Development of 3D-printable mortars from waste stream products
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Kemian tekniikan korkeakoulu | Master's thesis
Master's Programme in Chemical, Biochemical and Materials Engineering
AbstractThe use of cement and its environmental effects are the major concerns for construction industries. To minimize the use of cement, different recycled materials are giving a novel thought in making the construction sector sustainable for the environment. A possible alternative to conventional concrete printing is 3D concrete printing. As a result, construction productivity can be increased and environmental impacts can be reduced. The aim of this work is to adopt new construction methods and materials which should result in better and more advanced building methods. This research work focuses on using recycled materials for testing and constructing small objects using 3D printing technology. The recycled materials considered in this research work are Ground granulated blast furnace slag (GGBFS) and Silica fume (SF). The work is based on the research and development of creating a new mortar recipe that can be 3D printable. The recipes are formulated based on the incorporation of different admixtures, including a new agent which is a viscosity modifying agent (VMA) which was chosen from different chemical formulations. These samples were tested with various fresh and hard-state test methods. One important property associated with VMA is Thixotropy, which was considered and evaluated throughout the mixing design. VMAs are long-chain polymers and these are entangled when at rest and at the high shear rate they align with the flow making the mortar mix workable and get adsorbed on the surface of the water molecule causing expansion and restricting the movement and increasing water holding capacity of the mix. This makes the VMA an important candidate in the mortar mix. The correct dosage of VMA is calculated under the influence of different admixtures like superplasticizers, and accelerators with the mortar and then printed. Different proposed dosages of VMA in the fixed mortar recipe were printed into test samples and the observed results are considered till a suitable dosage was found.
Thesis advisorMohite, Ashish
3D printing, additive manufacturing, cementitious materials, GGBFS