Sonication Improves Cement Hydration and Strength

Power ultrasound, also known as sonication, is gaining attention as a practical intensification technology for cement and mortar production. Recent research shows that ultrasonic treatment can improve particle dispersion, activate supplementary cementitious materials such as granulated blast furnace slag (GBFS), accelerate hydration, refine pore structure and significantly increase early-age strength.

Higher-Performance Slag-Blended Cement and Mortar With Power Ultrasound

In cement manufacturing and mortar production, one of the major technical challenges is the efficient use of supplementary cementitious materials. Granulated blast furnace slag, or GBFS, is widely used to reduce clinker content and improve sustainability. However, coarse or agglomerated slag particles often react slowly, limiting early strength development. Sonication offers a promising solution: it uses high-intensity acoustic cavitation to disperse agglomerates, fragment particles and increase the number of reactive nucleation sites inside the cement matrix.

Why Sonication Matters for Cement Hydration

The advantage of sonication lies in its ability to act directly on the particle system before and during early hydration. In a cementitious suspension, ultrasonic cavitation generates localized shear forces, microjets and pressure fluctuations. These effects help to break up agglomerates, disperse fine particles and expose fresh mineral surfaces.
For cement and mortar producers, this is important because hydration is highly surface-driven. Better dispersion and smaller reactive particles can increase contact between water, clinker phases and slag particles. This can lead to faster heat release, improved early hardening and a denser microstructure.
In slag-blended systems, sonication is especially relevant because GBFS often requires activation. Ultrasonic particle fragmentation – so-called sonofragmentation – of GBFS particles reduces particle size, particularly the 125–250 μm fraction.

Key Advantages of Sonication in Cement and Mortar Production

Power ultrasound supports industrial cement and mortar production in several ways:

• Improved particle dispersion: Sonication helps disperse cement, slag and fine mineral particles more uniformly in the paste or mortar mix.
• Reduced agglomeration: Ultrasonic treatment can break down particle clusters and may inhibit re-agglomeration during mixing.
• Измельчение зерна: Coarser slag particles can be fragmented into finer fractions, increasing available surface area.
• More nucleation sites: Fragmented GBFS particles can act as nucleation centers for hydration products in the cement matrix.
• Accelerated hydration: Better dispersion and exposed surfaces can increase cumulative heat release and early hardening.
• Higher early strength: Sonicated slag-blended cement pastes can show substantial gains in compressive and flexural strength after only two days.
• Enhanced microstructure: Sonication can increase nanoporosity indicators and modify the pore structure, especially in the 2–10 nm pore range.

Влияние силовой ультразвуковой обработки (УЗИ) на скорость ультразвукового импульса гидратирующих цементных паст

Faster Setting and Early Strength in Precast Concrete with Power Ultrasound

The study “Влияние Power-Ultrasound на текучесть и схватывание портландцементных паст” by Ch. Rößler investigates Portland cement pastes based on CEM I 42.5 R, a w/c ratio of 0.37 and 0.1% polyacrylate superplasticizer. The study usedsa Hielscher UIP1000hd sonicator in flow-through setup to evaluate whether power ultrasound could accelerate hydration, improve fluidity, shorten setting and increase early strength.
The results show that power ultrasound (PUS) accelerates the main hydration period. The temperature curve demonstrate an earlier hydration peak, while the microstructure images after five hours showed larger C-S-H phases in the ultrasound-treated paste than in the reference.
Key advantages achieved:

• Higher fluidity: slump increased from 122 mm in the reference paste to 158 mm after PUS treatment.
• Faster setting: initial set was shortened from 5 h 15 min to 3 h 45 min, and final set from 6 h 45 min to 4 h 30 min.
• Accelerated rigidification: ultrasonic pulse velocity indicated approximately 2 hours faster hardening.
• Higher early strength: mortar prisms produced from PUS-treated cement paste showed increased compressive strength during the first 24 hours.
• Process-economy potential: the authors estimated that an energy input of approximately 10 kWh/m³ cement paste could accelerate setting and early strength by around two hours, with an indicated cost of ≤ 1 Euro/m³ concrete.
• Reduced admixture demand: because PUS increased fluidity, the authors concluded that superplasticizer dosage could potentially be reduced.

These results are especially relevant for precast concrete production, where faster setting and early strength can reduce formwork time, heating demand and production cycle times.

Vicker’s Hardness and Elastic Modulus of C + S pastes prepared conventionally and with the use of Power Ultrasound after 28 d.
Graphs and study: ©Lisowski et al. 2024.

Stronger Early Strength in GBFS-Blended Cement Paste

One of the most important findings for industrial cement and mortar applications is the improvement in early-age strength. According to Lisowski et al. (2024), pulsed ultrasound treatment of cement pastes containing 20% deposited GBFS produced considerably higher strength after two days. The reported increases reached up to 132% in compressive strength and 58% in flexural strength.
This is highly relevant for precast concrete, dry-mix mortar, repair mortars, tile adhesives and other cementitious products where early demolding, early handling strength or rapid construction progress is economically important.
The strength increase was correlated with increased cumulative heat of hardening, suggesting that sonication does not merely improve physical dispersion but also intensifies early hydration. In practical terms, this means that power ultrasound could help producers use slag more effectively without sacrificing early performance.

SEM images of Cement-GBFS paste specimen C + S comparing the effect without and with Power Ultrasound at 28d.
Images and study: ©Lisowski et al. 2024.

Sonofragmentation Makes Coarser Slag Fractions More Useful

A particularly valuable result is the effective activation of relatively coarse GBFS fractions. The study found that the 125–250 μm slag fraction delivered the best early-age and 28-day strength when combined with deposited slag particle separation and power ultrasound treatment.
This is industrially significant because grinding slag to very fine sizes is energy-intensive. If sonication improves the reactivity of coarser or deposited GBFS fractions, producers can reduce grinding demand, improve raw material efficiency and make better use of secondary material streams.

Industrial Relevance: Power Ultrasound for Efficient Cement and Mortar Production

For industrial cement and mortar producers, sonication offers several strategic advantages. It can be integrated as a process-intensification step during slurry preparation, binder activation, admixture dispersion or high-performance mortar mixing. The technology is especially attractive for products that depend on fine particle distribution, fast hydration and optimized use of supplementary cementitious materials.

• Higher early strength without increasing clinker content
• Better activation of GBFS and other supplementary cementitious materials
• Improved use of coarse or deposited slag fractions
• Reduced agglomeration in cementitious suspensions
• More consistent hydration and hardening behavior
• Potential reduction of grinding intensity for selected slag streams
• Improved performance of low-clinker and low-carbon cement formulations

This makes sonication highly relevant for the production of sustainable cement, slag cement, high-performance mortars, precast elements, repair materials and specialty construction products.

Sonication as a Tool for Low-Carbon Cement Technology

The cement industry is under pressure to reduce CO₂ emissions, and lowering the clinker factor is one of the most direct routes. However, higher replacement levels with GBFS, fly ash, calcined clay or other supplementary cementitious materials can slow down early strength development. Power ultrasound may help overcome this bottleneck by improving dispersion, activating particles and accelerating early hydration.
Sonication can make slag-blended cement pastes more reactive and mechanically stronger, especially when the process is optimized for particle size fraction and treatment time. That combination is highly relevant for industrial-scale binder engineering.

Hielscher Sonicators for Enhanced Cement Hydration, Strength and Slag Reactivity

Hielscher inline sonicators are a powerful tool to improve cement hydration and strength, particularly in slag-blended cementitious systems.
For industrial cement deagglomeration and dispersion, Hielscher high-performance sonicators provide the intense cavitational shear required to break cement, slag and mineral filler agglomerates into finely dispersed particles, improving particle wetting, surface activation and homogeneity in cementitious slurries. Hielscher systems are available from bench-top and pilot scale to robust high-throughput production systems, including high-power inline sonicators for continuous processing of cement grout and mineral suspensions. This makes process development directly scalable from R&D to full industrial throughput. By eliminating or reducing the need for grinding media, ultrasonic deagglomeration simplifies processing, minimizes contamination risks and reduces cleaning effort, while delivering reproducible dispersion quality. For cement and mortar manufacturers, Hielscher sonicators therefore offer a practical route to more uniform binder systems, improved hydration kinetics, better use of GBFS and other supplementary cementitious materials, and higher-performance low-clinker formulations.

The table below gives you an indication of the approximate processing capacity of our power ultrasound systems:

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