Sonocrete has developed a premixing device that uses power ultrasound to make concrete harden faster. Thus, precast concrete parts can be stripped earlier or can be produced with low-carbon cements or less heat, making concrete climate-friendly. Now the technology has successfully proven its industrial suitability in the MATTIG& LINDNER precast plant close to Berlin, Germany.

Sonocrete makes concrete more sustainable

Concrete producers face many challenges: The demand for concrete elements will continue to increase, but these elements will increasingly have to meet ecological requirements and be produced with less CO₂ emissions.

The founders of Sonocrete GmbH, Dr. Christiane Rößler and Ricardo Remus, have been researching the influence of high-performance ultrasound on concrete hardening for years. Faster hardening enables finished parts to be stripped more quickly. This way production can be increased, climate-friendly cements can be used, or heat treatment can be reduced. The CO₂ footprint of the concrete is significantly reduced.

In the Sonocrete pre-mixing device, cement and water are premixed for a short time and treated with high power ultrasound. The ultrasound leads to cavitation in the suspension. The resulting local extreme pressures cause the concrete to harden faster.

Until now, the Sonocrete pre-mixer was only available in lab size. Some days ago, the Sonocrete team used the first spring days for a factory test. The Sonocrete technology was used for the first time in a real concrete plant of MATTIG & LINDNER GmbH as part ofa BMBF-funded research project.

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Sonocrete in the factory

The test started in Forst after the regular concrete for this day had been cast. The Sonocrete pre-mixer was unloaded and put up right next to the concrete mixer in the plant.

Three different concrete mixtures were tested, all based on the same formulation with identical starting materials. First, the normal concrete was mixed as a reference, while the other two mixtures were treated in the Sonocrete pre-mixer. Within a few minutes, the cement-water suspension in the mixer was ready to be put into the large concrete mixer. There, gravel and sand were added and the concrete was cast into ceiling moulds.

The finished fresh concretes were measured in terms of slump flow, temperature and air void content were measured. Standardized cubes were cast for later compressive strength testing.

Results from the factory test

The test results show the success of the first Sonocrete factory test. After 24 hours, the strength of the sonicated concrete is three times higher than the strength of the reference concrete. This results in an acceleration of approx. 8 hours –thanks to the short use of ultrasound, the concrete could be stripped 8 hours earlier. Alternatively, the use of heat treatment could be completely abandoned.

Sonocrete was able to show that an ultrasound activation of the cement suspension leads to significantly increased early concrete strength in a real plant setting.

The Sonocrete team gathered a lot of valuable information from the test. Smaller problems that occurred – e.g., the USB cable that got crushed during unloading – could be quickly resolved.

Michael Lindner, Managing Director of MATTIG & LINDNER GmbH: "We are thrilled to be working with the young research team and expect significant sustainability effects from the new technology."

Ricardo Remus, founder of Sonocrete: "We are very satisfied with how the trial went. Everything worked out as planned and we are grateful that we could do this test here in the plant."

After the successful first real test, further factory trials are planned in the summer of 2021, where the amount of treated cement-water suspension will be significantly increased.

Sonocrete is launching an Early Access program this year, giving selected precast plants the opportunity to use Sonocrete mixers before market launch. Also, Sonocrete will develop a solution for ready-mix concrete soon.

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