Cement stabilized macadam is generally suitable for base or subbase, and its thickness is generally 15 ~ 22 cm. In order to ensure its quality and standardize the construction process, the technical disclosure of cement stabilized macadam construction is specially formulated. This technical disclosure is only a supplement to the chapter "Cement Stabilized Soil" in JTJ034-2000 "Technical Specification for Highway Pavement Base Construction", the technical specifications in drawings and tenders, and the annex to the contract, so all units are requested to jointly implement it. 1.0 material 1. 1 Materials such as cement, stones and sand used for roads must be approved by the supervision engineer. Unauthorized entry and use are not allowed. 1.2 cement: the final setting time is long (preferably more than 6 hours), so 325# slag and ordinary portland cement should be adopted. It is strictly prohibited to use quick-hardening cement, early-strength cement and cement deteriorated by moisture. The choice of cement brand should consider its quality stability, production quantity and transportation distance. Cement shall have a certificate of approval before entering the site every time, and the setting time and label of cement shall be sampled once every 200T 1.3 crushed stone: the crushing value shall not be greater than 30%, and the maximum particle size shall not be greater than 30 mm The particle composition of crushed stone shall meet the requirements of 2# grading in JTJ 034-93. For the convenience of construction, 10-30 mm coarse aggregate, 5- 10 mm medium aggregate and 0-5 mm fine aggregate should be used. The crushing value of coarse aggregate, the screening of various granular materials (mainly to check the particle grading deviation of feed), the plasticity index of fine soil below 0.5mm and the particle content below 0.075mm should meet the requirements in JTJ 034-93. After the above materials enter the site, two samples shall be inspected every 2000m3. 1.4 water: the drinking water of people or livestock can be used for the construction of cement macadam. 2.0 composition design of mixture 2. 1 composition design principle: ① powder content should not be too much. (2) On the premise of reaching the strength, adopt the minimum cement dosage, but not less than 4.0%. (3) improve aggregate gradation, reduce the cement dosage, so that the cement dosage does not exceed 6%. 2.2 The dosage of cement can be prepared in five ways: 4%, 4.5%, 5%, 5.5% and 6%. 2.3 Make 9 samples for each dose (minimum quantity). 2.4 The specimen must be kept moist at the specified temperature (20 2℃) for 6 days, and the unconfined compressive strength test shall be conducted after soaking 1 day, and the average value and deviation coefficient of the test results shall be calculated, and whether RX( 1- 1.645Cv) is greater than Rd (the design strength of this project is 3.5MPa). The design dose should be the minimum dose to meet the strength and should not exceed 6%. 2.5 According to the designed dosage, the influence of delay time on the strength of mixture should be tested, and the delay time to be controlled should be determined through experiments. 2.6 The amount of cement actually used in the construction site increased by 0.5% compared with the designed amount. 3.0 Quality control standard of cement stabilized macadam. 3. 1 Specific testing technical indicators: 3.2 After the completion of rolling in each operation section, all indicators shall be tested immediately, indoor data shall be sorted out and submitted to the supervisor for inspection (within 24 hours), and the strength indicators shall be sent for inspection separately. Supervisors should go to the site to conduct spot checks in time, and notify them in time when problems are found. 3.3 Each subdivisional work shall be graded according to the Standard for Quality Inspection and Evaluation of Highway Engineering in Hebei Province and the Measures for Quality Supervision, Inspection and Evaluation of Highway Engineering in Hebei Province. Engineering scores must be above 97. Those who fail to meet this requirement are not allowed to complete. 4.0 Key points of construction technology 4. 1 The construction technology of cement macadam can be found in 2.5-2.7 of JTJ034-93 Technical Specification for Construction of Highway Pavement Base. 4.2 Subbase detection and soil stripping template 4.2. 1 Before paving cement stabilized macadam base, the subbase must be comprehensively detected, including plane position, elevation, cross slope, width (strength and thickness have been detected) and surface cleaning. If it fails to meet the requirements, reasonable measures should be taken to deal with it (especially where the thickness is insufficient), especially the loose and peeling materials of the subbase should be completely removed, and never. Sprinkle water on the subbase before paving the subbase to keep the surface moist (without water). 1. The extreme degree of compaction is 98% and 94%, with 2 places per lane every 200m. According to mathematical statistics 100%. 2. Smoothness (mm) 83m ruler10ft 95% 3. Width (cm) ≥ 1200ft, four places per 200m 100%. 4. Longitudinal elevation (mm). Every 200m, four sections (left, middle and right elevations) are 85% (including unqualified points within+10 mm-20mm). 5. The transverse slope (%) is 0.3, and every 200m, the fourth section is 95%. 6. Representative thickness-10mm-20mm, one point per 200m lane. The extreme value of 100% is calculated by mathematical statistics. 7. The strength (MPa) is greater than 1 group (9 specimens) every 2000 square meters. According to mathematical statistics, 100% is calculated. 8. The dosage of cement is +0.5% ~ 2%, with 6 samples per 2000m2 1 group. After 2000 square meters, do it once 100% 10. The delay time shall not exceed the specified time. 4.2.2 Before paving cement stabilized macadam, soil forms must be cultivated on both sides, and the width ratio of soil forms should be designed.