(1) Overview
Bid A of Mei Dan Road Road Project undertaken by Hefei Municipal Engineering Group Co., Ltd. has a total length of 2 102m (the road pile number is 0+000 ~ 2+ 102), and the BRT base is 5% cement stabilized macadam with a thickness of 36cm. The expressway base is 36 cm thick 5% cement stabilized macadam. The auxiliary road base is 36cm thick 5% cement stabilized macadam. 5% cement stabilized macadam slow-moving comprehensive base, thickness 18cm. This project is the first main road leading directly to Binhu New District, and it is also one of the key projects of the municipal government. This road has the characteristics of wide road, large engineering quantity, complex pipeline, tight construction period, heavy task and great construction difficulty. The raw materials of cement stabilized macadam are mainly cement and macadam. The quality of raw materials, mix design and construction scheme are important factors to ensure the quality of cement stabilized macadam structure. Therefore, the cement stabilized macadam base requires higher construction technology and organization. According to the actual situation of the construction site, this detailed special construction scheme is put forward to guide the construction.
(2), the construction plan
It is planned to complete the paving and rolling of cement stabilized macadam (the area with construction conditions) on February 25th, 65438. The total quantity of cement stabilized macadam is 258546M2.
(3), construction process
Raw material test → test mixture ratio → batching → check cement dosage and water content → mixing → transportation → measuring and lofting → paving → initial plastering → voltage stabilization → fine plastering → rolling forming → maintenance.
(4), bearing layer construction preparation
1, recheck the elevation, width, vertical and horizontal slope, slope and flatness of lime-fly ash macadam base. No loose materials and weak points.
2, bearing layer should be thoroughly cleaned, and the right amount of water, keep the bearing layer moist.
(5), construction lofting
Re-survey the center line on the lime-fly ash macadam base which has been cleaned and formed and accepted by the supervision engineer. Set one pile every 20m for straight line section, one pile every 10m for flat curve section, and one indicator pile 0.5m outside the edge of pavement for horizontal measurement. On the indicator piles on both sides, according to the design elevation, measured elevation and test section, the accurate loose laying coefficient is obtained, and the steel wire is pulled at the loose laying position indicated by the indicator pile.
(6) Testing
Select the source of materials before they are put into use. High-quality macadam aggregate shall be selected for the macadam, and the maximum particle size of macadam shall not exceed 31.5 mm. The macadam must be composed of 3-4 kinds of aggregates with different sizes and specifications, and the ingredients shall be divided into warehouses. Grading shall be carried out according to 15-30mm, 5- 15mm, 0-5mm, and then mixed in proportion. Natural graded macadam shall not be used directly. Gravel should have sufficient strength and good particle shape. Crushing value of macadam aggregate at the base is ≤30%, and needle content is ≤30%. Ordinary portland cement shall be used as the cement, and quick-hardening cement, early-strength cement and cement deteriorated due to moisture shall not be used. Construction water should be clean and free of harmful substances. The dosage of cement is 5% ~ 5.5%, and the water cement ratio is 0.3 ~ 0.32.
Before construction, the central laboratory of the construction site shall carry out the mixture ratio scheme test according to the mixture ratio recommended by the specification or design, and report it to the supervisor for approval. The 7-day unconfined compressive strength of the mixture specimen shall be no less than 3.5Mpa for the upper layer, no less than 98% and no less than 3.0 Mpa for the lower layer, and no less than 97%. The mixture ratio should be approved by the supervision engineer or the owner (representative) before the formal construction.
Test section: Select the test section with the length of 100m, and carry out on-site paving and compaction test according to the mixture ratio approved by the engineer. In order to check whether the construction equipment used can meet the construction method, material preparation, mixing, paving and compaction organization and the adaptability of one-time construction length. It is planned to adopt different compaction thicknesses in the test section to determine its dry weight and water content, as well as the compaction coefficient, compaction times and compaction procedures when the mixture reaches the optimal water content.
Through the trial mixing in the test section, the method and system to keep the gradation stable and control the mixture production are obtained. Through trial paving, technical supporting measures are put forward to reduce segregation, facilitate paving, avoid early shrinkage cracks and give consideration to flatness and compactness requirements.
(7), mixing
Cement stabilized macadam is mixed with stabilized soil plant mixing equipment. Aggregate must be mixed in warehouses, and aggregate, cement and water must be automatically measured to ensure accurate dosage. The mixing station is equipped with three WBS300 mixture mixing stations, which are responsible for mixing the mixture, working 16 hours a day to ensure the supply of the mixture as scheduled. When mixing, mix the ingredients according to the mixture ratio determined by the test. In the process of mixing, the amount of water added is slightly greater than the optimal water content, and it will be transported away as soon as it is mixed. Debug the machine repeatedly before mixing to make the mixer run normally and mix evenly. Mix the ingredients in proportion, add water according to the weight ratio, and record the time and amount of adding water when mixing. When mixing, the water content of the mixture is 0.5%- 1.0% higher than the optimum water content to compensate for the water loss in the subsequent process; The measurement of cement actually used in the construction site can be appropriately increased compared with the dosage determined in the indoor test, and the maximum dosage is not more than 0.5%, and the dosage of cement is strictly in accordance with the design requirements. The mixture produced by the mixer is guaranteed to be very uniform and the color is consistent, and there are no gray stripes, flower strings and flower surfaces, and there are no "nests" of cement and gravel particles. When materials that are not fully mixed are found, they need to be remixed before they can be used or taken out for stacking.
(8), mixture transportation
The mixed mixture shall be transported to the site for paving as soon as possible, and the truck shall be loaded evenly. The mixture is transported by 20 15t dump trucks. When transporting, if the transport vehicles want to pass through the paved road section, the speed must be slow to reduce uneven rolling or rutting. Our project department will assign special personnel to direct the unloading of transport vehicles to ensure safe production and make corresponding records. The time from adding water to the mixer for the first time to completing the compaction work is controlled at 3 ~ 4h hours. The configuration of the mixture transport vehicle should be comprehensively determined according to the transport distance, road conditions, paving capacity and other factors to meet the paving requirements. It is generally advisable to use 1 ~ 2 vehicles at the paving site. The mixture on the car is covered with plastic film to prevent water evaporation during transportation, and the loading height is kept uniform to prevent segregation. Dump trucks transporting the mixture should pass evenly on the entire surface of the completed paving layer, and should slow down to reduce uneven rolling or rutting.
(9), mixture paving and forming
When paving the cement stabilized macadam base, the water content of the mixture should be 0.5% ~ 1.0% higher than the optimal water content to compensate for the water loss during paving and rolling. The truck stops in front of the paver 10 cm-30 cm, and the paver shirks, discharging while advancing, and the discharging speed is coordinated with the paving speed.
The mixture is paved with pavers, and there are two pavers. When paving the mixture with a paver, the forward speed of the paver should be coordinated with the feeding speed, and the paving speed should be controlled at 3-4m/min. The paving speed should be even and continuous, otherwise the flatness will be greatly affected.
During construction, surveyors will be sent to detect the elevation after paving at any time, and remedial measures will be taken immediately if there is any abnormality.
Designate a special person to use the mixed cement stabilized macadam. After paving, manually fill the parts with concentrated coarse materials on the surface to make the surface uniform. If the local moisture is not suitable, it should be dug out and filled with qualified materials. Excess waste shall not be discarded on the roadside, and shall be transported away from the site by trolley at any time.
(10), mixture rolling
After the mixture is spread and shaped for about 50m, it can be rolled as a rolling section. The straight line segment rolls from the edge to the center, and the superelevation segment rolls from the inside to the outside. Each rolling shall overlap with the previous rolling 1/2 wheel width. First, use a smooth roller to stabilize the pressure at a rolling speed of 1.5-2KM/h, then use a heavy vibratory roller to vibrate for 3-4 times at a rolling speed of 2.5-3KM/h, and finally use a light roller to flatten it. Such that the entire thickness and width of each layer are completely and uniformly compacted to the specified density. After compaction, the surface should be smooth, without wheel tracks or bulges, cracked washboards and loose peeling, and the degree of compaction should reach 98% of the maximum dry bulk density determined by heavy compaction test. When rolling, the surface of cement stabilized macadam should always be wet. If the surface water evaporates quickly, sprinkle a small amount of water in time. It is forbidden for the roller to turn around or brake suddenly on the completed or rolling section. If you need to turn around, you should cover 10cm thick gravel to ensure that the base surface is not damaged. In rainwater, sewage and other parts that are not easy to be crushed in place, such as poles, pipeline inspection wells, etc., fully compact with small machines and tools.
(1 1), health
After the completion of rolling, water should be sprayed immediately for curing and covered with plastic film. The number of sprinklers per day shall be subject to keeping the surface of the grass-roots unit moist, and the curing period shall not be less than 7 days. Traffic should be closed during health care. If traffic cannot be closed due to special reasons, the speed should be limited below 15km/h, but heavy vehicles are strictly prohibited. Three days before curing, choose sprinkler to spray water, and pay attention to the spraying angle to avoid washing cement stabilized macadam and causing local pits and grooves.
(12) sampling and testing
During the construction process, the water content, cement and seven-day unconfined compressive strength of the mixture should be tested according to the specifications, and the test results and frequency should meet the requirements of technical specifications.
(13), joint and U-turn treatment
1. Two working sections constructed on the same day should overlap each other. After paving in the previous section, leave 5 ~ 8m without rolling. In the latter stage of construction, cement should be added to re-mix, and rolled in the latter stage.
2. Treatment of working joint and U-turn: At the end of compacted cement stabilized soil layer, dig a groove with a full width of about 30cm, and dig it directly to the top surface of the lower bearing layer. The groove is perpendicular to the center line of the road, and the side near the stabilized soil should be cut into a vertical plane, and two square trees with the same thickness and half full width as the compaction degree should be placed near the vertical plane. Backfill other parts of the water tank with the original excavated soil. The next day, after paving and rolling in the adjacent operation section, the square wood will be removed and backfilled with mixture. When looking for peace, the water stability of the joint should be about 5cm higher than that of the completed part to form a smooth joint.
3. Longitudinal joint: As the width of the widest lane in this project is 15m, two pavers are used to spread the whole width to avoid longitudinal joint.
(14), construction organization
My project department will arrange five organizations to participate in the construction: personnel, mechanical equipment, materials, transportation and coordination:
1, personnel organization
Personnel organization is mainly divided into two categories: construction management layer and construction service layer.
(1) Organization of construction management personnel
When establishing the project management team of this project, our company will send a project management team with rich construction experience and having undertaken similar projects to the site to directly participate in the construction and management of this project.
Strengthen management to ensure the consistency of the whole project in the whole construction process, thus creating favorable conditions for comprehensive management, comprehensive coordination and comprehensive control.
(2) Construction service personnel organization
The construction service layer is the actual operator in the construction process and the most direct guarantor of project quality, progress, safety and civilized construction. The principles of selecting service-level operators in our company are: having good quality and safety awareness; Have a high technical level; Have similar engineering construction experience.
The service layer is divided into two categories: the first category is highly specialized technical jobs, which are held by experienced personnel who have participated in similar projects in our company. The second category is ordinary technical jobs, mainly organized by construction personnel who have undertaken similar projects. The third category is unskilled jobs, which are construction laborers who have cooperated with our company for a long time. The personnel entering the site have certain construction experience.
(3) Personnel arrangement at the service level
The company has trained some non-migrant workers for a long time, all of whom are skilled workers. Using these personnel can not only ensure the deployment of personnel, but also ensure the quality of the project.
2. Construction machinery.
According to the characteristics of this project, it is planned to adopt 2 sets 18 ~ 2 1t static pressure, 3 sets of 22 ~ 25 static pressure, 3 vibratory rollers, 20 dump trucks, 2 pavers, 2 6000L sprinklers, 4 bulldozers T 140 and140. Each machine is equipped with 1 ~ 2 mechanical operators.
3, material organization
The project department is equipped with full-time material management personnel, who are responsible for the procurement and supply of materials for this project. In the selection of raw materials, all raw materials used in the project need to have formal factory certificates, and the physical and mechanical properties and components of the materials are strictly controlled, especially the raw materials such as coarse and fine aggregates that affect the quality of the engineering structure, which not only need certificates, but also will be sampled and retested according to the corresponding standards to ensure that the quality of all materials used in the project meets national and industry standards.
4. Transport organization
Before the materials enter the site, make a detailed transportation itinerary, transportation time and transportation route plan to avoid poor transportation caused by random stopping and misplacing.
5, coordination organization
During the construction period, high requirements are put forward for the management of the project construction site. Therefore, our company will put the coordination and organization work in an important position, focusing on the coordinated management of construction quality, safety and construction progress of each type of work, providing reasonable construction surface for each type of work, coordinating the connection of each process, and ensuring the water and electricity requirements of each type of work.
At the same time, we should also do a good job in coordinating with the surrounding communities and government departments on the construction site, and equip managers with certain civil engineering coordination ability to form a project coordination team, so as to keep close contact with the surrounding communities in the construction, communicate in time, and solve various frictions and contradictions. Strengthen the management of the construction site, make the construction site a community, and aim at * * * to create a civilized construction site. At the same time, we will fully consider the impact of construction on the surrounding communities during the construction process, and formulate relevant measures to minimize the disturbance to the people and ensure the smooth progress of the construction.
(15), other precautions and safety measures
1. When mixing, the mixing time should be extended as far as possible to ensure full mixing, and there can be no gaps.
2. Before construction, the detailed construction technology should be determined through the test section to guide the construction.
3. When the site temperature is lower than 5℃, no construction shall be carried out, which shall be completed one month before heavy freezing. As the construction period is in winter, the construction progress should be accelerated. After the mixture is rolled, it should be covered with plastic film, felt and other items to keep warm. Pay special attention to the weather change to avoid rain on the mixture. When it rains, the construction should be stopped, but the paved mixture should be compacted as soon as possible.
4. In the construction of cement stabilized macadam, the flow method is adopted, and each process is closely connected to shorten the delay time from mixing to rolling.
5, we send full-time security officer to manage construction machinery, protect dangerous areas, and send full-time electrical equipment operators to manage construction electricity.
Mei Dan Road Bid A Mechanical Schedule
Mechanical name of the month 1 1
1February
Month 1
The second month
March 3
moon
Static pressure is 3y18-21111.
Static pressure ly18-21111.
Static pressure LCS- 18-22b3300
Vibration pressure yz18jb1110.
Vibration pressure sr20m11110.
Vibration pressure LSS21a1110.
Paver 22200
Bulldozer 14044330
Dump truck 2020000
Trolley 10 10 1000
0 0 0 0 0
Construction personnel organization of Mei Dan Road Bid A
Chief Engineer: Xu Shenggui
Project Executive Director: Song and He Bin.
Project Manager: Xia Quanxian
Deputy Project Manager: Wu Guowen
Technical Director: Zhao Xingdong
Technicians (Measurement): Ge, Gan Benyun, Tang Jifeng, Li Wei, Yang Guibin.
Builders: Wu Guowen, Wang, Liu Hui, Yao, Xu Sheng, Cai.
Information Officer: Wang Xiuli Chen Yaling.
Experimenters: Wang Xinzhi, Lu Jie and Wang Xindong.
Electrician: Zhao Anhua
Materials: Dai Longzhu, Wu, Shen Changchun
Finance: Liao Jianzhong
An Quan: Wang, Li Yong, Li Shoubin
Mei Dan Road Bid A Material and Labor Schedule
The name of the material is111212.
Stabilized macadam with cement100 m2 614: 10000.0000000000005
moon
Number of workers1112123
130 130 130 100 100
Crossing chart of lime-fly ash macadam construction progress plan in Mei Dan Road Bid A
(with construction conditions)
moon
Process name 1 1 month 1 February1month.
Last/better/previous/last name
Xunzhong
Xunxia
Xunshang
Xunzhong
Xunxia
Xunshang
Xunzhong
Xunxia
Xunshang
Xunzhong
Xunxia
Ten days.
0-700
hydrology
Gravel 700- 1400
1400-2 102
Project frequency and quality standard for quality control of water-stabilized base
Project frequency quality calibration
The slope of every 2000 meters is within the range specified in the specification.
It is observed that the aggregate pressure value is ≤ 35% at any time when it is abnormal.
Every 2000 m cement dosage, at least 6 samples shall not be less than-65438 0% of the design value.
When abnormal moisture content is found, observe whether the moisture content is within the range specified in the specification at any time.
Should always observe the mixing uniformity, no ash, no ash, uniform color, no segregation.
Every operation section or 1000 m should check the compaction degree 1 time or more, 97%.
The compressive strength of each working section or 2000 m 3 or 6 specimens meets the requirements.
Water-stabilized grass-roots quality inspection project
Check the frequency of the specified value or allowable deviation of the project.
Compaction (%) represents the value of 97: 2 per 200 meters of water per lane.
Extreme value 93
Smoothness (mm) 10 3m straightedge shall be measured at two places every 200m × 10 feet.
Longitudinal elevation (mm)+5,-15 level, 4 sections are measured every 200m.
The width (mm) shall not be less than the design value, and four places shall be measured at 200m.
thickness
Extreme value (mm)
Each lane/10 200 200m 1 min
Representative value -20
The transverse slope (%) is 0.5, and 4 sections are measured every 200m.
Strength (MPa) meets the design requirements. Check according to appendix g of JTJ07 1-98 specification.