Plastic Shrinkage Cracking in Cementitious Materials

Plastic shrinkage cracking arises in fresh cementitious materials when rapid moisture loss generates capillary stresses that exceed the developing tensile strength of the cement paste. Typically occurring within the first few hours after casting, these cracks appear as shallow, surface‐parallel fissures and can compromise watertightness, durability and long‐term performance of concrete elements. The driving mechanism involves evaporation from the exposed surface, which promotes a gradient in moisture content and induces self‐desiccation in the upper layer. As capillary pressure builds in the pore network, tensile stresses develop. If the rate of stress growth outpaces stiffening from cement hydration, cracks form. Key factors influencing plastic shrinkage include environmental conditions (temperature, wind speed and relative humidity), mix proportions (water-to-cement ratio, cement type and supplementary cementitious materials), the use of admixtures (such as shrinkage-reducing agents) and reinforcement strategies (fibres or internal curing agents). Mitigation approaches range from optimising bleed water retention and reducing evaporation rates to incorporating fibres or porous aggregates for internal curing. Advances in monitoring, modelling and materials design are converging to offer more reliable control of plastic shrinkage, improving the sustainability and service life of concrete structures worldwide.

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Research from all publishers

Innovative monitoring and predictive modelling have advanced understanding of capillary pressure evolution in early‐age concrete. A multi-scale experimental programme combined high-capacity tensiometry with a deep learning framework to capture capillary pressure up to 2000 kPa and predict its evolution under varying water-to-cement ratios, supplementary cementitious materials and admixture contents. This approach provides a data-driven tool for optimising mixture designs to minimise capillary stresses and delay crack initiation.

Fibre-based mitigation strategies have also been systematically reviewed, comparing synthetic textile fibres and natural cellulosic fibres for shrinkage crack control. Synthetic fibres were shown to reduce shrinkage by up to 50 % through crack-bridging effects, while pre-wetted cellulosic fibres offered 5–30 % reduction via internal curing. The analysis highlights the influence of fibre geometry, dosage and surface treatment on tensile strain capacity and long-term durability.

Recent studies have explored recycled cement paste powder as an internal curing agent. Replacing up to 10 % of cement with porous recycled powder delayed crack onset by one third and reduced principal strains by nearly 30 % through regulated moisture release. Beyond optimal dosages, excessive replacement can elevate tensile strains, emphasising the need to balance internal curing benefits against mixture stability.

Plastic Shrinkage Cracking in Cementitious Materials publication trend

The graph below shows the total number of articles in plastic shrinkage cracking in cementitious materials across all publications each year (not limited to Nature Index journals).

Technical terms

Plastic shrinkage: Early‐age volume reduction in fresh concrete due to moisture loss, leading to tensile stresses and surface cracking.

Capillary pressure: Negative pore water pressure arising from meniscus formation in the pore network as water evaporates.

Self‐desiccation: Internal drying of cement paste caused by hydration reactions consuming pore water and increasing capillary stress.

Shrinkage-reducing admixture: Chemical compound added to fresh concrete to lower surface tension of pore water and reduce capillary pressure.

Internal curing: Use of porous materials or pre-wetted agents within the mix to supply water during early hydration and mitigate shrinkage.

References

1. Novel multi-scale experimental approach and deep learning model to optimize capillary pressure evolution in early age concrete. Cement and Concrete Research (2024).
2. Shrinkage induced crack control of concrete integrating synthetic textile and natural cellulosic fibres: Comparative review analysis. Construction and Building Materials (2024).
3. Influence of Recycled Cement Paste Powder on Early-Age Plastic Shrinkage and Cracking of Cement-Based Materials. Sustainability (2023).