您现在所在的位置 :首页 - 新闻中心 > 公司新闻



来源:http://www.ycgjglcl.com/ 日期:2024-02-27


1. Cracks


Cement stabilized crushed stone cracks refer to the subtle cracks that occur on the surface of the cement stabilized crushed stone base mixture after cement solidification and moisture dissipation, and then extend deep and horizontally, penetrating the entire base layer. The width of the cracks is about 1cm~3cm, and the severity can reach 4cm~5cm. The generation of cracks to a certain extent leads to the overall stress state of the board that damages the base layer. If the cracks further develop, reflection cracks will occur, causing cracks or broken boards in the road surface layer.


The causes of cracks in the water stable layer include:


1) The moisture content of cement stabilized crushed stone mixture is much higher than the optimal moisture content, and the dry shrinkage strain of cement stabilized crushed stone base increases with the increase of moisture content of the mixture;


2) Selection of cement varieties;


3) Excessive cement dosage and poor grading;


4) The curing of cement stabilized crushed stone is not timely or standardized;


5) Reason for temperature difference.


Preventive measures:



1) Pay attention to the selection of raw materials to ensure good gradation, and reduce cement dosage while meeting the design strength;


2) Selection of cement: Different types of cement have different dry shrinkage properties. Ordinary Portland cement has very low dry shrinkage, followed by volcanic ash silicate cement, and slag cement has a larger dry shrinkage. Therefore, selecting appropriate cement can to some extent reduce dry shrinkage cracks;


3) Control the amount of fine aggregate, and try to minimize the content of particles with fine aggregate<0.075mm to less than 5%~7%;


4) To control the water content, it is necessary to strictly follow the design of the cement stabilized crushed stone mix ratio to control the water content, making it close to the optimal water content and reducing the risk of cracks caused by improper water use;


5) Reasonably choose the construction time, preferably before the arrival of the summer high temperature season. If construction is carried out during the summer high temperature season, it is advisable to do so in the morning or at night;


6) Strengthening health preservation, as the damage caused by dry shrinkage occurs in the early stages, timely use of geotextile, burlap cloth or film covering for good health preservation can prevent hydration and excessive evaporation of water inside the cement stabilized crushed stone layer mixture, which can cause surface dry shrinkage cracks. If construction conditions permit, timely laying of asphalt surface layer is a good way to reduce dry shrinkage cracks;


7) Adding fly ash (accounting for 10% to 20% of the aggregate weight) to the water stable layer crushed stone base can delay the setting of the water stable layer mixture, increase the freezing ability of the mixture, and improve the deformation performance of the mixture.


2. Unable to extract complete core samples


According to the technical specifications, the age of the cement stabilized crushed stone layer should be between 7d and 10d, and complete drilling pieces should be able to be taken out. However, in reality, some sections of the road cannot take out complete core samples due to looseness. The reason is:


1) Insufficient cement usage results in poor bonding between aggregates and inability to achieve strength;


2) The curing is not carried out in full accordance with the requirements of the specification. After each section of rolling is completed according to the requirements of the specification and the compactness is checked to be qualified, it should be cured immediately. Wet sand should be used for curing. The thickness of the sand layer is 7cm~10cm. Asphalt lotion can also be used for curing. If there is no such condition, the watering cart can also be used for curing. The health period should not be less than 7 days;


3) Poor grading of raw materials for cement stabilized crushed stone layer;


4) The moisture content is inappropriate, so that cement cannot fully hydrate and hydrolyze in the mixture, and the stabilizing effect of cement on crushed stone is not fully exerted, which affects the strength of cement stabilized crushed stone;


5) Improper selection of cement. Ordinary Portland cement, slag Portland cement, and volcanic ash Portland cement can all be stabilized with cement crushed stone, but the initial setting time should be more than 3 hours and the final setting time should be longer (preferably more than 6 hours). It is not advisable to use fast hardening cement, early strength cement, and cement that has been damp and deteriorated;


6) Uneven mixing and insufficient compaction at optimal moisture content, as well as prolonged construction compaction time, have damaged the hardened cement binder and reduced its strength.

  • 上一条:沥青混凝土摊铺施工的标准要求
  • 下一条:沥青混凝土施工过程中,何时适合进行路面密封处理
  • 相关产品: