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3D Printing Technology Utilizing Available Construction Materials in the UAE
Ahmed, Sara Khaled
Ahmed, Sara Khaled
Description
A Master of Science thesis in Civil Engineering by Sara Khaled Ahmed entitled, “3D Printing Technology Utilizing Available Construction Materials in the UAE”, submitted in November 2019. Thesis advisor is Dr. Sherif Yehia. Soft copy is available (Thesis, Approval Signatures, Completion Certificate, and AUS Archives Consent Form).
Abstract
Over the past decade, rapid developments in 3D printing technology was observed within the construction industry. 3D printing is an innovative construction technique which may be referred to as automated construction, digital or additive manufacturing. This technology has the ability to build complex structures with no formworks, reduces construction costs and material usage, which will allow for the adoption of a sustainable built environment. However, there are still many challenges that limit the capabilities of 3D printing. To develop concrete which is pumpable, extrudable, and buildable, the workability of the fresh printing concrete is the key factor that has to be evaluated and monitored over time. This study aims to develop a 3D printing concrete using locally available materials and to asses it in terms of its fresh properties. The experimental program involved two phases. In phase 1 evaluation two groups of mixes were developed mainly to examine the effect of supplementary cementitious materials (Ground-granulated blast-furnace slag and Silica fume) on the extrudability and compressive strength. The optimal mix of phase one was found to be the mix containing both crushed and dune sand, and GGBS and SF combined. In phase 2 evaluation, the optimal mix was selected from phase 1, and was developed with three different aggregate to binder (a/b) ratios of 1.2, 1.5, and 1.8. The evaluation criteria included the extrudability, setting-time, open-time, workability, and buildability of the mixes. The workability was assessed in terms of the penetration, slump, and flow. The results of phase two suggest that the extrudability was best monitored with the flow test as compared to the slump and penetration tests. The optimal slump and flow percentage ranges that maintain acceptable extrudability were 85-0 mm and 90-45%, whereas, the buildability was performed at a slump and flow of 45-50 mm and 66%. The increase in a/b ratio led to mixes with higher buildability. Finally, the compressive strength of printed specimens of phase 2 mixes was also evaluated and the results demonstrated that the strength of the specimens decreased with the increase in a/b ratio.