Dr Gowripalan obtained his PhD degree from the University of Leeds, UK in 1987. He worked at the University of Leeds for 3 years before coming to Australia. He has worked at the University of New South Wales, Australia from 1990-2012. He has visited University of Cambridge UK, Georgia Institute of Technology USA (1996), University of British Columbia Canada (2006) and many other universities in America, Europe and Asia. He has visited more than 40 countries and published more than 100 technical papers in his area of specialisation. He has supervised and graduated 7 PhD and many Masters students over the past 20 years. He has served in 4 Standards Australia Committees and many International Scientific Committees. He has been a member of Institution of Engineers (Australia), Institution of Civil Engineers (UK), Institution of Structural Engineers (UK), American Society of Civil Engineers (USA). He has been a reviewer of technical papers for Journals such as ACI Materials, ACI Structures, Cement and Concrete Composites, Cement and Concrete Research and Computers and Concrete. He has also built bridges in Europe, Australia and in Asia. He has also been a Director of two Organisations.
Currently he is attached to University of Technology Sydney and is a Chief Investigator of projects related to Alkali-Silica Reaction, under ARC ITRH Nanoscience & Construction Materials.
Can supervise: YES
Shakor, P, Nejadi, S, Sutjipto, S, Paul, G & Gowripalan, N 2020, 'Effects of deposition velocity in the presence/absence of E6-glass fibre on extrusion-based 3D printed mortar', Additive Manufacturing, vol. 32.View/Download from: Publisher's site
© 2020 Additive Manufacturing (AM) technologies are widely used in various fields of industry and research. Continual research has enabled AM technologies to be considered as a feasible substitute for certain applications in the construction industry, particularly given the advances in the use of glass fibre reinforced mortar. An investigation of the resulting mechanical properties of various mortar mixes extruded using a robotic arm is presented. The nozzle paths were projected via 'spline' interpolation to obtain the desired trajectory and deposition velocity in the reference frame of the manipulator. Along each path, various mortar mixes, with and without chopped glass fibre, were deposited at different velocities. Tests were conducted to determine their mechanical performance when incorporated in printed structures with different layers (1, 2, 4 and 6 layers). The results are compared with those of conventional cast-in-place mortar. In this study, the mixes consist of ordinary Portland cement, fine sand, chopped glass fibres (6 mm) and chemical admixtures, which are used to print prismatic- and cubic-shaped specimens. Mechanical strength tests were performed on the printed specimens to evaluate the behaviour of the materials in the presence and absence of glass fibre. Robot end-effector velocity tests were performed to examine the printability and extrudability of the mortar mixes. Finally, horizontal and vertical line printing tests were used to determine the workability, buildability and uniformity of the mortar mix and to monitor the fibre flow directions in the printed specimens. The results show that printed specimens with glass fibre have enhanced compressive strength compared with specimens without glass fibre.
Alkali silica reaction (ASR) in concrete is a deleterious reaction which occurs due to the reaction between alkalis in the pore solution and reactive forms of silica found in some aggregates. ASR results in expansion and cracking which reduce the mechanical properties of the concrete. An ultra-accelerated autoclave test method has been used to test concrete prisms with and without alkali boosting. In this method, expansion and deterioration caused by ASR in concrete was investigated using an autoclave to simulate long-term deterioration. Test parameters such as temperature, pressure, duration of autoclaving and alkali boosting were investigated. Results obtained within a short period, clearly show large expansions and deterioration levels for concrete made with reactive aggregates.
Evaluation of reduction in modulus of elasticity of concrete undergoing alkali silica reaction is carried out using an artificial neural network
Nguyen, TN, Yu, Y, Li, J, Gowripalan, N & Sirivivatnanon, V 2019, 'Elastic modulus of ASR-affected concrete: An evaluation using Artificial Neural Network', Computers and Concrete, vol. 24, no. 6, pp. 541-553.View/Download from: Publisher's site
Copyright © 2019 Techno-Press, Ltd. Alkali-silica reaction (ASR) in concrete can induce degradation in its mechanical properties, leading to compromised serviceability and even loss in load capacity of concrete structures. Compared to other properties, ASR often affects the modulus of elasticity more significantly. Several empirical models have thus been established to estimate elastic modulus reduction based on the ASR expansion only for condition assessment and capacity evaluation of the distressed structures. However, it has been observed from experimental studies in the literature that for any given level of ASR expansion, there are significant variations on the measured modulus of elasticity. In fact, many other factors, such as cement content, reactive aggregate type, exposure condition, additional alkali and concrete strength, have been commonly known in contribution to changes of concrete elastic modulus due to ASR. In this study, an artificial intelligent model using artificial neural network (ANN) is proposed for the first time to provide an innovative approach for evaluation of the elastic modulus of ASR-affected concrete, which is able to take into account contribution of several influence factors. By intelligently fusing multiple information, the proposed ANN model can provide an accurate estimation of the modulus of elasticity, which shows a significant improvement from empirical based models used in current practice. The results also indicate that expansion due to ASR is not the only factor contributing to the stiffness change, and various factors have to be included during the evaluation.
Vu, T, Gowripalan, N, De Silva, P, Kidd, P & Sirivivatnanon, V 2019, 'Influence of curing and retarder on early-age properties of powder geopolymer concrete', Concrete in Australia, vol. Volume 45, no. No 2, pp. 41-46.
The effect of different curing conditions and the addition of a retarder on flow characteristics, setting time and strength development of a powder form of geopolymer is reported.
Vu, TH & Gowripalan, N 2018, 'Mechanism of heavy metal immobilisation using geopolymerisation techniques - A review', Journal of Advanced Concrete Technology, vol. Vol 16, no. 3, pp. 124-135.View/Download from: Publisher's site
Every year, substantial amount of waste materials containing toxic substances is produced throughout the world, which causes serious damage to the environment and poses threat to human health. Among available techniques of immobilisation of toxic elements in harmful by-products, geopolymerisation is considered as an effective approach to deal with many environmental issues. Geopolymer binders have long been recognised to have great potential in immobilisation of hazardous wastes due to its advantages over Portland cement based binders. A profound knowledge of how hazardous elements are immobilised by geopolymer binders is necessary for achieving effective waste management strategies. This paper provides some important aspects of geopolymer materials regarding the immobilisation mechanisms and factors influencing the immobilisation efficiency, which are necessary to carry out further research on addressing the hazardous waste immobilisation.
Erkmen, RE, Gowripalan, N & Sirivivatnanon, V 2017, 'Elasto-plastic damage modelling of beams and columns with mechanical degradation', COMPUTERS AND CONCRETE, vol. 19, no. 3, pp. 315-323.View/Download from: Publisher's site
Childs, P, Wong, ACL, Gowripalan, N & Peng, GD 2007, 'Measurement of the coefficient of thermal expansion of ultra-high strength cementitious composites using fibre optic sensors', CEMENT AND CONCRETE RESEARCH, vol. 37, no. 5, pp. 789-795.View/Download from: Publisher's site
Wong, ACL, Childs, PA, Berndt, R, Macken, T, Peng, G-D & Gowripalan, N 2007, 'Simultaneous measurement of shrinkage and temperature of reactive powder concrete at early-age using fibre Bragg grating sensors', CEMENT & CONCRETE COMPOSITES, vol. 29, no. 6, pp. 490-497.View/Download from: Publisher's site
Wong, ACL, Childs, PA, Terry, W, Gowripalan, N & Peng, G-D 2007, 'Experimental investigation of drying shrinkage and creep of concrete using fibre-optic sensors', ADVANCES IN STRUCTURAL ENGINEERING, vol. 10, no. 3, pp. 219-228.View/Download from: Publisher's site
Han, CG, Hwang, YS, Yang, SH & Gowripalan, N 2005, 'Performance of spalling resistance of high performance concrete with polypropylene fiber contents and lateral confinement', CEMENT AND CONCRETE RESEARCH, vol. 35, no. 9, pp. 1747-1753.View/Download from: Publisher's site
Hamidah, HM, Gowripalan, N & Fadhil, NM 2001, 'Absorption of aramid prestressing rods in aggressive solutions', JOURNAL OF COMPOSITES FOR CONSTRUCTION, vol. 5, no. 4, pp. 254-257.View/Download from: Publisher's site
Lim, CC, Gowripalan, N & Sirivivatnanon, V 2000, 'Microcracking and chloride permeability of concrete under uniaxial compression', CEMENT & CONCRETE COMPOSITES, vol. 22, no. 5, pp. 353-360.View/Download from: Publisher's site
Gowripalan, N & Mohamed, HM 1998, 'Chloride-ion induced corrosion of galvanized and ordinary steel reinforcement in high-performance concrete', CEMENT AND CONCRETE RESEARCH, vol. 28, no. 8, pp. 1119-1131.View/Download from: Publisher's site
Gowripalan, N, Cabrera, JG, Cusens, AR & Wainwright, PJ 1990, 'Effect of curing on durability', Concrete International, vol. 12, no. 2, pp. 47-54.
The durability of concrete structures is greatly influenced by the curing of the concrete. Inadequate curing can result in a very weak and porous material near the surface of the concrete that is vulnerable to ingress of various harmful substances from the environment. A review is presented of the effects of methods and duration of curing on concrete properties with respect to permeability, porosity, and water absorption. Results obtained from mortar specimens that were cured using chemical membranes are discussed. A brief discussion on the current method of assessing the curing efficiency of chemical membranes is also presented.
CABRERA, JG, GOWRIPALAN, N & WAINWRIGHT, PJ 1989, 'AN ASSESSMENT OF CONCRETE CURING EFFICIENCY USING GAS-PERMEABILITY', MAGAZINE OF CONCRETE RESEARCH, vol. 41, no. 149, pp. 193-198.View/Download from: Publisher's site
The results of tensile and bending tests carried out on specimens of raffia bamboo are presented. Raffia bamboo are natural materials commonly used for the construction of buildings and household furniture in South Eastern Nigeria. The test results show that the material is capable of attaining an ultimate tensile strength of about 150 N/mm2 and a modulus of elasticity in tension of about 24 kN/mm2. These strength properties compare favourably with those of most natural timber species and also some oriented polymers used in fibre reinforced concrete. © 1989.
High strength polymer bars produced from thermoplastics were investigated with a view to using these as reinforcement, mainly for semi-structural concrete elements. This paper describes some of the properties of these bars and their possible applications. © 1987.
Gowripalan, N, Cao, J, Sirivivatnanon, V & South, W 2021, 'Comparison of the effect of ASR deterioration on the load carrying capacity of concrete structural elements in accelerated laboratory tests and in the field', 16th International Conference on Alkali Aggregate Reaction 2021, Lisbon, Portugal.
Gowripalan, N 2018, 'Autogenous Shrinkage of Concrete at Early Ages', ACMSM25, Australasian Conference on Mechanics of Structures and Materials, Springer, Brisbane, Australia.View/Download from: Publisher's site
Due to the high cementitious content and low water/binder ratios HPC and UHPC have a high autogenous shrinkage at early ages,. In this paper autogenous shrinkage of HPC and UHPC at very early ages are compared. The different components of shrinkage such as plastic, chemical, autogenous and drying are clearly differentiated.
Gowripalan, N & Cao, J 2019, 'Effect of Alkali Silica Reaction on bond strength and load capacity of reinforced concrete structures', FIB 2018 - Proceedings for the 2018 fib Congress: Better, Smarter, Stronger, pp. 3088-3099.
© 2019 by the fib. All rights reserved. Among the deterioration phenomena of reinforced concrete structures, alkali-silica reaction (ASR) is a potential source of long-term deterioration, particularly after 15 to 25 years of construction. Conventionally, in-situ load testing is employed, particularly for bridges, to assess the residual load capacity of the ASR affected super-structures. Such methods, however, are labour intensive, unsafe, time consuming and may cause unpredictable further damage to the structure. Assessing residual load carrying capacity of ASR affected reinforced concrete bridge super-structure is still unclear and not well understood. The long-term load carrying capacity of ASR affected reinforced concrete bridge super-structure consisting of beams and a deck slab is based on deteriorated beams and unaffected slab and this area needs further research. Often, when the neutral axis depth at ultimate limit state of bending falls below the soffit of deck level, there is a considerable reduction in the bending capacity can be expected, whereas, when the neutral axis depth falls within the in-situ slab thickness, bond deterioration may play a critical role in the moment carrying capacity reduction. While mid-span positions are critical for bending, as expected, shear capacity reductions are critical near support positions. In this paper, long-term bond deterioration between reinforcement and concrete, residual moment carrying capacity and residual shear capacity of beams due to ASR are discussed. The reduction in moment carrying capacity and shear capacity of beams and its effect on the over-all capacity of the bridge deck is also illustrated.
Gowripalan, N, Cao, J, Sirivivatnanon, V & South, W 2019, 'Assessment of ASR expansions using an ultra-accelerated test', 29th Biennial Conference of the Concrete Institute of Australia, Sydney Australia.
A constitutive model based on a novel coupled elastoplastic-damage framework is adopted for the modelling of concrete under cyclic loads. Coupled elastoplastic-damage models have been used to capture both the material degradation and the permanent deformations under inelastic deformations. In this study, a multisurface plasticity framework is implemented for the modelling of concrete under compressive and tensile cyclic loads. The elastoplastic-damage framework is based on the 'direct-coupling' method in which an a-priori relationship between the total strain and the damage strain is postulated. The model is easy to calibrate since it utilises the same yield and potential functions for plasticity and damage calculations. Concrete is modelled using a pair of yield surfaces in order to capture its compressive and tensile behaviour while utilising corresponding isotropic damage variables to capture the stiffness degradations in the compressive and tensile regimes. Material parameters are calibrated using uniaxially loaded concrete experiments. The results are compared with experimental and numerical data provided in the literature.
Vu, TH, Gowripalan, N, De Silva, P, Sirivivatnanon, V & Kidd, P 2018, 'Carbonation And Chloride Induced Steel Corrosion Related Aspects In Fly Ash/Slag Based Geopolymers - A Critical Review', Proceedings of the 2018 FIB Congress, International fib Congress, Fédération internationale du béton, Melbourne, Australia, pp. 3061-3076.
Carbonation and the presence of chloride ions are considered as two important factors affecting steel reinforcement corrosion in conventional ordinary Portland cement (OPC) concrete. Particularly, large OPC pre-cast pipes and culverts are expected to have a longer design life due to lower water/cement ratios and higher cement contents (hence higher strength and lower porosity). Although most of the time they are buried underground and corrosion conditions may not be present, the aggressive nature of fluids (highly acidic or salty) they carry internally and the aggressive ground water in which they are located have resulted in deterioration of these elements due to corrosion of steel. Nowadays, attempts are made to replace OPC concrete pipes or culverts with fly ash/slag based geopolymer pipes and culverts. In this paper, a comparison of the corrosion aspects of reinforced concrete elements, particularly, pre-cast pipes and culverts, manufactured of OPC or blended cements and fly ash/slag based geopolymers is made. Carbonation rate in OPC concrete is different to that of geopolymer concrete mainly due to different pore structure and reaction products. The chloride ion penetration will also be different mainly due to different binding capacity, chemical products and pore structure. The threshold concentration of chloride ions required to initiate corrosion of steel reinforcement is also different. These aspects are critically reviewed which includes diffusion rates and cover requirements for long-term performance.
Vu, TH, Gowripalan, N, Sirivivatnanon, V, De Silva, P & Kidd, P 2019, 'Assessing Corrosion Resistance of Powder form of Geopolymer Concrete', 29 Biennial Conference of the Concrete Institute of Australia, Sydney Australia.
Wang, JJ, Gowripalan, N, Li, J & Nguyen, VV 2016, 'Close-range photogrammetry for accurate deformation distribution measurement', Mechanics of Structures and Materials: Advancements and Challenges - Proceedings of the 24th Australasian Conference on the Mechanics of Structures and Materials, ACMSM24 2016, Australian Conference on the Mechanics of Structures and Materials, Taylor and Francis, Perth, Australia, pp. 793-799.
© 2017 Taylor & Francis Group, London. This paper introduces a methodology for improving the accuracy of Deformation Distribution Measurement (DDM) using close-range photogrammetry. After reviewing various algorithms for 2D Digital Image Correlation (DIC), Zero-Normalized Cross-Correlation (ZNCC) is selected for deformation measurement. The impact of several other factors on DIC measurement accuracy has been investigated, including the type of imaging sensors, the contrast and pattern of a specimen, and searching window size. Optimal option of these factors is proposed. The technique is utilized in the experiment of applying static loading on a replica of a concrete structural component used for Sydney Harbour Bridge. Test results presented in the paper include DIC measurements and validation data from conventional sensors.
Sanchayan, S, Gowripalan, N & Foster, SJ 2013, 'Mechanical properties of fibre reinforced reactive powder concrete after exposure to high temperatures', From Materials to Structures: Advancement Through Innovation - Proceedings of the 22nd Australasian Conference on the Mechanics of Structures and Materials, ACMSM 2012, pp. 1177-1181.
Reactive Powder Concrete (RPC) is a high-performance concrete that exhibits excellent mechanical properties and durability characteristics, owing to its homogeneity, dense microstructure and the presence of fibres. This research studies its behaviour with exposure to high temperature. The results include residual compressive strength and modulus of elasticity for two RPC mixes, one containing steel fibres and a second with PVA fibres. Temperature exposures up to 700°C were investigated. Testing of RPC cylinders containing steel fibres exposed to temperatures above 400°C show a violent explosive reaction under thermal loading with precautions needed in the laboratory to guard against the explosive effect.The results showan increase in residual compressive strength up to a temperature of 300°C; but beyond 300°C, the strength is reduced considerably. The elastic modulus also showed a steady loss at high temperatures and the research methodology and results are presented within. © 2013 Taylor & Francis Group.
Lim, CC, Gowripalan, N & Sirivivatnanon, V 2006, 'Predicting chloride content profile in concrete using a concrete mix design parameter', Concrete Repair, Rehabilitation and Retrofitting - Proceedings of the International Conference on Concrete Repair, Rehabilitation and Retrofitting, ICCRRR 2005, pp. 125-127.
Many service life prediction models for concrete require information from existing structure, for example, chloride concentration value at a known depth in concrete and the period of chloride exposure before a prediction can be made. Those models are useful when dealing with service life of existing concrete structures. In the case of designing a new concrete structure for service life, the prediction may be hindered because the required field information is not available at the time of design. Hence, a model which can give an estimate of the service life of a structure at the design stage is necessary. In the present study, a chloride concentration prediction model based on a concrete mix design parameter is proposed. The model is developed based on results of chloride immersion tests conducted in a controlled laboratory environment. The model is verified using data obtained from the present study and from the literature. The model can reasonably predict the chloride concentration profile in Ordinary Portland Cement (OPC) concretes having a water to cement ratio between 0.40 and 0.67. © 2006 Taylor & Francis Group, London.
Voo, JYY, Gilbert, I, Foster, S & Gowripalan, N 2004, 'Strength of D-regions in reactive powder concrete girders', Proceedings of the fib Symposium 2004 - Concrete Structures: The Challenge of Creativity, pp. 296-297.
This paper reports the results of tests on six reactive powder concrete deep panels. The panels were designed to simulate failure by bursting in the anchorage regions of prestressed concrete girders. Of particular interest were the development and growth of the splitting crack. The main conclusions are that the location of the bursting crack is dependant on the boundary arrangements; the quantity and type of fibres influences the growth and stability of the crack; and, with two percent by volume of fibres, the tearing load is at least twice the cracking load.
Voo, J, Foster, SJ, Gilbert, RI & Gowripalan, N 2003, 'Design of disturbed regions in reactive powder concrete bridge girders', High Performance Materials in Bridges, pp. 117-127.
In this paper the benefits of using reactive powder concrete (RPC) to carry bursting forces in prestressed bridge girders is investigated. Tests were undertaken on three RPC, 150 MPa, deep beams with the results reported. Also in this paper is a FE analysis of a 35 metre prestressed RPC bridge girder. The paper shows some of the significant potential advantages of using RPC in bridge engineering.
Voo, J, Foster, SJ, Gilbert, RI & Gowripalan, N 2001, 'Design of disturbed regions in reactive powder concrete bridge girders', HIGH PERFORMANCE MATERIALS IN BRIDGES, International Conference on High Performance Materials in Bridges, AMER SOC CIVIL ENGINEERS, Kona, HI, pp. 117-127.
Voo, JYL, Foster, S, Gilbert, RI & Gowripalan, N 2003, 'Behaviour of fibre reinforced RPC deep panels', ADVANCES IN STRUCTURES, VOLS 1 AND 2, International Conference on Advances in Structures, Steel, Concrete, Composite and Aluminium (ASSCCA 03), A A BALKEMA PUBLISHERS, SYDNEY, AUSTRALIA, pp. 1101-1106.
Gowripalan, N 2001, 'Fibre optic and piezoelectric sensors for structures with FRP: State of the art', FRP COMPOSITES IN CIVIL ENGINEERING, VOLS I AND II, PROCEEDINGS, International Conference on FRP Composites in Civil Engineering, ELSEVIER SCIENCE BV, HONG KONG, PEOPLES R CHINA, pp. 1635-1642.
Gowripalan, N, Zou, XW & Gilbert, RI 2000, 'Design considerations for ductility of prestressed beams with AFRP and CFRP tendons', ADVANCED COMPOSITE MATERIALS IN BRIDGES AND STRUCTURES, 3rd International Conference on Advanced Composite Materials in Bridges and Structures, CANADIAN SOCIETY CIVIL ENGINEERING, OTTAWA, CANADA, pp. 355-362.
Pillar, N & Gowripalan, N 2000, 'Post-cracking behaviour of fibre reinforced concrete at early ages', ADVANCED COMPOSITE MATERIALS IN BRIDGES AND STRUCTURES, 3rd International Conference on Advanced Composite Materials in Bridges and Structures, CANADIAN SOCIETY CIVIL ENGINEERING, OTTAWA, CANADA, pp. 77-84.
Zou, PXW, Gowripalan, N & Gilbert, RI 2000, 'An experimental study on the time-dependent behaviour of concrete beams prestressed by AFRP tendons', ADVANCED COMPOSITE MATERIALS IN BRIDGES AND STRUCTURES, 3rd International Conference on Advanced Composite Materials in Bridges and Structures, CANADIAN SOCIETY CIVIL ENGINEERING, OTTAWA, CANADA, pp. 169-176.
Bandyopadhyay, S, Kao, GJP, Gowripalan, N & Postle, R 1999, 'Atomic force microscopy study of carbon fibre reinforced cementitious composites', POLYMER COMPOSITES'99: AN INTERNATIONAL SYMPOSIUM ON POLYMER COMPOSITES SCIENCE AND TECHNOLOGY, SPE International Symposium on Polymer Composites Science and Technology, SOC PLASTICS ENGINEERS, LAC DELAGE, CANADA, pp. 53-+.
Gowripalan, N, Zou, XW & Gilbert, RI 1999, 'Deformability of prestressed beams with AFRP and CFRP tendons', MECHANICS OF STRUCTURES AND MATERIALS, 16th Australasian Conference on the Mechanics of Structure and Materials, A A BALKEMA PUBLISHERS, SYDNEY, AUSTRALIA, pp. 195-200.
Zou, XW, Gowripalan, N & Gilbert, RI 1997, 'Fibre reinforced plastics - Development and properties', MECHANICS OF STRUCTURES AND MATERIALS, 15th Australasian Conference on the Mechanics of Structures and Materials, A A BALKEMA PUBLISHERS, UNIV MELBOURNE, MELBOURNE, AUSTRALIA, pp. 75-81.
Zou, XW, Gowripalan, N & Gilbert, RI 1997, 'Flexural behaviour and ductility of HSC beams prestressed with AFRP tendons', MECHANICS OF STRUCTURES AND MATERIALS, 15th Australasian Conference on the Mechanics of Structures and Materials, A A BALKEMA PUBLISHERS, UNIV MELBOURNE, MELBOURNE, AUSTRALIA, pp. 135-140.
WAINWRIGHT, PJ, CABRERA, JG & GOWRIPALAN, N 1990, 'ASSESSMENT OF THE EFFICIENCY OF CHEMICAL MEMBRANES TO CURE CONCRETE', PROTECTION OF CONCRETE, INTERNATIONAL CONF ON PROTECTION OF CONCRETE, E & FN SPON, UNIV DUNDEE, DUNDEE, SCOTLAND, pp. 907-920.
Gowripalan, S, Shakil, J & Singh, G 1989, 'Life-Cycle Studies of a Concrete Structure using Simulation on a Microcomputer', Proceedings of the Fourth International Conference on Civil and Structural Engineering Computing, The Fourth International Conference on Civil and Structural Engineering Computing, Civil-Comp Press.View/Download from: Publisher's site