What is the construction plan for the comprehensive environmental management project in the old community? What are the technical measures? Please read the article by the editor of Zhongda Consulting.
Rolling: Use a grader for leveling first, and then use a light roller to roll it over again. After checking to reach the loose pavement level, compaction can be done again.
6 For pavement construction, calculate the amount of earth that needs to be excavated based on the designed elevation of the longitudinal section. Level the earth after the excavation is in place. Use a vibrating roller to perform static pressure once and lightly vibrate twice to ensure the pressure of the roadbed. Reality.
6.1 Construction of fly ash gravel base
The road base of this project is 28cm thick fly ash gravel, which is constructed using the factory mixing method. There are 2 construction teams, each team is equipped with 1 road roller.
6.1.1 Construction preparation
Make measurement preparations according to the design, place piles on the inspected road trench, cultivate shoulder soil on both sides of the construction section, and clear the surface of the working surface If there is floating soil, water, etc., sprinkle water on the surface to moisten it.
6.1.2 Construction of test section
A test section with a length of 100m-200m must be paved before construction. The number of mixing passes, compaction method, mechanical combination, process, loose paving coefficient, number of rolling passes, optimal moisture content, etc. are determined through the test section as the basis for base construction. After the test section passes the inspection, it will be used as part of the permanent base layer, otherwise it will be excavated.
6.1.3 The fabric is layered according to the process determined by the test section, using the horizontal fabric method. When fabricating, each section should be fully clothed so that it is better to scrape rather than mend.
6.1.4 Rolling: First use a grader for leveling, and then use a light roller to roll it again. After checking to reach the loose paving elevation, compaction can be carried out again. Rolling follows the principles of starting from the roadside to the middle of the road, light first and then heavy, vibrating the roller strongly and then vibrating lightly, compacting the lower part first and then compacting the upper part, and rolling at low speed. Avoid shifting, peeling and pressure leakage. The part of the surface of the subbase that is higher than the design elevation must be scraped off, and the scraped lime gravel must be swept out of the road. Partially lower than the elevation cannot be patched, and must be eradicated and re-paved.
6.1.5 Joints: The connection between two working sections constructed on the same day shall be treated by the lap joint method, and the connection between two working sections constructed on the next day shall be treated as a working joint.
6.1.6 Health care: The curing period will begin after rolling. During the curing period, straw curtains or other materials approved by the supervision should be used to cover the curing period to keep the base layer moist and prevent the surface moisture of the limestone gravel from evaporating. cracking. Vehicles are not allowed to pass during the health care period, which lasts for 7 days. Continue to cover after the curing period is over, and do not expose it to the sun. Take antifreeze measures in winter.
6.2 Pavement lower sealing layer
6.2.1 Construction preparation: Use 6-8 people to clean the surface of the lime gravel base layer, and try to make sure that the aggregate particles of the lime gravel base layer can be partially exposed.
6.2.2 Construction of test section: Before the formal construction of the lower seal layer, a test section with a length of not less than 300m shall be constructed. Determine the emulsified asphalt spreading quantity, spreading technique, aggregate quantity and aggregate spreading technique.
6.2.3 Sealing layer construction
6.2.3.1 Use asphalt spreading trucks to spread evenly. Necessary measures should be taken to avoid excessive spraying at the start and end. Local excessive spraying should be manually eradicated; areas where spraying is missed should be resprayed manually. The aggregate spreading is completed before the emulsified asphalt surface is demulsified, and the aggregate is spread manually to ensure even distribution.
6.2.3.2 Use a 6-8t double steel wheel roller to roll it twice, and do not crush the aggregate.
6.2.3.3 After the crushing, traffic will be closed according to regulations.
6.3 Construction of medium and coarse-grained asphalt surface layers
6.3.1 Inspection and cleaning of the lower bearing layer
Check the integrity of the lower sealing layer or adhesive layer before construction properties, and the deficient parts shall be repaired according to construction requirements. Clean the lower bearing layer to remove surface contaminants and flush with water if necessary.
6.3.2 Paving the test section
Before constructing each layer of the asphalt surface layer, a test section should be made first. The length of the main line straight section of the test section should not be less than 200m.
6.3.3 Determine the mixing speed, mixing quantity, mixing time, and mixing temperature of the mixer through trial mixing, and verify the mix ratio design of the asphalt concrete mixture.
6.3.4 Determine the treatment method of construction joints and the loose paving coefficient of various asphalt surface layers through trial paving. Determine the mineral mix ratio and whetstone ratio, paving temperature, paving speed, compaction sequence, rolling temperature, rolling speed and number of passes for formal production.
6.3.5 After all indicators of the test section pavement meet the requirements of the specification, it can be used as part of the permanent pavement. Otherwise, it will be excavated.
6.3.6 Mixing of asphalt mixture
Strictly control the heating temperature of asphalt and aggregate and the exit temperature of asphalt mixture. The aggregate temperature is 10-20°C higher than that of asphalt. After the hot mix product is stored in the storage silo, its temperature shall not drop by more than 5°C, and the storage time in the storage silo shall not exceed 24 hours. The discharge temperature of asphalt mixture should be controlled within the range of 150℃-165℃. Mixtures higher than 170℃ or lower than 145℃ should be discarded. Send a dedicated person to visually inspect the uniformity of the mixture and analyze abnormalities in a timely manner.
6.3.7 Transportation of asphalt mixture: Use a digital display plug-in thermocouple thermometer to detect the temperature of the asphalt mixture at the outlet and on site.
The material transport truck is equipped with tarpaulin covering facilities to keep warm and avoid rain or to avoid polluting the environment. During the continuous paving process, the material transport truck should stop 10-30cm in front of the paver and must not touch the paver. During the unloading process, the transport truck is in neutral and pushed forward by the paver.
6.3.8 Paving of asphalt mixture
6.3.8.1 Continuous and stable paving is the most important measure to improve the smoothness of the road surface. The paving speed of the paver is adjusted and selected according to the output of the mixer, the supporting construction machinery, the paving thickness, and the paving width at 2-3m/min to achieve slow, even, and uninterrupted paving.
6.3.8.2 The surface layer uses a mobile automatic leveling reference device to control the paving thickness. Automatic leveling systems are installed on both sides of the paver machine. Two staff members are assigned to monitor the thickness at any time during paving to facilitate timely adjustments. Paving thickness.
6.3.8.3 When the paving encounters rain, stop the construction immediately and remove the uncompacted mixture. Mixtures that have been exposed to rain must be discarded and shall not be loaded into the paver for paving.
6.3.9 Compaction and shaping of asphalt mixture
6.3.9.1 Compaction of asphalt mixture is an important link to ensure the quality of asphalt surface layer. The construction technology determined according to the test section Choose a reasonable combination of road rollers and rolling steps. In order to ensure compaction and smoothness, the initial pressing should be carried out at a higher temperature after paving without causing movement or cracking of the rolled mixture.
6.3.9.2 The road roller rolls at a slow and even speed. The suitable rolling speed of the road roller varies with the initial pressure, re-pressure, final pressure and the type of road roller.
6.3.9.3 In order to avoid the mixture being pushed and hugged during rolling, the driving wheel should face the paver during rolling; the rolling route and direction should not change suddenly. For dead corners, edges, joints, etc. that cannot be compacted by the roller, use a small vibratory roller or a hand-held vibratory roller to compact them while they are hot. The turning back of the road roller shall not be on the same cross-section.
6.3.9.4 No rollers or other vehicles shall be parked on the asphalt concrete layer that has not yet cooled down and shall be prevented from being scattered on the asphalt layer.
6.3.9.5 Clear signs are set up in the initial pressure, re-pressure and final pressure stages to facilitate driver identification. Set up special inspection posts for the thickness of loose paving, rolling sequence, number of rolling passes, rolling speed and rolling temperature.
6.3.9.6 Construction vehicles can be allowed to pass 24 hours after compaction is completed.
6.3.10 Treatment of construction joints
6.3.10.1 Longitudinal construction joints: Longitudinal joints using the echelon joint paving method of two pavers, which have been Leave a width of 10-20cm in the part of the paved mixture that is not rolled as the rear elevation datum, and there is about 5-10cm of overlapping paving layers. Roll across the joints at the end in the form of thermal joints to eliminate seam marks. . The longitudinal seams of the upper and lower layers are staggered by more than 15cm.
6.3.10.2 Transverse construction joints: All flat joints shall be used. Use a 3-meter straightedge in the longitudinal direction, with the straightedge at the end of the paving in a cantilever shape. Determine the joint position at the point where the paving layer and the straightedge are out of contact, cut it with a sawing machine and then remove it. When continuing to pave, clean the mortar left when sawing the joints, apply a small amount of adhesive layer asphalt, and start paving from behind the joints with the paver screed; use a double-steel wheel roller for lateral compaction during rolling. Really, gradually move across the joints from the previously paved road to the new pavement layer.
6.3.11 Issues that require greater attention during the construction process
6.3.11.1 The floor where various mineral materials are stacked must be hardened and have a good drainage system to avoid material contamination ; Various types of materials should be separated by walls to avoid mixing with each other.
6.3.11.2 Fine aggregates and mineral powder must be covered. Moisture of fine materials will affect the feeding quantity and mixer output.
6.3.11.3 Each mixer is designed with a production mix ratio to ensure the stability of the mix.
7 Masonry Project
7.1 Brick Watering
Clay bricks must be watered and moistened one day before masonry. Generally, water invades 1.5cm from the four sides of the brick. It is recommended that the moisture content is 10-15%. Dry bricks should not be used for normal temperature construction. Brick walls with a saturated moisture content should not be used during rainy season.
7.2 Mortar mixing
The mortar mix ratio should be weight ratio, the measurement accuracy level is recorded as plus or minus 2%, and the sand and ash paste should be controlled within plus or minus 5%. Machinery should be used Stir for moderate amounts of time.
7.3 Masonry
7.3.1 Before laying the foundation wall, the surface of the base cushion should be cleaned and moistened with water. Then, the height of the corner should not exceed five layers of bricks each time.
7.3.2 When the foundation is built at a large angle to the wall, the axis and edge lines must be checked to ensure that the position of the foundation wall is correct and that the number of layers in the corner is consistent with the number of the poles.
7.3.3 The height of the corner of the foundation wall should not exceed five skin bricks at a time, and they should be hung flat and straight to ensure that the wall is horizontally and vertically. The wall should be hung with wires, and the 24-wall backhand Hanging wires should be hung on both sides above the 37 wall.
7.3.4 If the foundation cushion has different elevations or has partially deepened areas, the masonry should be built from the lower part upwards, and the through lines should be checked frequently to keep the masonry straight and smooth to prevent it from forming a screw wall.
7.3.5 The upper and lower joints of the masonry are staggered, and there are no continuous joints of 4 skin bricks at any place.
7.3.6 The mortar of the mortar joints of the brick masonry joints is dense, the joints and bricks are straight, and the thickness of the horizontal mortar joints at each joint is not less than 5mm or there are no more than 5 translucent defects.
8 Coating surface project
8.1 Exterior wall base treatment:
1:3 cement mortar (or polymer cement mortar) repair and smoothing (including grating joints) ), and then remove the ash, lumps and other debris on the surface of the base layer with a shovel and chisel. Wire brush away loose surfaces. If the surface is stained with oil, wipe it clean with gasoline. Then use putty to smooth out the uneven and uneven surfaces. After drying, smooth it with No. 1 coarse sandpaper.
8.2 Fully scrape the putty and polish it once: All tiny blisters and shrinkage joints need to be scraped thoroughly to ensure they are dense, flat, and have neat lines, corners, and edges. At the same time, the scraper should be scraped horizontally along the wall as thinly as possible without leakage, and the joints should not be rubbed, and be careful not to contaminate doors, windows and other surfaces. After the putty is completely dry, wrap a flat wooden board with No. 1 sandpaper and polish the putty residue and uneven areas. Pay attention to using even force to protect the edges and corners.
8.3 The second pass of putty polishing: The second pass of putty is the same as the first pass of putty, but the scraping direction of this pass of putty and the previous pass of putty and the previous pass of putty should be perpendicular to each other, that is, it should be along the wall. Scrape the surface vertically until the wall surface is fully scraped and polished until it is smooth and smooth.
8.4 The first coat of paint: Before applying the first coat of paint, the surface of the base layer must be cleaned and any floating powder removed. When painting, you should use a brush. The order of painting is generally from top to bottom, from left to right, first horizontally and then vertically, first edges, corners, small surfaces, and then large surfaces. The top and bottom work at the same time and cooperate with each other to avoid rubbing and overlapping of brushes.
The above is collected and compiled by Zhongda Consulting
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