The Effect Of Viscosity Modifier Agent On The Early Age Strength Of The Limestone And Calcined Clay-Based Sustainable And 3D Printable Cementitious Material

Recently, our group attempted to develop the ternary blended (Portland cement, calcined clay and limestone) cementitious material for 3D concrete printing (3DCP). Due to the elimination of formwork during the layer-by-layer casting process, the printed material should have favorable elastic properties and green strength at the fresh state. A...

Deliberate Deformation of Concrete in the Fresh State: Crack Risk and Efficient Production of Curved Precast Elements

The production of double-curved precast concrete elements for cladding or shell structures requires expensive CNC (computer numerical control)-milled formwork. As an alternative method, the innovative flexible mould for economically efficient and sustainable production of such elements is discussed in this paper. This method comprises the use of...

Feasibility of Using Low CO2 Concrete Alternatives in Extrusion-Based 3D Concrete Printing

In conventional concrete, replacing high-volume (more than 45%) of ordinary Portland cement (OPC) by supplementary cementitious materials (SCMs) is not a novel CO2 reduction method, whereas rarely in 3D printable concrete. This study attempts to explore the feasibility of using SCMs in 3D printable concrete. Initially, the existing binder mixes,...

Piezoresistive properties of cementitious composites reinforced by PVA fibres

The use of fibres to enhance the ductility of cementitious composites has been extensively studied for the past few years. The addition of polymeric or metalic fibres with random orientation to the composite or even natural long and aligned fibres demonstrated a very successful reinforcement capable to reach a high mechanical performance....

Assessment of concrete characteristics during the deliberate deformation of a flexible mould after casting

Expensive CNC (computer numerical controlled)-milled formwork is required for the production of double-curved precast concrete elements for cladding or shell structures. The innovative flexible mould method for economically efficient and sustainable production of such elements, developed at Delft University of Technology, comprises the use of a...

Experimental and numerical study on cement paste degradation under external sulfate attack

External sulfate attack is one of the situations that may cause gradual but severe damage in cementitious materials, which may lead to cracking, increased permeability and strength loss. In this paper, thin-walled hollow cement paste cylinders with a wall thickness of 2.5mm were made considering the slow penetration process of sulfate ions under...

Using nano-indentation and microscopy to obtain mechanical properties

Simulation of mechanical behaviour of heterogeneous materials is only possible if the local properties of the components are known. In recent years nano-indentation is being applied on different levels to obtain local mechanical properties. The aim of this paper is to explore various ways to obtain these properties by combining nano-indentation...

A tool for concrete performance assessment for ASR affected structures: An outlook

This paper outlines a project (namely PAT-ASR) which entails the development of a multi scale material performance assessment model on simulation of alkali silica reaction deployment and its effects on concrete durability. Performance models require a multi scale approach from micro (namely reaction chemistry) to macro level studies (namely...

Modeling of expansion and cracking due to ASR with a 3D lattice model

It is generally possible to consider modeling of ASR damage in concrete in two main groups: modeling of gel formation and its expansion; modeling of ASR related damage. In this paper, authors take an attempt to combine both: simulating the correct crack formation and the connected concrete expansion. It is aimed to simulate ASR damage in a...