Effect of curing methods during a long time gap between two printing sessions on the interlayer bonding of 3D printed cementitious materials

A good bond between the layers of 3D printed cementitious materials is a prerequisite for having high structural rigidity for the printed elements. However, the influence of printing process on an interlayer bond is still not well understood. This study investigates the influence of curing methods (i.e., air curing, plastic film covering, wet...

Hydration heat, strength and microstructure characteristics of UHPC containing blast furnace slag

Ultra-high performance concrete (UHPC) is an innovative cement-based composite with high mechanical performance under tensile and compressive loads, extremely low permeability, and excellent durability. Because of these features, UHPC has the potential to contribute to the development of new architectural perspectives and structural systems...

Elephant skin formation on UHPC surface: Effects of climatic condition and blast furnace slag content

Ultra-high performance concrete (UHPC), which typically contains extremely high superplasticizer amount, tends to render a special type of dense surface layer, especially under drying conditions. Even if the inner side of fresh UHPC is still in a flowable nature, the top surface of the concrete which is exposed to ambient conditions renders a...

Microscopy techniques for determining water–cement (w/c) ratio in hardened concrete: A round-robin assessment

Water to cement (w/c) ratio is usually the most important parameter specified in concrete design and is sometimes the subject of dispute when a shortfall in concrete strength or durability is an issue. However, determination of w/c ratio in hardened concrete by testing is very difficult once the concrete has set. This paper presents the...

Effect of viscosity modifier admixture on Portland cement paste hydration and microstructure

Significant attention has been given to the development of new materials and techniques to be employed in the construction market. One of the techniques which has drawn noticeable attention is the additive manufacturing process (a.k.a. 3-dimensional printing (3D printing)). One of the approaches of this construction technique is the extrusion of...