Sustainable construction innovation: 3D printing is revolutionizing the concrete industry!

Sustainable construction innovation: 3D printing is revolutionizing the concrete industry!

The construction industry faces the urgent challenge of significantly reducing resource consumption and CO2 emissions. A promising solution in this context is research at the Institute for Particle Technology at the Technical University of Braunschweig and at the Technical University of Munich. The focus here is on the development of environmentally friendly materials, with a particular focus on the 3D printing technology “Selective Paste Intrusion” (SPI). This innovative method aims to recover recycled particles from recycled concrete from demolished buildings, which could lead to more sustainable construction in the long term.

SPI technology revolutionizes concrete construction by distributing aggregates in thin layers and bonding them with cement paste. A deep understanding of particle technology is crucial for improving energy efficiency and sustainability in construction. Fresh concrete consists of water, cement and aggregates such as sand and gravel. However, recycling concrete is a complex task because the rock grains are connected by the cement matrix.

Mechanical crushing and use of recycled concrete

Two methods of mechanical crushing are used to prepare concrete: first, impacting a particle on a hard surface and second, compressive and shear stress between two surfaces, with the latter being preferred. Selective comminution enables the material to be broken down in a controlled manner, leaving the rock grains intact. After crushing, the particles are classified and cleaned so that coarse aggregates can be reused for the production of new building materials. Fine cement particles, on the other hand, can be used as an additive in cement paste. However, strict regulations on the reuse of recycled concrete often stand in the way of the effective use of valuable materials.

This is where SPI technology comes into play by creating a sustainable cycle and making it possible to give discarded materials a second chance. This approach could bring significant long-term changes to the construction industry.

SPI and its application in practice

The companies Scawo3D and Skeno presented the SPI technology at BAU 2025 in Munich. Their innovative 3D concrete printing method uses a novel inkjet print head that deposits cement paste within loose aggregates to effectively realize complex structures. Integration of computer-aided design tools such as Spherene for Rhino/Grasshopper enables the creation of delicate geometries and optimized structural performance. During the trade fair, the exhibition stand served not only as a demonstration, but also as a research example for SPI applications in load-bearing structures.

The stand, with an area of ​​25 m² and 3 m high back walls, featured Spherene structures divided into six modules weighing between 150 and 320 kg. A central wall bearing Scawo3D's logo was segmented for efficient transportation. Additionally, a 3D printed staircase was presented in collaboration with Skeno and Timo Harboe, demonstrating SPI's ability to produce complex, load-bearing structures. The entire process involved a large particle bed (4 x 2.5 x 1.5 meters) and followed a layer-by-layer technique for precision.

The rapid manufacturing method of SPI technology reduces production time and minimizes material waste compared to traditional concrete construction methods. For the BAU 2025 stand, the back panels were printed in a single session of just six hours, using lightweight expanded clay material. The remaining components were produced within four hours using quartz-containing sand aggregates. Such advanced manufacturing methods powerfully demonstrate the potential of SPI and computer-aided design tools to redefine architectural possibilities and promote sustainable construction practices. The collaboration between Scawo3D, Skeno and Spherene marks a significant advancement in the field of digital fabrication in concrete architecture.