According to the requirements of the technical specifications, the Jinan cement stabilized macadam layer has an age of 7d~10d, and it should be able to take out complete drill pieces. However, the actual situation is that some sections cannot take out complete core samples because they are loose. What is the reason?
1) The cement consumption is too small, resulting in poor cementation between aggregates and failure to reach the strength;
2) If the curing is not carried out in full accordance with the specification requirements, the curing shall be carried out immediately after the compaction of each section is completed according to the specification requirements and the compactness is checked to be qualified. It is better to use wet sand for curing. The thickness of the sand layer is 7cm~10cm. Asphalt lotion can also be used for curing. If there are no conditions mentioned above, the watering cart can also be used for curing. The curing period should not be less than 7 days;
3) The raw materials of cement stabilized macadam are poorly graded;
4) The water content is not appropriate, so that the cement cannot be fully hydrated and hydrolyzed in the mixture, and the cement does not play a role in stabilizing the crushed stone, affecting the strength of cement stabilized crushed stone;
5) Improper cement selection. Ordinary Portland cement, slag Portland cement and pozzolanic Portland cement can be used to stabilize crushed stone, but the initial setting time shall be more than 3h and the final setting time shall be longer (preferably more than 6h). Fast hardening cement, early strength cement and cement that has been damped and deteriorated should not be used;
6) Uneven mixing, insufficient compaction under good water content, and too long construction rolling time destroy the hardened cement gel and reduce its strength.
1) In terms of raw materials, each batch of cement can only be used after passing the inspection; Crushed stone shall meet the grading requirements, and the large material diameter shall not exceed 31.5mm. Unqualified materials shall not enter the site;
2) The mixing process shall be improved to avoid segregation as much as possible. The construction personnel shall strengthen the control of the cement agent, and timely improve and handle the problems found;
3) Shattered measuring instruments shall be sent to the Measurement Quality Inspection Center for verification before commencement to ensure the accuracy of weighing;
4) Small feeder trucks shall be avoided during transportation, and the mixture shall be covered to reduce evaporation of water during transportation.
The occurrence of these quality problems of cement stabilized macadam base requires operators to strictly control each process. Only in this way can the quality of cement stabilized macadam be guaranteed and the occurrence of diseases be avoided. More relevant content will come to our website http://www.ycgjglcl.com Ask and understand!