Viscosity is a key parameter in 3D concrete printing, influencing printability, structural stability, and interlayer adhesion. Hydramotion sensors provide real-time viscosity monitoring to maintain process consistency and product quality.
XL5 Sensor 2" Tri-clamp |
XL5 Sensor 1.5" Tri-clamp |
3DCP Process Overview
3D concrete printing (3DCP), also called concrete additive manufacturing, is an emerging construction technique that is gaining traction as a method to automate construction without formwork or heavy manual labor.
By extruding cement-based mixtures directly from digital models, structures can be built layer by layer, similar in principle to polymer 3D printing but with cementitious materials.
This provides significant cost savings over conventional building methods and allows for the direct fabrication of complex designs with less material. Viscosity plays a central role in ensuring consistent flow, proper layer bonding, and reliable printability of the cement.
The 3DCP process is structured around four main stages:
Mixing
Cement, sand, and additives are combined to create the core mixture. Formulations balance flowability during pumping with strength after deposition, often using retarders and accelerators to manage setting times. The formulation is mixed continuously with water as part of the hydration process.
Secondary mixing may occur before extrusion depending on further additive requirements to optimise material stiffness and strength.
Pumping
Progressive cavity pumps deliver the fresh mix to the printing nozzle. Flow consistency is critical to avoid print interruptions and maintain structural build rate.
Extruding
A nozzle is mounted on a robotic arm or gantry and deposits the material through controlled extrusion.
Building
The extruded material is deposited in programmed layers, allowing the structure to be built progressively as each layer supports the next.
Process Challenges and Viscosity Control
Concrete’s dual rheological behaviour - solid-like below certain shear stress and fluid-like when sheared - creates processing challenges that directly affect the performance and output quality.
The material must pump easily but stiffen quickly to hold shape after extrusion. Whilst also supporting its own weight and bonding effectively with adjacent layers. Controlling the mixing, pumping and extrusion process is critical to preserving buildability and structural integrity.
In 3DCP, viscosity links directly to printability. Too low, and layers slump or collapse; too high, and pumping stalls or the nozzle clogs. Real-time measurement and control of viscosity gives operators the feedback needed to maintain optimal flow and quality, and take corrective action within a desired band.
While yield stress is also central to the broader rheology profile, viscosity is the more practical control parameter for real-world 3DCP, as it directly governs flow resistance and consistency, and in practice provides a reliable proxy for shape retention.
Inline Viscosity Monitoring Solution
Hydramotion viscosity sensors are well suited to concrete measurement and the 3DCP process due to their robust and high performance nature. The sensors can be installed in either the mixing, pumping or extrusion process phases.
For optimal installation, the transducer is mounted either in the hopper or adjacent pipeline directly in the heart of the flow. There are generally no limitations on pipe size or maximum flow rates, and engineered solutions are available to optimise installation points and exposure to flow.
Due to concretes composition and abrasive properties, all Hydramotion sensors have the option of fabrication from high strength alloys such as Super Duplex 2507, and are available with virtually any process fitting.
Typical dimensions can be seen below for an indicative XL5 sensor. Hydramotion also offers a bespoke design service - Special Ops - where a sensor of virtually any size or geometry can be designed to fulfil the requirements of the application.
Download indicative XL5 GA drawing file >
Welds are smooth and crevice-free with open construction for easy cleaning and to eliminate contaminant traps.
All viscometers are supplied with process fittings to match the connections that already exist on your equipment. This includes any size or type of sanitary fitting, including quick-release tri-clamp mountings, RJT, IDF, DIN, SMS, Varivent® and others.
Ready to learn more?
Contact Hydramotion to discuss your 3DCP application requirements. Or visit the following links to learn more about Hydramotion viscosity sensors.