1. Mechanical and Impermeability Properties of Polymer Grouting Materials for Hydraulic Expansion Joints.
- Author
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Dong Yan, Xiaofei Li, Mengchen Xiao, Lei Zhang, and Inchen Chen
- Subjects
HYDRAULIC structures ,WATER leakage ,MAGNESIUM oxide ,WATER pressure ,STRENGTH of materials - Abstract
Among the water leakage issues in hydraulic tunnels, the issue of water leakage through expansion joints accounts for nearly 90%, making it the primary defect of hydraulic tunnels and posing serious safety hazards to hydraulic structures. To address the issue of water leakage through hydraulic expansion joints, this study investigated a polyurethane polymer grouting sealing material. Traditional sealing and leaking stoppage materials used for hydraulic expansion joints had drawbacks, such as high viscosity, excessive rigidity resulting in the failure to adapt to the deformation of expansion joints, and poor adhesion to concrete. The mechanical properties and impermeability of grouting materials prepared by blending polyurethane with epoxy resin were analyzed through orthogonal and single-factor tests. The excellent sealing and leaking stoppage effects of polyurethane polymer were demonstrated and the optimal mix ratio of the polymer grouting material was determined. Results show that, (1) the gel formed by the reaction of polyurethane and epoxy resin has good mechanical properties. (2) The compressive strength of the grouting material continuously increases with the increase in the dosage of the curing agent and reaches the maximum of 0.98 MPa. The tensile strength of the grouting material initially increases then decreases, and the maximum value is 0.7 MPa. The elongation at break is negatively correlated with the dosage of the curing agent, and the minimum value is 54%. (3) Magnesium oxide can improve the mechanical properties and setting time of the grouting material. The setting time of the grouting material initially increases then decreases with the increase in the dosage of magnesium oxide. Moreover, the compressive strength increases with the increase in the dosage of magnesium oxide, and the swelling rate upon contact with water decreases with the increase in the dosage of magnesium oxide. The comprehensive property is optimal when the dosage of magnesium oxide is 1%. (4) With the increase in the dosage of magnesium oxide, the water pressure at which the grouting material permeates the specimen increases then decreases, and the maximum water permeation pressure is 0.5 MPa. This study provides a good reference and basis for assessing the impermeability of polyurethane polymer grouting materials. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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