In the quest for sustainable construction materials, researchers have made a significant stride in understanding how to mitigate drying shrinkage in cement composites incorporating construction waste powder (CWP). This breakthrough could have substantial implications for the energy sector, where the durability of materials directly impacts the longevity and efficiency of infrastructure.
Dr. Shengbo Zhou, from the School of Civil Engineering and Architecture at Suqian University in China, led a study that systematically investigated the drying shrinkage characteristics of cement-CWP composite mortar. The research, published in the journal *Buildings* (which translates to “Buildings” in English), offers practical strategies for enhancing the durability of sustainable construction materials utilizing construction waste powder.
Drying shrinkage, a phenomenon induced by moisture loss under varying environmental conditions, significantly compromises the structural integrity of hydraulic cementitious materials. The utilization of CWP presents a sustainability opportunity, but its impact on shrinkage behavior has remained poorly understood until now.
The study involved a series of experiments on mortar specimens with varying water-to-binder ratios (W/B = 0.45, 0.50, 0.55) and CWP incorporation rates (0, 5%, 10%, 20%). Three curing regimes were employed: outdoor curing, standard curing (20 °C, 95% RH), and outdoor film curing. Drying shrinkage was monitored over time to identify optimal mix proportions and curing conditions for shrinkage control.
Key findings indicate that the optimal CWP content for shrinkage mitigation is 10%. “Excessive CWP (>10%) induces a ‘weak bonding’ effect, leading to an increase in shrinkage due to reduced cohesion,” explained Dr. Zhou. Increasing the W/B ratio to 0.55 effectively reduced shrinkage, with the minimum shrinkage value observed at this ratio. Among curing methods, outdoor film demonstrated superior performance in maintaining moisture and suppressing shrinkage.
Predictive modeling revealed that the logarithmic model accurately captures the nonlinear evolution of shrinkage over time, effectively reflecting the influences of CWP content, W/B ratio, and curing condition. This dual-mechanism regulation of early-age drying shrinkage behavior in cement-based materials by CWP as a supplementary cementitious material establishes a shrinkage prediction model applicable to various mix proportions and curing conditions.
The findings of this research could shape future developments in the field by providing practical strategies for enhancing the durability of sustainable construction materials. For the energy sector, this means more resilient infrastructure that can withstand environmental stresses, ultimately leading to reduced maintenance costs and improved efficiency.
As the construction industry continues to seek sustainable solutions, the insights from this study offer a promising path forward. By optimizing the use of construction waste powder, the industry can not only reduce waste but also enhance the performance of construction materials, contributing to a more sustainable and efficient future.