this study investigated the efficiency of fly ash stabilized soil when combined with secondary additives (enzymes and lime). Part one explored the suitable fly ash and enzyme dosages. Parts two and three assessed the effect of time and lime on enzymatic fly ash stabilized soil, respectively. Part four unveiled the mechanism of stabilization by secondary additives. Part five analyzed the significance and benefits of these additives in pavement stabilization. The study found that the efficiency of fly ash stabilization can be significantly improved when combined with 1% of 1:500 diluted enzyme. Addition of 2% lime has also supplemented with improved load-bearing capacity. Benefits of this research include enhanced fly ash waste mitigation, saving natural resources used as wearing course materials, and development of an alternative solution for pavement stabilization.

ACS Style

Rintu Renjith; Dilan Robert; Sujeeva Setunge; Susanga Costa; Abbas Mohajerani. Optimization of fly ash based soil stabilization using secondary admixtures for sustainable road construction. Journal of Cleaner Production 2021, 294, 126264 .

AMA Style

Rintu Renjith, Dilan Robert, Sujeeva Setunge, Susanga Costa, Abbas Mohajerani. Optimization of fly ash based soil stabilization using secondary admixtures for sustainable road construction. Journal of Cleaner Production. 2021; 294 ():126264.

Chicago/Turabian Style

Rintu Renjith; Dilan Robert; Sujeeva Setunge; Susanga Costa; Abbas Mohajerani. 2021. "Optimization of fly ash based soil stabilization using secondary admixtures for sustainable road construction." Journal of Cleaner Production 294, no. : 126264.

Journal article
Published: 23 January 2021 in Construction and Building Materials
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No-fine concrete is a form of lightweight porous concrete, obtained by removing the sand from the normal concrete mix. The unique characteristic of high permeability of this material has mainly facilitated its applications such as in retaining walls and drainage covers for many decades. Other benefits of this form of concrete are also with low density, efficient thermal insulation and smaller drying shrinkage. Despite such benefits, its applications are limited in practice due to its smaller strength compared to convensional concrete. This study investigates the strength enhancement of No-fine concrete using waste material (i.e. coir fiber) and nano-graphene derivatives. A series of mechanical and hydraulic experiments was conducted to characterize the properties of modified No-fine concrete matrix and optimized dosages were identified to yield the expected behaviour as required by relevant standards. The mechanisms of new additives based No-fine concrete reactions were also unveiled using microscopic driven analytical techniques conducted on representative concrete specimens. Results revealed that the improved strength characteristics of No-fine concrete enhance its use as a wide application in Civil Engineering.

ACS Style

A.S. Pateriya; K. Dharavath; D.J. Robert. Enhancing the strength characteristics of No-fine concrete using wastes and nano materials. Construction and Building Materials 2021, 276, 122222 .

AMA Style

A.S. Pateriya, K. Dharavath, D.J. Robert. Enhancing the strength characteristics of No-fine concrete using wastes and nano materials. Construction and Building Materials. 2021; 276 ():122222.

Chicago/Turabian Style

A.S. Pateriya; K. Dharavath; D.J. Robert. 2021. "Enhancing the strength characteristics of No-fine concrete using wastes and nano materials." Construction and Building Materials 276, no. : 122222.

Journal article
Published: 17 December 2020 in Ocean Engineering
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Despite intensive research efforts, the accurate modelling and prediction of bridge pier scour is an outstanding challenge due to the complexities arising from the detailed interactions between granular and fluid mechanics in the riverbed. Pier scour predictions based on empirical formulas are used in conventional bridge design codes which fail to realistically account for these interactions, and thus fail to facilitate pier design optimization. A critical step towards optimal pier design is an improved physical understanding of detailed mechanisms of the scour process and the development of appropriate modelling techniques to resolve these mechanisms in engineering applications. In this study, a combination of computational fluid dynamics (CFD) and discrete element modelling (DEM) is used to improve physical understanding of the scour process, including detailed interactions between river hydrodynamics, transport of suspended particles, and granular mechanics of the riverbed. As CFD-DEM models of turbulent hydrodynamics coupled with densely packed granular assemblies are computationally expensive, it is currently not feasible to accurately model scour in macroscopic engineering applications. To address this problem, we propose a novel upscaling methodology based on highly-resolved microscale simulations that significantly reduces the computational overhead, facilitating macroscopic prediction of scour under live-bed conditions. Predictions of scour initiation, rate and extent from these microscale simulations have been validated against previously published experimental data. Results indicate that the microscale model is reasonably capable of predicting the scour initiation as well as the equilibrium scour depth. This upscaling model provides a viable methodology for the macroscopic prediction of scour in engineering applications with modest computational resources.

ACS Style

Z. Yazdanfar; Daniel Lester; Dilan Robert; Sujeeva Setunge. A novel CFD-DEM upscaling method for prediction of scour under live-bed conditions. Ocean Engineering 2020, 220, 108442 .

AMA Style

Z. Yazdanfar, Daniel Lester, Dilan Robert, Sujeeva Setunge. A novel CFD-DEM upscaling method for prediction of scour under live-bed conditions. Ocean Engineering. 2020; 220 ():108442.

Chicago/Turabian Style

Z. Yazdanfar; Daniel Lester; Dilan Robert; Sujeeva Setunge. 2020. "A novel CFD-DEM upscaling method for prediction of scour under live-bed conditions." Ocean Engineering 220, no. : 108442.

Original article
Published: 05 November 2020 in Archives of Civil and Mechanical Engineering
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The long-term impact on creep, drying shrinkage, and permeation characteristics of an innovative concrete produced with manufactured geopolymer coarse aggregate (GPA) has been investigated and compared with quarried Basalt aggregate concrete. Microstructure and pore-structure development up to 1 year were examined through scanning electron microscopy, nanoindentation, and X-ray computed tomography. Compressive strength and elastic modulus of GPA concrete varied from 34.6 to 50.8 and 18.5 to 20.5 GPa, respectively, between 28 and 365 days. The 1-year creep strain of GPA concrete was 747 microstrain while the calculated creep coefficient was 0.97, which is significantly lower than the creep coefficient predicted by AS 3600 and CEB-FIP models. Moreover, the 365-day drying shrinkage is 570 microstrain, which is also lower than the maximum permissible limit specified by AS3600. The GPA concrete displayed high water absorption, but lower air and water permeability compared to Basalt aggregate concrete. This is attributed to a porous surface layer with large number of capillaries increasing the water absorption of GPA concrete through capillary suction. The discontinuity in the pore network coupled with a condensed interfacial transition zone formed in GPA concrete could be the reason for lower permeability. Overall, the long-term performance of the GPA demonstrates a potential as a lightweight coarse aggregate for concrete, with the added advantage of reducing the environmental impact utilizing fly ash from coal-fired power generation.

ACS Style

Charitha Seneviratne; Chamila Gunasekara; David W. Law; Sujeeva Setunge; Dilan Robert. Creep, shrinkage and permeation characteristics of geopolymer aggregate concrete: long-term performance. Archives of Civil and Mechanical Engineering 2020, 20, 1 -15.

AMA Style

Charitha Seneviratne, Chamila Gunasekara, David W. Law, Sujeeva Setunge, Dilan Robert. Creep, shrinkage and permeation characteristics of geopolymer aggregate concrete: long-term performance. Archives of Civil and Mechanical Engineering. 2020; 20 (4):1-15.

Chicago/Turabian Style

Charitha Seneviratne; Chamila Gunasekara; David W. Law; Sujeeva Setunge; Dilan Robert. 2020. "Creep, shrinkage and permeation characteristics of geopolymer aggregate concrete: long-term performance." Archives of Civil and Mechanical Engineering 20, no. 4: 1-15.

Journal article
Published: 01 November 2020 in Transportation Geotechnics
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Problematic soils cause significant damage and distress in pavements from moisture induced volume and strength changes. Calcium based stabilization are well known to permanently stabilize expansive soils. Traditional calcium-based stabilizers typically include lime and cement for ground improvement of plastic clays to enhance strength. Calcium Sulfoaluminate (CSA) cement can be an effective and sustainable alternative with improved environmental considerations. The application of CSA cement to treat expansive/weak subgrade soils are limited. This research paper examines the efficiency of CSA cement compared to traditional calcium-based stabilizers in road pavements. The comprehensive laboratory study evaluates the durability of stabilized soils by assessing the mechanical performance under the effect of moisture impacts by means of investigating the bearing capacity, unconfined compressive strength (UCS) during wet-dry cycles, the resilient modulus (Mr) and UCS across practical moisture ranges and mechanical strength from vacuum saturation and moisture susceptibility testing. Results from the study reveals that the calcium-based stabilizers are effective in treating expansive soils by increasing strength across the moisture ranges tested. All stabilized soil specimens showed an increase in UCS after the completion of one wet-dry cycle and resistance to both vacuum saturation and moisture susceptibility testing. While the addition of CSA cement treatment showed considerable improvements over untreated expansive soils, it is not as effective in improving the durability performance of expansive soils compared to traditional cement and lime stabilizers under tested conditions. However, the use of CSA cement has high potential for improving weak subgrade conditions through sustainable ground stabilization.

ACS Style

J. Pooni; D. Robert; F. Giustozzi; S. Setunge; Y.M. Xie; J. Xia. Performance evaluation of calcium sulfoaluminate as an alternative stabilizer for treatment of weaker subgrades. Transportation Geotechnics 2020, 27, 100462 .

AMA Style

J. Pooni, D. Robert, F. Giustozzi, S. Setunge, Y.M. Xie, J. Xia. Performance evaluation of calcium sulfoaluminate as an alternative stabilizer for treatment of weaker subgrades. Transportation Geotechnics. 2020; 27 ():100462.

Chicago/Turabian Style

J. Pooni; D. Robert; F. Giustozzi; S. Setunge; Y.M. Xie; J. Xia. 2020. "Performance evaluation of calcium sulfoaluminate as an alternative stabilizer for treatment of weaker subgrades." Transportation Geotechnics 27, no. : 100462.

Conference paper
Published: 19 September 2020 in Lecture Notes in Civil Engineering
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Expansive clay soils are distributed worldwide, and are a source of damages to infrastructure, building foundations and roads due to its low strength, high compressibility and high level of volumetric changes. Due to excessive soil movement, uplift pressure can induce swelling pressure on foundations and shrinkage of clay can result substantial foundation settlements. In order to mitigate such adverse behaviour on structures, underlying clay needs to be improved prior to supporting the structural foundations. This study investigates the capability of enzymatic cement stabilization with recycled concrete to improve soil stability in the application to building foundations. Firstly, a series of experiments was conducted to characterise the Expansive clays obtained from the construction site. Then the experiments were performed on the basis of stabilized soils to investigate the improvement in strength and hydraulic behaviour of expansive soil. Stabilizing mix design obtained from lab tests was applied to construct building foundation on in situ clay base. Structural monitoring of the constructed foundation reveals minimal displacements during drying and wetting periods across 10 years after construction. Results from the current study will assist to derive a new standardized approach for constructing capping layer for buildings and roads using recycled materials and innovative soil stabilization methods.

ACS Style

H. Karami; D. Robert; S. Costa; F. Tostovrsnik; B. O’Donnell; S. Setunge. Construction of Working Platforms on Expansive Soils Using Recycled Concrete and Stabilizers: A Case Study. Lecture Notes in Civil Engineering 2020, 19 -30.

AMA Style

H. Karami, D. Robert, S. Costa, F. Tostovrsnik, B. O’Donnell, S. Setunge. Construction of Working Platforms on Expansive Soils Using Recycled Concrete and Stabilizers: A Case Study. Lecture Notes in Civil Engineering. 2020; ():19-30.

Chicago/Turabian Style

H. Karami; D. Robert; S. Costa; F. Tostovrsnik; B. O’Donnell; S. Setunge. 2020. "Construction of Working Platforms on Expansive Soils Using Recycled Concrete and Stabilizers: A Case Study." Lecture Notes in Civil Engineering , no. : 19-30.

Conference paper
Published: 19 September 2020 in Lecture Notes in Civil Engineering
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Production of alternative aggregates is an area of study that is contributing to achieve the goal of producing sustainable concrete. However, a thorough understanding of the material is required prior to its application in construction for sustainable practice. While laboratory experiments can facilitate the understanding of new material, it is always challenging to use lab tests for damaged response evaluation and in particular failure assessment of its applications. State-of-art numerical modeling approaches with advanced material modeling can facilitate minimizing those challenges when they are calibrated/benchmarked using measured data. This study investigates for a suitable modeling approach to capture the damage response of a new material (i.e. Geopolymer) based coarse aggregate (GPA) concrete. Modeling was conducted by adopting the standard continuum modelling method. Unconfined strength test was simulated by considering Concrete Damage Plasticity (CDP) model in an explicit platform. Laboratory experiments such as stress-strain tests and compressive strength tests were also performed to calibrate and benchmark the results from the numerical model. The effect of mesh sensitivity has been identified in the outcome of damage prediction for GPA concrete. Results from the verified numerical models have been related to assess the permeability degradation of GPA. Outcomes from the study are important to predict structural/damage response using the new Geopolymer based aggregate concrete and facilitate the evaluation of structural response under loading.

ACS Style

C. Seneviratne; D. Robert; C. Gunasekara; M. Wimalasiri; D. Law; S. Setunge. Damage Assessment of Geopolymer Aggregate Concrete Using Numerical Modeling. Lecture Notes in Civil Engineering 2020, 31 -46.

AMA Style

C. Seneviratne, D. Robert, C. Gunasekara, M. Wimalasiri, D. Law, S. Setunge. Damage Assessment of Geopolymer Aggregate Concrete Using Numerical Modeling. Lecture Notes in Civil Engineering. 2020; ():31-46.

Chicago/Turabian Style

C. Seneviratne; D. Robert; C. Gunasekara; M. Wimalasiri; D. Law; S. Setunge. 2020. "Damage Assessment of Geopolymer Aggregate Concrete Using Numerical Modeling." Lecture Notes in Civil Engineering , no. : 31-46.

Journal article
Published: 02 September 2020 in Construction and Building Materials
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Expansive soils are a common problem to overlying geotechnical structures risking for distress and damage caused by moisture induced ground movements. Calcium-based stabilization is readily adopted to improve and enhance the problematic expansive subgrade increasing strength and the volume change behaviour. For ground improvement, the use of lime and Ordinary Portland Cement (OPC) to treat expansive soil has been in common practice; however, Calcium Sulfoaluminate (CSA) cement can be an effective alternative due to the reduced environmental impact. To date, limited literature surrounds the understanding of CSA cement in expansive soil, but largely focussed its applications on concrete infrastructure. This paper investigates the stabilization mechanism of CSA treated expansive soils by identifying the major hydration products and microstructural characteristics with respect to CSA cement dosage and curing rate. The study reveals CSA cement stabilization directly affects mechanical properties and microstructural characteristics due to three key phases of cationic exchange, flocculation and agglomeration between the clay sheets and cementitious hydration. The addition of CSA cement in the ground stabilization serves to shift towards a sustainable approach in reducing the carbon impact of traditional stabilization techniques.

ACS Style

J. Pooni; D. Robert; F. Giustozzi; S. Setunge; Y.M. Xie; J. Xia. Novel use of calcium sulfoaluminate (CSA) cement for treating problematic soils. Construction and Building Materials 2020, 260, 120433 .

AMA Style

J. Pooni, D. Robert, F. Giustozzi, S. Setunge, Y.M. Xie, J. Xia. Novel use of calcium sulfoaluminate (CSA) cement for treating problematic soils. Construction and Building Materials. 2020; 260 ():120433.

Chicago/Turabian Style

J. Pooni; D. Robert; F. Giustozzi; S. Setunge; Y.M. Xie; J. Xia. 2020. "Novel use of calcium sulfoaluminate (CSA) cement for treating problematic soils." Construction and Building Materials 260, no. : 120433.

Journal article
Published: 01 September 2020 in Journal of Materials in Civil Engineering
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Permeability of concrete is usually measured in laboratory conditions without loading, which can be completely different from that in service. This paper presents a new method to determine the permeability coefficient of concrete under applied loading, considering concrete plasticity. A dissipated energy–based approach is proposed to determine the damage variables for the concrete damage plasticity model. The developed method is verified with experimental results, after which a parametric study is conducted to identify the factors that affect the permeability degradation. It is found in the paper that the applied load is the governing factor for permeability degradation of concrete, and that the permeability degradation is influenced by grade of concrete, aggregate size, thickness of the interfacial transition zone, and the shape of aggregates. The significance of the developed method is that it can determine the permeability coefficient of concrete as a function of time with various constituent combinations and under any applied stresses, which would otherwise be impractical with experimental techniques.

ACS Style

Manuka Wimalasiri; Dilan Robert; Chun-Qing Li. Permeability Degradation of Stressed Concrete Considering Concrete Plasticity. Journal of Materials in Civil Engineering 2020, 32, 04020265 .

AMA Style

Manuka Wimalasiri, Dilan Robert, Chun-Qing Li. Permeability Degradation of Stressed Concrete Considering Concrete Plasticity. Journal of Materials in Civil Engineering. 2020; 32 (9):04020265.

Chicago/Turabian Style

Manuka Wimalasiri; Dilan Robert; Chun-Qing Li. 2020. "Permeability Degradation of Stressed Concrete Considering Concrete Plasticity." Journal of Materials in Civil Engineering 32, no. 9: 04020265.

Journal article
Published: 06 July 2020 in International Journal of Pressure Vessels and Piping
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Corrosion induced degradation of fracture toughness in buried cast iron pipes is a serious concern for structural integrity and smooth operation of buried pipes. External corrosion of pipes is fundamentally governed by the corrosivity of soil which may vary depending on the type of soil and its specific properties. While the corrosion assessments of pipes buried in soil can provide realistic behaviour, the investigations of pipe corrosion in simulated soil solutions are becoming popular due to simplicity. Limited studies are reported in the literature using simulated soil solution for determining the effect of corrosion on the fracture toughness of cast iron specimens. However, it is important to evaluate the outcomes based on the solutions benchmarking against the corrosion from the realistic soil environment. This study investigates the corrosion of cast iron specimens in both the acidic soils and the simulated soil solutions of the same varying pH for 365 days. The fracture toughness testing of the corroded specimens taken out from both the real and simulated soil solutions was performed at 180 and 365 days, respectively. The fracture toughness (KQ) values of the corroded specimens of the two soil mediums were compared and correlated statistically. Moreover, relations for the variation in KQ of specimens as a function of corrosion rates, and pH with time were developed for soil and simulated soil solution. The findings of this research have practical applications for the predictions of the service life of buried cast iron pipes.

ACS Style

Muhammad Wasim; Chun-Qing Li; Dilan Robert; Mojtaba Mahmoodian. Fracture toughness degradation of cast iron due to corrosive mediums. International Journal of Pressure Vessels and Piping 2020, 186, 104151 .

AMA Style

Muhammad Wasim, Chun-Qing Li, Dilan Robert, Mojtaba Mahmoodian. Fracture toughness degradation of cast iron due to corrosive mediums. International Journal of Pressure Vessels and Piping. 2020; 186 ():104151.

Chicago/Turabian Style

Muhammad Wasim; Chun-Qing Li; Dilan Robert; Mojtaba Mahmoodian. 2020. "Fracture toughness degradation of cast iron due to corrosive mediums." International Journal of Pressure Vessels and Piping 186, no. : 104151.

Journal article
Published: 01 July 2020 in Journal of Materials in Civil Engineering
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There has been limited research in the past on the effect of varying soil’s acidity measured as pH and saturation measured as moisture content on the fracture toughness of buried cast iron as per comprehensive literature review. This paper presents findings obtained from a long-term test designed to investigate the combined effect of varying levels of soil’s acidity and saturation on the fracture toughness of buried cast iron over time. Relations for the change in candidature fracture toughness of the corroded cast iron over time as a function of soil’s pH, moisture content, and corrosion pit depth are developed. Moreover, a relation correlating the change in microstructure and the fracture toughness of the corroded cast iron is also developed. The significance of the current paper is that it reports that soil’s corrosivity induces a change in the microstructure and composition of cast iron, which consequently affects the fracture toughness of the corroded cast iron.

ACS Style

Muhammad Wasim; Chun-Qing Li; Dilan Robert; Mojtaba Mahmoodian. Effect of Soil’s Acidity and Saturation on Degradation of Fracture Toughness of Buried Cast Iron. Journal of Materials in Civil Engineering 2020, 32, 04020180 .

AMA Style

Muhammad Wasim, Chun-Qing Li, Dilan Robert, Mojtaba Mahmoodian. Effect of Soil’s Acidity and Saturation on Degradation of Fracture Toughness of Buried Cast Iron. Journal of Materials in Civil Engineering. 2020; 32 (7):04020180.

Chicago/Turabian Style

Muhammad Wasim; Chun-Qing Li; Dilan Robert; Mojtaba Mahmoodian. 2020. "Effect of Soil’s Acidity and Saturation on Degradation of Fracture Toughness of Buried Cast Iron." Journal of Materials in Civil Engineering 32, no. 7: 04020180.

Articles
Published: 22 May 2020 in International Journal of Pavement Engineering
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Unsealed roads are an important asset providing the necessary connections between regional and metropolitan regimes of a country. However, these roads are affected by severe moisture fluctuations and recurring traffic loads that result in excessive maintenance. Unsealed road pavements are generally partially saturated during their service life, resulting in distinct volume and strength changes subjected to saturation changes. This paper investigates the capability of a novel stabiliser in reducing the adverse impact from moisture fluctuations and dynamic traffic loads on unsealed road pavements using an experimental and modelling approach. Firstly, a series of physical and mechanical tests were conducted on enzyme stabilised soil to explore its response under various saturations and its ability to suppress volume change. The application of subgrade stabilisation was then simulated using a verified modelling approach to assess the effectiveness of the novel stabilisation methodology for constructing unsealed road pavements. Finally, an analytical model was proposed to predict the performance of unsealed roads constructed on stabilised expansive subgrades subjected to loading and moisture cycles. The research highlights the importance of considering the effect of moisture fluctuations in pavement design and the possibility of adopting soil stabilisation for improved performance of unsealed roads constructed on expansive subgrade soil.

ACS Style

Jaspreet Pooni; Dilan Robert; Filippo Giustozzi; Sujeeva Setunge; Srikanth Venkatesan. Stabilisation of expansive soils subjected to moisture fluctuations in unsealed road pavements. International Journal of Pavement Engineering 2020, 1 -13.

AMA Style

Jaspreet Pooni, Dilan Robert, Filippo Giustozzi, Sujeeva Setunge, Srikanth Venkatesan. Stabilisation of expansive soils subjected to moisture fluctuations in unsealed road pavements. International Journal of Pavement Engineering. 2020; ():1-13.

Chicago/Turabian Style

Jaspreet Pooni; Dilan Robert; Filippo Giustozzi; Sujeeva Setunge; Srikanth Venkatesan. 2020. "Stabilisation of expansive soils subjected to moisture fluctuations in unsealed road pavements." International Journal of Pavement Engineering , no. : 1-13.

Journal article
Published: 01 May 2020 in Journal of Materials in Civil Engineering
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Enzyme-based soil stabilizers have been successfully used in ground applications for the last 30 years. However, the successful application of a given enzyme-based additive is case specific and depends on soil type, soil condition, and operational loads. As a result, contractors incur a substantial cost in terms of time and money for preliminary lab tests, which may determine the suitable mix proportions to utilize in the field application. A sound understanding of the stabilization mechanism of these additives can minimize these costs and yield optimum benefits from the stabilization process. This paper investigates the stabilization effects of a novel enzyme-based additive, commercially known as Eko Soil, that is being applied to construct unpaved roads in Australia and worldwide. The aim of this research is to identify the optimized mix proportions of the additive by unveiling its mechanism of stabilization for a fine-grained field soil, which is dominant in Victoria, Australia. A series of experiments were conducted under a 4-stage test program that included macroscale mechanical tests and microscale imaging tests to unveil stabilization effects and the mechanism of stabilization. The identified mechanism has facilitated enhancement in the efficiency of enzyme-based soil stabilization significantly compared to the strength of nonstabilized soil. The research will substantially benefit the road construction industry by not only replacing traditional construction methods with economical/reliable approaches, but also providing insight on the optimum additive amount required to stabilize road pavements based on this stabilization mechanism.

ACS Style

Rintu Renjith; Dilan J. Robert; Chamila Gunasekara; Sujeeva Setunge; Brian O’Donnell. Optimization of Enzyme-Based Soil Stabilization. Journal of Materials in Civil Engineering 2020, 32, 04020091 .

AMA Style

Rintu Renjith, Dilan J. Robert, Chamila Gunasekara, Sujeeva Setunge, Brian O’Donnell. Optimization of Enzyme-Based Soil Stabilization. Journal of Materials in Civil Engineering. 2020; 32 (5):04020091.

Chicago/Turabian Style

Rintu Renjith; Dilan J. Robert; Chamila Gunasekara; Sujeeva Setunge; Brian O’Donnell. 2020. "Optimization of Enzyme-Based Soil Stabilization." Journal of Materials in Civil Engineering 32, no. 5: 04020091.

Journal article
Published: 18 December 2019 in Soil Dynamics and Earthquake Engineering
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Offshore pipelines are increasingly being adopted at elevated temperatures and pressures as more petroleum deposits are explored deep offshore. These extra-long pipelines are subjected to frequent heating and cooling cycles that can lead to ‘pipeline walking’, resulting in serviceability failures during service life. Understanding the behaviour of the shearing zone beneath pipelines provides essential information to support reliable predictions of pipe axial-soil interaction. This study examines the cyclic shearing response of soil underneath axially moving pipelines using large-scale experiments and cyclic direct simple shear tests. Large-scale pipe-soil tests were first conducted to understand the shearing mechanism and zone of shearing influence of the soft clay underneath the pipeline. Having characterised the shearing mechanism using pipe-soil tests, cyclic direct simple shear tests were then performed for further characterization of the residual shearing resistance under various practical drainage conditions of pipe-soil interaction. The results of the simple shear tests show reliable prediction of axial walking response compared with large-scale test data. The results of the present study were also used to identify drainage limits and residual resistance using dimensionless charts which can contribute to the design practice of offshore pipelines when considering on-bottom stability in axial direction.

ACS Style

D.J. Robert; Yang Ao; M. Senthilkumar; Jayantha Kodikara; P. Rajeev. Cyclic loading response of offshore pipelines using simple shear tests. Soil Dynamics and Earthquake Engineering 2019, 130, 105991 .

AMA Style

D.J. Robert, Yang Ao, M. Senthilkumar, Jayantha Kodikara, P. Rajeev. Cyclic loading response of offshore pipelines using simple shear tests. Soil Dynamics and Earthquake Engineering. 2019; 130 ():105991.

Chicago/Turabian Style

D.J. Robert; Yang Ao; M. Senthilkumar; Jayantha Kodikara; P. Rajeev. 2019. "Cyclic loading response of offshore pipelines using simple shear tests." Soil Dynamics and Earthquake Engineering 130, no. : 105991.

Journal article
Published: 09 October 2019 in Journal of Pressure Vessel Technology
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Pipelines are used to provide variety of services in modern community and have grown rapidly in past few decades due to growing socio-economic requirements. Most of the water mains are buried in shallow depths where the soil is partially saturated with significant spatial and temporal variations. Even though the behavior of buried pipes in such unsaturated soil condition is substantially different when compared to dry or fully saturated soil, the effect of soil saturations is overlooked in the current pipe stress prediction methods, leading to unrealistic predictions of the pipe stresses. In this study, three-dimensional (3D) finite element (FE) method was employed with advanced constitutive soil models to analyze the behavior of pipes buried in unsaturated soil condition. Having validated the FE model using reported field test data, an analytical model was proposed to predict the maximum stress in buried pipes considering soil saturation effect using a series of 3D FE analyses. Results from the FE analyses reveal that the maximum pipe stress can be significantly different when soil is in unsaturated condition when compared to dry condition. The proposed formula shows a good agreement with the field data and FE results, so that the expression can be used in the prediction of maximum pipe stress when they are buried under realistic (i.e., nondry) soil conditions.

ACS Style

Chamal Randeniya; Dilan Robert; Chun-Qing Li. Stress Prediction of Buried Pipes Subjected to Operational Loadings in Unsaturated Soils. Journal of Pressure Vessel Technology 2019, 141, 1 .

AMA Style

Chamal Randeniya, Dilan Robert, Chun-Qing Li. Stress Prediction of Buried Pipes Subjected to Operational Loadings in Unsaturated Soils. Journal of Pressure Vessel Technology. 2019; 141 (6):1.

Chicago/Turabian Style

Chamal Randeniya; Dilan Robert; Chun-Qing Li. 2019. "Stress Prediction of Buried Pipes Subjected to Operational Loadings in Unsaturated Soils." Journal of Pressure Vessel Technology 141, no. 6: 1.

Conference paper
Published: 04 September 2019 in Proceedings of EECE 2020
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Unsealed road infrastructure makes up about two-thirds of the multi-billion dollar asset, playing an important role in transportation, and it is vital in countries development. Its importance is further highlighted by the many kilometres of roads worldwide. These roads are inherently exposed to external loading from increased recurring traffic and geohazards, which can lead to failures, posing great safety concerns. Failures can further be triggered by moisture degradation when unsealed roads are constructed with reactive soils. Soil stabilization has been widely identified as a cost effective solution for pavement degradation in several past research studies. Road pavement materials are partially saturated during their service life, and exhibit distinct volume and strength changes as a result. A change in the degree of saturation can cause significant shrink and swell deformations, and shear strength changes. However, the current assessment and design of road pavements using established standards assume linear material response to static loading and two-dimensional geometric idealization with no provisions on subgrade moisture fluctuations. The current research investigates the effect of moisture degradation in stabilized unsealed road pavements using laboratory experiments and numerical modelling. Firstly, a series of mechanical tests were conducted to assess the volume change and strength behaviour of stabilized soil. Then finite element analyses were performed to investigate the performance of road pavements subjected to changes in the degree of saturation. Preliminary results showed that the stabilized road pavements using bio-enzymatic additives are effective in reducing the road deformations and the developed models are capable of capturing realistic swelling/shrinkage of road pavement under operational and environmental loads. The study revealed the importance of adopting non-linear material characterization and modelling for realistic assessment of soil stabilization when exposed to moisture damage.

ACS Style

J. Singh; D. Robert; F. Giustozzi; S. Setunge; B. O’Donnell. Prediction of Moisture Degradation in Enzyme-Stabilized Unsealed Road Pavements. Proceedings of EECE 2020 2019, 623 -634.

AMA Style

J. Singh, D. Robert, F. Giustozzi, S. Setunge, B. O’Donnell. Prediction of Moisture Degradation in Enzyme-Stabilized Unsealed Road Pavements. Proceedings of EECE 2020. 2019; ():623-634.

Chicago/Turabian Style

J. Singh; D. Robert; F. Giustozzi; S. Setunge; B. O’Donnell. 2019. "Prediction of Moisture Degradation in Enzyme-Stabilized Unsealed Road Pavements." Proceedings of EECE 2020 , no. : 623-634.

Journal article
Published: 01 September 2019 in Journal of Materials in Civil Engineering
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Corrosive soil has been reported to be a prominent cause of the failure of buried cast iron pipes. Little research has been conducted with a specific focus on the effects of soil acidity and saturation on the corrosion of buried cast iron and subsequent microstructural changes in the corroded cast iron. This paper presents results produced from a comprehensive experimental program designed to determine the coupled effect of soil acidity and saturation on corrosion and subsequent changes in the microstructure of cast iron buried in soil. Relations between corrosion and subsequent microstructural changes in corroded cast iron with affecting factors and time were developed. The study determined that soil with low acidity (pH 5) and high saturation (80%) was the most corrosion-prone environment among the various soil conditions investigated and that corrosion can cause significant changes in the microstructure of cast iron. The significance of these findings is that any changes in the microstructure of cast iron can directly affect the mechanical properties of the corroded cast iron, which are directly related to the service life of corrosion-affected cast iron pipes.

ACS Style

Muhammad Wasim; Chun-Qing Li; Mojtaba Mahmoodian; Dilan Robert. Quantitative Study of Coupled Effect of Soil Acidity and Saturation on Corrosion and Microstructure of Buried Cast Iron. Journal of Materials in Civil Engineering 2019, 31, 04019206 .

AMA Style

Muhammad Wasim, Chun-Qing Li, Mojtaba Mahmoodian, Dilan Robert. Quantitative Study of Coupled Effect of Soil Acidity and Saturation on Corrosion and Microstructure of Buried Cast Iron. Journal of Materials in Civil Engineering. 2019; 31 (9):04019206.

Chicago/Turabian Style

Muhammad Wasim; Chun-Qing Li; Mojtaba Mahmoodian; Dilan Robert. 2019. "Quantitative Study of Coupled Effect of Soil Acidity and Saturation on Corrosion and Microstructure of Buried Cast Iron." Journal of Materials in Civil Engineering 31, no. 9: 04019206.