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

© 2019 International Association for Automation and Robotics in Construction I.A.A.R.C. All rights reserved. Three-Dimensional Printing (3DP) is widely used and continues to be rapidly developed and adopted, in several industries, including construction industry. Inkjet 3DP is the approach which offers the most promising and immediate opportunities for integrating the benefits of additive manufacturing technic into the construction field. The ability to readily modify the orientation angle that the printed material is deposited is one of the most advantageous features in a 3DP scaffold compared with conventional methods. The orientation angle has a significant effect on the mechanical behaviours of the printed specimens. Therefore, this paper focuses on printing in different orientations somehow to compare various mechanical properties and to characterise a selection of common construction materials including gypsum (ZP 151) and cement mortar (CP). The optimum strength for the gypsum specimens in compression and flexural strength was observed in the (0° and 90°) and (0°) in the X-Z plane, respectively. According to the experimental results, the compression and flexural strength for ZP 151 are recorded at (11.59±1.18 and 11.78±1.19) MPa and 15.57±0.71 MPa, respectively. Conversely, the highest strength in compression and flexural strength are observed in the (90°) and (0°) degrees in the X-Z plane for the cement mortar, respectively. Moreover, it has been discovered that the compression and flexural strengths for CP are recorded as 19.44±0.11 MPa and 4.06±0.08 MPa, respectively. In addition, the dimensional effect for various w/c ratio has been monitored and examined

Optimisation of different concrete mix designs for 3D Printing by utilising 6DOF industrial robot

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 (425-450) 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

Experimental and numerical analysis of 3D printed cement mortar specimens using inkjet 3DP

Investigations involving the experimental and numerical analysis of inkjet (powder-based) 3DP are relatively limited for cement mortar materials. This study, by using cement mortar specimens, aimed to determine the optimum strength of 3D printed structural members in all three planes by identifying the compressive strength of cubes, the modulus of elasticity and Poisson’s ratio. In addition, this study aimed to analyse and verify the numerical model for 3D printed cementitious mortar (CP) prisms and beams using an inkjet 3D printer by considering the mechanical behaviour of the printed prisms under compression. Robust and optimal mechanical properties of the 3D printed cementitious mortar obtained from laboratory testing were utilised in the simulation of structural components using ABAQUS software. As inputs for simulation, the strength properties of the printed objects in all three cartesian planes were obtained from test results. The obtained results showed that the printed cementitious materials have orthotropic properties and that the results of experiments were consistent with the analytical solutions and hypothesised model for the different geometric shapes. This finding is extremely valuable in determining the optimum features of 3D printed structures

An environmental sustainability roadmap for partially substituting agricultural waste for sand in cement blocks

Agricultural waste can be used in cement block production for a number of reasons, including its environmental, economic, and labor benefits. This study examines the mechanical, durability, and cost-effectiveness characteristics of cement blocks. A cement block made from agriculture waste promotes sustainable construction practices, since waste agriculture is often dumped in landfills and regarded as a waste material. Carbon dioxide (CO2) emissions produced by the construction sector, either from the firing of clay bricks or from the production of cement, contribute significantly to global warming. In many developing countries, air pollution from agricultural activities is primarily accounted for the emissions from agricultural machinery and openly burning agro-waste. Farming is one of the leading causes of water and soil pollution. Hence, adopting agricultural waste into cement production would significantly reduce the environmental impact of concrete structures. The goal of this research is to determine whether agricultural waste products, such as vermiculite, pistachio shells, sugarcane bagasse, and coconut husks, can be used to substitute sand in concrete blocks. The water absorption capacity of waste materials, density, flexural strength, fire resistance, and compressive strength of waste materials as admixtures in concrete were evaluated using experimental tests. In most cases, the concrete blocks made from agricultural waste were strong enough to satisfy ASTM standards. The specimens containing coconut husks and pistachio shells, among others, were found to be fairly strong and durable, even when isolating them from water

Predicting Compressive Strength of 3D Printed Mortar in Structural Members Using Machine Learning

Machine learning is the discipline of learning commands in the computer machine to predict and expect the results of real application and is currently the most promising simulation in artificial intelligence. This paper aims at using different algorithms to calculate and predict the compressive strength of extrusion 3DP concrete (cement mortar). The investigation is carried out using multi-objective grasshopper optimization algorithm (MOGOA) and artificial neural network (ANN). Given that the accuracy of a machine learning method depends on the number of data records, and for concrete 3D printing, this number is limited to few years of study, this work develops a new method by combining both methodologies into an ANNMOGOA approach to predict the compressive strength of 3D-printed concrete. Some promising results in the iteration process are achieved.</jats:p

PRESSURE EXERTED ON FORMWORK AND EARLY AGE SHRINKAGE OF SELF-COMPACTING CONCRETE

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

Pressure exerted on formwork by self-compacting concrete at early ages: A review

Self-Compacting Concrete (SCC) is a flowable concrete that exerts high pressure on formwork. SCC is the most commonly used concrete worldwide for construction applications due to its cost-effectiveness. The high flow of SCC reduces both the number of workers and the casting time required. It also eliminates vibration and removes noise pollution. This study is a review of previous investigations into the pressure exerted by fresh-state SCC on formwork. The paper discussed various factors that affect lateral pressure on formwork. These factors are included theoretical predictions, the effect of temperature, casting rate, rheology, types of pressure sensors, geometry and workability. Considering these various factors, the paper discussed major factors related to lateral pressure of SCC at early ages. However, internal temperature measurement of concrete effects at fresh state appears to be an important factor

Additive Manufacturing for Construction

Additive Manufacturing for Construction reveals additive manufacturing technologies for building and construction applications. It introduces digital and multiuse technologies for civil applications and informs the reader of their design properties and uses. The book explores on-site and off-site construction techniques, and features design strategies in additive manufacturing which will eliminate production difficulties and minimise assembly costs, from both the academic and the industrial perspectives. The unique capabilities of additive manufacturing technologies for large-scale applications combined with 'design for manufacturing' strategies are shown, allowing the reader to understand efficient structural shapes and forms which can provide appropriate level of structural performance with reduced use of materials and resources.Additive Manufacturing for Construction reveals additive manufacturing technologies for building and construction applications. It introduces digital and multiuse technologies for civil applications and informs the reader of their design properties and uses. The book explores on-site and off-site construction techniques, and features design strategies in additive manufacturing which will eliminate production difficulties and minimise assembly costs, from both the academic and the industrial perspectives. The unique capabilities of additive manufacturing technologies for large-scale applications combined with 'design for manufacturing' strategies are shown, allowing the reader to understand efficient structural shapes and forms which can provide appropriate level of structural performance with reduced use of materials and resources. This book gathers knowledge of multidisciplinary investigations into one book to answer challenges and difficulties faced by the construction industry and includes: extrusion-based concrete additive manufacturing particle bed additive manufacturing shotcrete additive manufacturing wire-and-arc metal additive manufacturing simulation modelling of concrete 3D printing Additive Manufacturing for Construction is of interest to those in academia and industry including architects, civil engineers, material engineers, manufacturing and industrial engineers, mechatronic engineers and construction experts with an interest/professional requirement to know about large-scale additive manufacturing technologies