Construction Technology of Concrete Faceplate in Municipal Engineering Project 1The steel formwork should be straight and flat, and a supporting device should be set at one place per lm.The thickness of straight part of wood formwork should not be less than 50 mm. Support should be provided every 0.8-1 m, bend part 15-30 mm, and support should be provided every 0.5-0.8 M. 2The installation of formwork should be stable, straight, flat and without distortion, and should not be dislocated; the formwork should not be embedded in the basic excavation trench.Brush release agent or isolator after inspection. 3Paving and Vibration When a three-roll shaft unit lays concrete surface, the diameter of the roll shaft matches the paving thickness. It must be equipped with a row vibration tamper with an inserting vibration tamper group.The vibration tamping beam can be used when it is less than 150 mm.Within the length of a working unit, forward vibration and backward static rolling should be adopted. Reasons for cracks in surface layer of three-roll shaft are analyzed: machine, slitting, maintenance and open traffic. (1) Construction method: The diameter of three-roll shaft unit should match the thickness of paving layer, control paving speed, and vibrate with row vibrator; (2) Seam cutting problem: determine the mode and depth of seam cutting according to the temperature difference between day and night; (3) Maintenance problems: Maintenance time may be too long. Maintenance time should not be less than the time required for concrete to reach 80% of the design flexural strength, generally 14-21 days.Only when the design bending strength reaches 100%, can the traffic be opened. (2) When paving with track paver, the minimum paving width should not be less than 3.75m, and the suitable paver should be selected, and the slump should be controlled in the range of 20-40mm.The thickness of the panel exceeds 150 mm and the slump is less than 30 mm. Vibration must be inserted. (3) When the manual spreading coefficient is 1.1- 1.25 and the spreading thickness reaches 2/3, the steel brazing in the die is pulled out.The thickness of the lower layer is 3/5 of the total thickness when paving twice. 4Joint The expansion joints of ordinary concrete pavement should be reinforced by steel brackets, expansion joints plate and force transfer rod.Expansion joints should be perpendicular to the center line of the pavement; the seam walls must be perpendicular; the seam width must be consistent, and slurry must not be connected in the seams.The upper part of the joint is filled with seam filling material, the lower expansion joint plate and the installation of force transfer rod. (2) There are two methods of fixing and installing the force transfer rod.One is the installation method of the fixed force transfer rod of the end wooden formwork, which is suitable for the expansion joint of the concrete slab in discontinuous pouring.The other is the installation method of the fixed transmission rod of the support, which is suitable for the expansion joint of the concrete slab when it is continuously poured. 5The transverse shrinkage joints are constructed by a slitting machine. According to the temperature difference between day and night, the slitting mode can be divided into three types: all hard slits, soft-hard combined slits and all soft slits. (1) Temperature difference < 10 C, 1/4-1/5 plate thickness of hard cutting seam; (2) Temperature difference 10-15 C, soft-hard combined cutting, depth not less than 60 mm, less than 1/3 of the hard cutting; (3) Temperature difference > 15 C, all soft-cut, depth (> 60 mm), non-disconnected depth to no less than 1/4 plate thickness. (4) The longitudinal and transverse shrinkage joints are cut at the same time, and the width of the seam is 4- 6 mm.Longitudinal construction joints have flat joints, entrance joints and other forms.For the longitudinal contraction joint inserted into the tie rod, it should not be less than 1/3-1/4 of the thickness of the plate and not less than 70 mm. Simple memory: hard cut 1/4-1/5, soft-hard combination and soft cut 1/3, 1/4, complementary cut (> 60); insert pull rod 1/3-1/4, (> 70). 6Maintenance: spraying curing agent or moisturizing cover; not using water curing; using heat preservation curing when the temperature difference between day and night is greater than 10 or the average temp

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