19 research outputs found
Effect of limestone powder substitution on fresh and hardened properties of 3D printable mortar
Great progress has been made in 3D concrete printing (3DCP) in the
past few years. The unique advantages of 3DCP over conventional concrete
construction may include saving costs and labor, eliminating formwork,
reducing the construction time, as well as increasing flexibility in architectural
design. To satisfy the printing requirements, a high amount of binders is used for
3DCP. Among all the binders, ordinary Portland cement (OPC) is the most
commonly used binder for 3DCP. However, producing OPC consumes high
amounts of energy and exhausts high amounts of greenhouse gases. Therefore,
with a high amount of OPC, 3DCP cannot be treated as a sustainable and
environmental friendly construction method. Partially replacing OPC by supplementary
cementitious materials (SCMs) might be a proper solution to make
the 3D printable concrete sustainable. Limestone powder (LP) is one of the
SCMs with the advantage of wide availability and low cost. This study analyzed
the impact of substituting OPC by LP on the fresh and hardened properties of
3D printable mortar. Six mixtures with three LP substitution rates (0%, 25%,
and 50% by volume of OPC) were designed. In the fresh stage, a squeeze flow
test was used for evaluating the shape stability. In the hardened stage, drying
shrinkage and mechanical properties were investigated. The results showed that
a high amount of LP substitution had negative effects on both fresh properties
and hardened properties. However, for a lower replacement percentage (i.e. a
25% replacement rate), the strength loss is still within reasonable limits