I. Compilation basis
1, technical specification for highway cement concrete pavement construction JTG F30-20032, quality inspection and evaluation standard of highway engineering JTGF80/ 1-2004 3, technical specification for highway engineering construction safety JTJ076/ 1-95 4, 2. Specifications, procedures and standards on which the design is mainly based. The cross slope of pavement 1.0%, and the pavement structure is 300 thick 3:7 lime soil 15cm cement concrete pavement. Cement concrete pavement ***600㎡. Third, the construction preparation
2. In view of the tight construction period, many local interference factors and difficult coordination, the personnel and the construction unit are prepared to send an excellent construction team with rich construction experience, strong coordination ability and good at fighting tough battles, and equipped with enough technical management personnel. According to the engineering quantity and site construction conditions, our project department plans to arrange sufficient personnel and mechanical equipment, and the main technical personnel and labor force are arranged as follows:
3, material preparation and performance test
(1), cement: the physical and chemical properties of cement should meet the national standards, and each batch of cement should have a warranty. And carry out self-inspection according to the frequency required by highway engineering quality inspection and evaluation standards.
(2) Sand: hard, light-resistant, clean, graded according to regulations, with fineness modulus above 2.5. Mud content (washing method) is not more than 3%, organic content (colorimetric method) is not deep and color standard solution.
(3) Gravel: hard, light-resistant, clean, graded according to regulations, the maximum particle size is not more than 3 1.5mm, the graded strength of stone is greater than Grade II, the crushing value conforms to the specifications, the content of needle-like particles is greater than 15%, and the silt content (by scouring method) is not greater than 1%.
(4), according to the construction progress plan, organize all kinds of materials. And to have entered the sand, gravel, cement, steel bar for various performance tests, if there is any does not meet the requirements, should choose another or take remedial measures.
(5) Inspection and adjustment of mixture ratio 1. Inspection and adjustment of workability, sampling and trial mixing according to the design mixture ratio to determine its workability, and if necessary, passing trial paving inspection. If the workability is lower than the requirements, keep the water-cement ratio unchanged and appropriately increase the cement dosage. Add a small amount of materials at a time and repeat the test. Until it meets the requirements. B, strength test, according to the workability meets the requirements of the mixture ratio, appropriate increase or decrease the dosage of cement, configuration of three groups of fresh concrete specimens, and determine its actual density. Determine its strength after reaching the specified age. If the measured strength cannot meet the required matching strength, measures such as increasing cement grade, reducing water cement ratio or improving aggregate gradation can be taken. C, by choosing different water consumption, different water cement ratio, different sand ratio or different aggregate gradation, etc. Through comparison, the economic and reasonable scheme is selected. D, the water content of sand and gravel on the construction site often changes, and it must be measured step by step to adjust its actual dosage.
Fourth, the cement concrete pavement construction scheme
(a), construction lofting
(1), after the acceptance of the pavement base, the construction lofting work will be carried out, with one pile every 20m for the straight section and one pile every 4m for the curved section (the same as the template length). At the same time, central piles such as expansion joints, contraction joints and turning points of tapered slopes should be set, and one side pile should be set at the roadside accordingly.
(2), according to put away the center line and side piles, check the concrete block line of the construction drawing at the scene. For curved segments, the horizontal blocking line must remain perpendicular to the road centerline.
(3), survey lofting must always review, diligent in measurement, diligent in nuclear measurement, diligent in rectification.
(2), pavement base treatment
(1), all crushed, protruding and sunken subbases shall be removed and repaved with plain concrete. At the same time, the expansion joint plates should be horizontally separated, and the expansion joint plates should be aligned with the expansion joints and contraction joints of the pavement up and down.
(2) When the base produces non-expansive temperature shrinkage and dry shrinkage cracks, it should be sealed and waterproof.
(3) When there are large longitudinal cracks at the base, the reasons should be analyzed and effective measures should be taken to stabilize the subgrade.
(4) When the base of some sections needs to be filled in a large area, cement stabilized macadam should be used as the base. (3), install the template
(1), the formwork must have sufficient strength and rigidity (the height of formwork is the same as the thickness of concrete pavement), and the deformed formwork must be corrected before it can be used.
(2), the template should be installed firmly, straight, flat, without distortion, adjacent template connection should be tight, smooth, can not have the phenomenon such as slurry leakage, staggered stubble, staggered height. Template should be able to ensure that the paving, tamping and leveling equipment load travel, impact and vibration without displacement.
(3) The flat curve segment adopts short formwork.
(4) The internal fixed reinforcement and external stressed reinforcement shall not be higher than the formwork, so as to facilitate vibration.