- Automation in Construction
- 3D Printing Concrete
- Concrete Technology
- Sustainable Materials
- Simulation Modelling
Teaching areas and interests
- Construction Materials
- Engineering Computation
- Concrete Design
- Engineering Mechanics
- Engineering Project Management
- Photogrammetry and Surveying
- Construction Technology
Self-compacting concrete (SCC) is a flowable type of concrete where minimum energy is required to form a structural component.
The high flow of SCC enables reduction in the number of workers, casting time, noise pollution and elimination of vibration.
Special mix design and the flowing nature of the concrete can change early age properties such as the lateral pressure on formwork
and shrinkage characteristics. This paper presents the background to SCC and discusses in detail the main aspects related to
formwork pressure and early age shrinkage of current SCC formulations.
Shakor, P, Nejadi, S & Paul, G 2020, 'Investigation into the effect of delays between printed layers on the mechanical strength of inkjet 3DP mortar', Manufacturing Letters, vol. 23, pp. 19-22.View/Download from: Publisher's site
© 2019 Currently, additive manufacturing have enabled to fabricate the three-dimensional models. 3D-Printing technique is a multipurpose process for producing structural members using a sequential layering approach. The "feature quality" of 3DP specimens can be improved by optimising the build constraints. In this paper, a mortar mix powder-base has been prepared that consists of cementitious materials. Experiments are conducted to investigate the effects of different delays in printing time on the mechanical properties of the scaffolds. It has been shown that the compressive stress and strength of printed specimens with a delay of 200 ms were greater than specimens with other delay values.
Shakor, P, Nejadi, S, Paul, G & Sanjayan, J 2020, 'Dimensional accuracy, flowability, wettability, and porosity in inkjet 3DP for gypsum and cement mortar materials', Automation in Construction, vol. 110.View/Download from: Publisher's site
© 2019 Inkjet (powder-based) 3D Printing is a popular and widely used technology, which can be applied to print a wide range of specimens using different powder materials. This paper discusses the use of inkjet 3DP technology for construction applications using custom-made powder instead of commercial gypsum powder (ZP 151). The paper aims to address the differences between ZP 151 and CP (a custom-made construction-specific cement mortar powder) with regard to powder flowability, wettability, powder bed porosity and apparent porosity in 3DP specimens. An inkjet 3D printer is employed and experimental results verify that ZP 151 has a lower angle of repose, a higher contact angle and noticeably less porosity in the powder bed compared with the CP powder. Additionally, specimens printed with ZP 151 have a lower apparent porosity compared with CP specimens. The wettability for each of the powders was tested using contact angle goniometer, while the Optronis Cam-Recorder was used at 1000 fps at 800 × 600 pixel resolution images for the powder flowability tests. The bulk density tester was utilised to find the apparent porosity in the printed specimens. The paper also discusses the details of the printing procedure and dimensional accuracy of printed specimens.
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.
Shakor, P, Nejadi, S & Paul, G 2019, 'A Study into the Effect of Different Nozzles Shapes and Fibre-Reinforcement in 3D Printed Mortar', Materials, vol. 12, no. 10.View/Download from: Publisher's site
Recently, 3D printing has become one of themost popular additivemanufacturing technologies.
This technology has been utilised to prototype trial and produced components for various applications,
such as fashion, food, automotive,medical, and construction. In recent years, automation also has become
increasingly prevalent in the construction field. Extrusion printing is the most successful method to print
cementitiousmaterials, but it still faces significant challenges, such as pumpability ofmaterials, buildability,
consistency in the materials, flowability, and workability. This paper investigates the properties of 3D
printed fibre-reinforced cementitious mortar prisms and members in conjunction with automation to
achieve the optimum mechanical strength of printed mortar and to obtain suitable flowability and
consistent workability for the mixed cementitious mortar during the printing process. This study also
considered the necessary trial tests, which are required to check the mechanical properties and behaviour
of the proportions of the cementitious mix. Mechanical strength was measured and shown to increase
when the samples were printed using fibre-reinforced mortar by means of a caulking gun, compared
with the samples that were printed using the same mix delivered by a progressive cavity pump to a
6 degree-of-freedom robot. The flexural strength of the four-printed layer fibre-reinforced mortar was
found to be 3.44 0.11MPa and 5.78 0.02MPa for the one-layer. Moreover, the mortar with different
types of nozzles by means of caulking is printed and compared. Several experimental tests for the fresh
state of the mortar were conducted and are discussed.
Shakor, P, Nejadi, S, Paul, G & Malekmohammadi, S 2019, 'Review of emerging additive manufacturing technologies in 3D printing of cementitious materials in the construction industry', Frontiers in Built Environment, vol. 4, pp. 1-17.View/Download from: Publisher's site
Shakor, P, Nejadi, S, Paul, G, Sanjayan, J & Aslani, F 2019, 'Heat Curing as a Means of Post-processing Influence on 3D Printed Mortar Specimens in Powder-based 3D Printing', Indian Concrete Journal, vol. 93, no. 09, pp. 65-74.
Inkjet (Powder-based) three-dimensional printing (3DP) shows significant promise in concrete construction applications. The accuracy, speed, and capacity to build complicated geometries are the most beneficial features of inkjet 3DP. Therefore, inkjet 3DP needs to be carefully studied and evaluated with construction goals in mind and employed in real-world applications, where it is most appropriate. This paper focuses on the important aspect of curing 3DP specimens. It discusses the enhanced mechanical properties of the mortar that are unlocked through a heat-curing process. Experiments were conducted on cubic mortar specimens that were printed and cured in an oven at a range of different temperatures (40, 60, 80, 90, 100°C). The results of the experimental tests showed that 80°C is the optimum heat-curing temperature to achieve the highest compressive strength and flexural strength of the printed mortar specimens. These tests were performed on two different dimensions of the cubic specimens, namely, 20x20x20 mm, 50x50x50 mm and on prism specimens with dimensions of 160x40x40 mm. The inkjet 3DP process and the post-processing curing are discussed. In addition, 3D scanning of the printed specimens was employed and the surface roughness profiles of the 3DP gypsum specimens and cement mortar are recorded 13.76 µm and 22.31µm, respectively.
Shakor, P, Nejadi, S, Paul, G, Sanjayan, J & Nazari, A 2019, 'Mechanical Properties of Cement-Based Materials and Effect of Elevated Temperature on Three-Dimensional (3-D) Printed Mortar Specimens in Inkjet 3-D Printing', ACI Materials Journal, vol. 116, no. 2, pp. 55-67.View/Download from: Publisher's site
Shakor, P, Sanjayan, J, Nazari, A & Nejadi, S 2017, 'Modified 3D printed powder to cement-based material and mechanical properties of cement scaffold used in 3D printing', Construction and Building Materials, vol. 138, pp. 398-409.View/Download from: Publisher's site
© 2017 Elsevier Ltd Additive manufacturing is a common technique used to produce 3D printed structures. These techniques have been used as precise application geometry in different fields such as architecture and medicine, and the food, mechanics and chemical industries. However, in most cases only a limited amount of powder has been used to fabricate scaffold (structure). In this study, a unique mix of cements (calcium aluminate cement passed through a 150 μm sieve and ordinary Portland cement) was developed for Z-Corporation's three-dimensional printing (3DP) process. This cement mix was blended and the resulting composite powders were printed with a water-based binder using a Z-Corporation 3D printer. Moreover, some samples were added lithium carbonate to reduce the setting time for the cement mixture. The aims of the study were to firstly, find the proper cementitious powder close to the targeted powder (Z-powder); and secondly, evaluate the mechanical properties of this material. Cubic specimens of two different batches with varying saturation levels were cast and cured in various scenarios to enhance the best mechanical properties. The samples were characterised by porosity analyses, compression tests, Olympus BX61 Microscope imaging, 3D profiling Veeco (Dektak) and the Scanning Electronic Microscope (SEM). The maximum compressive strength of the cubic specimens for cementitious 3DP was 8.26 MPa at the saturation level of 170% for both the shell and core. The minimum porosity obtained was 49.28% at the saturation level of 170% and 340% for the shell and the core, respectively.
Shakor, PN & Pimplikar, S 2011, 'Glass fibre reinforced concrete use in construction'.
Shakor, P, Nejadi, S & Gowripalan, N 2020, 'Effect of Heat Curing and E6-Glass Fibre Reinforcement Addition on Powder-Based 3DP Cement Mortar' in P. Bos, F, S. Lucas, S, J.M. Wolfs, R & A.M. Salet, T (eds), Second RILEM International Conference on Concrete and Digital Fabrication, Springer, Cham, EindhovenThe Netherlands, pp. 508-515.View/Download from: Publisher's site
Powder-based 3D printing is one of the most promising techniques in additive manufacturing. The speed, resolution of the printed part and complicated geometries are important features in this technique and these features are usually not experienced in traditional construction techniques. This study aims to discuss the concept of using a custom-made powder (cement mortar) instead of a commercial (gypsum) powder in 3DP. Therefore, broad investigations are required to study and understand the details of the cement mortar 3D printed scaffold. This paper discovers the effect of heat-curing and addition of E6-glass fibres as reinforcement for the printed specimens. The results show that the mechanical properties of the cement mortar are improved through a heat-curing procedure. Addition of fibre reinforcement enhances powder flowability consistency and surface roughness throughout. Experiments are conducted on printed 50 mm cubic specimens, cured in an oven at different temperatures. The optimum heat-curing temperature is found to be 80 °C to achieve the highest compressive strength in cement mortar specimens. Detailed 3D laser scanning of the printed cement mortar specimens is conducted. The 3D laser scanning results found rougher surface in cement mortar when it is not reinforced with glass fibre.
Shakor, P, Nejadi, S & Paul, G 2019, 'An Investigation into the Effects of Deposition Orientation of Material on the Mechanical Behaviours of the Cementitious Powder and Gypsum Powder in Inkjet 3D Printing', Proceedings of the 36th International Symposium on Automation and Robotics in Construction (ISARC), 36th International Symposium on Automation and Robotics in Construction, International Association for Automation and Robotics in Construction (IAARC), Banff, AB, Canada.View/Download from: Publisher's site
Shakor, P, Nejadi, S & Paul, G 2019, 'Effect of Elevated Temperatures as a Means of Curing in Inkjet 3D Printed Mortar Specimens', Biennial National Conference of the Concrete Institute of Australia, Concrete Institute of Australia, Sydney, Australia.
Inkjet (Powder-based) three-dimensional printing (3DP) shows significant promise in concrete construction applications. The accuracy, speed, and capability to build complicated geometries are the most beneficial features of inkjet 3DP. Therefore, inkjet 3DP needs to be carefully studied and evaluated with construction goals in mind and employed in real-world applications, where it is most appropriate. This paper focuses on the important aspect of curing 3DP specimens. It discusses the enhanced mechanical properties of the mortar that are unlocked through a heat-curing process. Experiments have been conducted on cubic mortar samples that have been printed and cured in an oven at a range of different temperatures (e.g. 40, 60, 80, 90, 100°C). The results of the experimental tests have shown that 80°C is the optimum heat-curing temperature to achieve the highest compressive strength and flexural strength of the printed samples. These tests have been performed on two different dimensions of the cubic specimens 20x20x20mm, 50x50x50mm and on prism specimens with the dimensions of 160x40x40mm. The inkjet 3DP process and the post-processing curing are discussed. Additionally, 3D scanning of the printed specimens is employed and the surface roughness profiles of the 3DP specimens are presented.
Shakor, P, Nejadi, S & Paul, G 2018, 'An investigation into the behaviour of cementitious mortar in the construction of 3D printed members by the means of extrusion printing', 1st International Conference on 3D Construction Printing, Melbourne, Australia.
Shakor, P, Nejadi, S, Paul, G & Sanjayan, J 2018, 'A Novel Methodology of Powder-based Cementitious Materials in 3D Inkjet Printing for Construction Applications', Whittles Publishing, Sixth International Conference on Durability of Concrete Structures, Whittles Publishing, University of Leeds, Leeds, West Yorkshire, LS2 9JT, United Kingdom, pp. 685-659.
Shakor, P, Renneberg, J, Nejadi, S & Paul, G 2017, 'Optimisation of Different Concrete Mix Designs for 3D Printing by Utilising 6DOF Industrial Robot', 34th International Symposium on Automation and Robotics in Construction, Taipei, Taiwan.
Additive Manufacturing (AM) technologies are becoming increasingly viable for commercial and research implementation into various applications. AM refers to the process of forming structures layer upon layer and finds application in prototyping and manufacturing for building construction. It has recently begun to be considered as a viable and attractive alternative in certain circumstances in the construction industry. This paper focuses on the utilisation of different concrete mixtures paired with extrusion techniques facilitated by a six Degree of Freedom (DOF) industrial robot. Using methods of Damp Least Squares (DLS) in conjunction with Resolved Motion Rate Control (RMRC), it is possible to plan stable transitions between several waypoints representing the various print cross-sections. Calculated paths are projected via 'spline' interpolation into the manipulator controlled by custom software. This article demonstrates the properties of different concrete mixture designs, showing their performance when used as a filament in 3D Printing and representing a comparison of the results that were found. In this study, the prepared materials consist of ordinary Portland cement, fine sand between (425~150) micron, coarse aggregate ranges (3) mm and chemical admixtures which have been used to accelerate setting times and reduce water content. Numerous tests were performed to check the buildability, flowability, extrudability and moldability of the concrete mixtures. The horizontal test was used to determine the flowability and consistency, while the vertical and squeeze-flow tests were used to determine the buildability of the layers. The extrudability and moldability of the concrete mixtures were controlled by the robot and associated extruder speeds.
Shakor, PN & Kekan, S 2013, 'Fuel consumption & air pollution analysis by vehicles coming into MIT CAMPUS & compare with DTI', AES-ATEMA International Conference Series - Advances and Trends in Engineering Materials and their Applications, pp. 113-123.
Air pollution is the introduction into the atmosphere of chemicals, particulates, or biological materials that cause discomfort, disease, or death to humans, damage other living organisms such as food crops, or damage the natural environment or built environment. The atmosphere is a complex dynamic natural gaseous system that is essential to support life on planet Earth. Mostly pollution known put something in the air and hurt it. So here will show some data and confirm how the impact effect of vehicle in environment, and directly polluted by huge ratio in the air approximately 1/3 known as transportation pollution. The second sector is consume of fuel by huge rate which economically not accepted beside that contribute in crowd traffic and more accident on highway and roads. The report aims to identify the necessity of understanding the impact of vehicular pollution on the environment. In order to bring the fuel consumption and emission levels to a minimum, various mitigation measures are to be implemented, which are also pointed out in the report. © 2013, Advanced Engineering Solutions (AES.COM).
Shakor, PN, Pimplikar, SS & Ghare, UM 2011, 'Techno-commercial aspects of use of glass fibre-reinforced concrete in construction industry', AES-ATEMA International Conference Series - Advances and Trends in Engineering Materials and their Applications, pp. 457-462.
Glass-fibre reinforced concrete (GRC) is a material made of a cementatious matrix composed of cement, sand, water and admixtures, in which short length glass fibres are dispersed. It has been widely used in the construction industry for non-structural elements, like façade panels, piping and channels. GRC offers many advantages, such as being lightweight, fire resistant, good appearance and strength. Various applications of GFRC shown in the study, the experimental test results, techno-economic comparison with other types, as well as the financial calculations presented, indicate the tremendous potential of GFRC as an alternative construction material. Glass fibre is used in a variety or large number of fields. Presently it is used widely in the field of engineering particularly in the field of civil engineering which includes building concrete wall, sewerage pipe, stairs, interior and exterior decoration of buildings, etc. It is used to a great degree for covering interior and exterior walls of buildings. The present study attempts at collecting data related to the use of GRC in various applications such as building, roads and bridges, and to explore the techno-commercial aspects. © 2011, Advanced Engineering Solutions.