水泥稳定砾石基层防拱胀设计与施工控制浅析

A Brief Analysis on the Design and Construction Control for Preventing Arching Expansion in Cement-Stabilized Gravel Base Courses

摘要: 为有效防治我国西北干旱荒漠地区公路水泥稳定砾石基层沥青路面频繁出现的拱胀病害，本研究对病害的成因进行了系统性分析，并对现有防治措施的局限性进行了深入探讨。基于此，本研究提出了一套优化的基层材料设计与施工控制方法，并通过室内试验与工程应用对其效果进行了验证。成因分析揭示拱胀病害主要由极端温度应力与硫酸盐结晶膨胀共同作用引发，特别是在干旱盐渍土地区，高温与盐化学反应导致基层材料膨胀及强度下降。现有被动防治措施(例如设置胀缝)无法根本解决病害问题，而主动防治措施缺乏系统性的优化设计。本研究提出了四项主动防治策略：(1) 原材料控制：严格控制集料与拌合水的硫酸盐含量，优选低膨胀系数、多破碎面的集料；(2) 低水泥剂量设计：采用大粒径砾石与振动压实工艺，减少水泥用量约0.3%，并预留适当空隙以抑制膨胀；(3) 阻盐隔断层设置：有效阻断盐分的迁移路径；(4) 抗离析施工控制：优选夏秋季进行施工，优化集料级配、拌合工艺、运输摊铺及压实流程。工程实践证明，上述措施能显著提高基层材料的抗拱胀性能，为干旱盐渍土地区路面耐久性设计提供了重要的技术支撑。

Abstract: To effectively prevent the frequent occurrence of arching expansion distress in asphalt pavements with cement-stabilized gravel base courses in the arid desert regions of Northwest China, this study systematically analyzes the causes of the distress and thoroughly discusses the limitations of existing prevention measures. Based on this, an optimized design of base course materials and construction control methods is proposed, and their effectiveness is validated through laboratory tests and engineering applications. The analysis reveals that arching expansion is primarily caused by the combined effects of extreme temperature stress and sulfate salt crystallization expansion, particularly in arid saline soil areas where high temperatures and salt chemical reactions lead to material expansion and strength reduction. Existing passive prevention measures, such as installing expansion joints, fail to address the root cause, while active prevention measures lack systematic optimization. This study proposes four active prevention strategies: (1) Raw material control: Strictly limit the sulfate content in aggregates and mixing water, and preferentially select aggregates with low expansion coefficients and multiple fractured surfaces; (2) Low cement dosage design: Use large-sized gravel and vibratory compaction techniques to reduce cement content by approximately 0.3%, while reserving appropriate voids to inhibit expansion; (3) Installation of salt-resistant isolation layers: Effectively block the migration paths of salts; (4) Anti-segregation construction control: Prefer construction in summer and autumn, and optimize aggregate gradation, mixing processes, transportation, paving, and compaction procedures. Engineering practice has demonstrated that these measures significantly enhance the anti-arching expansion performance of base course materials, providing important technical support for the durability design of pavements in arid saline soil areas.