A study on drying shrinkage properties of PVA fiber reinforced coal gangue fine aggregate concrete

• Coal gangue fine aggregate replacement rate elevation boosts drying shrinkage, with 180-d strain rising by 91.3% at 100% replacement. • In 100% coal gangue concrete, a 1.0% dosage of PVA fibers reduces 180-day shrinkage by 16.6%. • Based on the drying shrinkage model MC2010, a drying shrinkage prediction model suitable for PVA fiber-reinforced coal gangue fine aggregate concrete was derived. Additionally, correction factors for coal gangue fine aggregate and PVA fibers were introduced. This study systematically investigates the long-term drying shrinkage behavior of polyvinyl alcohol (PVA) fiber reinforced coal gangue fine aggregate concrete (CGFC) through an experimental and analytical approach. An 180-day drying shrinkage test was conducted, considering two key variables: (1) coal gangue fine aggregate replacement rates and (2) PVA fiber dosages. We analyzed the synergistic effects of these parameters on drying shrinkage and evaluated three widely used drying shrinkage prediction models EC2, B4, and MC2010 to develop a tailored predictive model for PVA-CGFC. The experimental results demonstrate that increasing the coal gangue replacement rate leads to a substantial increase in drying shrinkage. While PVA fiber mitigates concrete shrinkage at low dosages, its effectiveness diminishes at higher concentrations. A comparative model-fitting analysis was conducted to assess the predictive accuracy of various models for PVA-CGFC. The MC2010 model was found to offer the most accurate predictions, and based on this model, an enhanced predictive equation was developed. This equation incorporated correction factors that considered coal gangue replacement rate and PVA fiber dosage, thereby leading to an improvement in fitting accuracy.