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Pavement reconstruction project of trunk highway in xx city

The fourth paragraph is the same.

(K329+000-K332+000)

Masonry small low wall

Sub-project commencement report

The fourth contract project department of xx trunk highway pavement reconstruction project

June 8(th), 2007

Pavement reconstruction project of Datong trunk highway

Construction Organization Design of K329+000-K332+000 Masonry Small Low Wall

I. Overview of the Project:

The K329+000-K332+000 pavement reconstruction project of Datong trunk highway undertaken by our project department is 3000m long, 0.5m wide and 45cm high. The structural form is: 7cmc 15 concrete +38cm7.5# mortar rubble, and cement concrete is provided with 1 expansion joints every 5m. * * * 7.5 # mortar rubble 380m3, cement concrete 70m3.

Second, the construction schedule:

The construction of this project began on June 9, 2007. According to the capacity of mixing equipment, and considering the influence of adverse factors such as weather, the planned construction period of this section is 6 days, and it is scheduled to be completed on June 14, 2007.

Three, the main mechanical equipment of this subdivisional work:

Serial number mechanical name model quantity

1 forced mixer 4

2 vibrator 15

3 tire loader ZLM50B 1

4 Generator set 30Kw 1

5 Dumping trucks 8

6 Sprinkler 6

Four, the main construction personnel of this subdivisional work:

Person in charge: xx

Technical director: xxx

Worker: xx

Tester: xx

Surveyor: xx

Safety officer: xx

Verb (abbreviation of verb) construction scheme

(1) material

1) cement

Cement should be rotary kiln road portland cement, rotary kiln portland cement or ordinary portland cement; The cement pavement of this bid section belongs to heavy traffic grade. The flexural strength and compressive strength of cement at all ages, the chemical composition and physical and mechanical indexes of each batch when cement enters the site shall be attached, which shall conform to the current national standards, and the qualified documents such as the cement quality inspection report of the manufacturer shall be attached. After cement enters the site, it shall be accepted in batches according to its variety, strength, supporting documents and delivery time. The cement used should be rechecked and tested. Bagged cement should be moisture-proof during transportation and storage, and the stacking height should not exceed 10 bag. Cement with different strength grades, varieties and factory dates should be stacked separately. Cement shall be re-sampled for inspection if it is damp or stored for more than 3 months, and shall be used according to the re-inspection results.

2) Coarse aggregate

Coarse aggregate should use hard pebbles or crushed stones, and should be inspected in batches according to different conditions such as origin, category, processing method and specifications, and stacked separately, and shall not be mixed. Its grade should not be lower than Grade II, and the water absorption of Grade I aggregate should not be greater than1%; The water absorption of secondary aggregate should not be greater than 2%. Coarse aggregate should be mixed with grade 2-4 aggregate according to the maximum nominal particle size, and its crushed stone technical index and coarse aggregate grading range can be implemented according to the current Test Code for Aggregates in Highway Engineering (JTJ058).

3) Fine aggregate

The fine aggregate shall be hard, durable and clean natural sand, machine-made sand or mixed sand, and the sand used shall be no less than Grade II. River sand should be used for heavy traffic concrete pavement, and the silicon content of sand should not be less than 25%. Sand for pavement should be medium sand, and sand with fineness modulus of 2.0-3.5 can also be used. The variation range of fineness modulus of sand with the same mixture ratio should not exceed 0.3, otherwise it should be stacked separately and used after adjusting the sand ratio in the mixture ratio. In addition, the polishing value of mortar should also be tested and should be greater than 35. Mudstone, shale and slate with poor wear resistance should not be used to produce machine-made sand. The test of fine aggregate can be carried out according to the current Code for Aggregate Test in Highway Engineering (JTJ058).

4) Sheet shape

Generally, it refers to the stone mined by blasting or wedge splitting, and the thickness should not be less than 150mm (oval and flake shape are not allowed). The sheet used as veneer should be selected with relatively flat surface and large size, and should be slightly trimmed. Stone should be tough, firm and durable, with appropriate and meticulous texture, even color and no scale stone on the hillside.

5) water

Drinking water can be directly used for concrete mixing and curing. In case of doubt about water quality, the following indicators should be tested, and only those who pass the test can use them.

(1), and the sulfate content (calculated as SO42-) is less than 0.0027mg/mm3.

(2) The salt content shall not exceed 0.005 mg/m3.

(3) The 3)PH value shall not be lower than 4.

(4) Do not contain oil, mud and other harmful impurities.

6) Mortar

The types and strength grades of mortar should meet the design requirements. The mixture ratio of mortar can be determined by experiments, and the mass ratio or volume ratio can be adopted, and it should meet the requirements of technical conditions in this specification. When the composition materials of mortar change, the mixture ratio test should be carried out again. Mortar is stirred mechanically, evenly and in the same color. Mortar must have good workability, and its consistency is expressed by standard cone penetration. Stone masonry should be 50 ~ 70 mm, and it can be increased appropriately when the temperature is high. The consistency of mortar used in sporadic projects can also be checked by intuitive methods. The mortar will be kneaded into small balls by hand, and it will not be loose after letting go, nor will it be shed by the ash shovel.

(2) Construction method

1. construction preparation: prepare enough gravel, sand and cement needed for construction, and the raw materials must meet the requirements of the specification.

2. Engineering lofting: According to the drawing data, pile driving and lime line shall be spread every 20m.

3. Masonry: The block must be watered and wetted before use, and the surface should be cleaned if there is dirt or scale. When laying the first floor block, if the basement is a rock or concrete foundation, the basement surface should be cleaned and wetted first, and then mortar should be laid; If the basement is soil, it can be laid directly with mortar.

Masonry should be built in layers. When the masonry is long, it can be built by sections and layers. In layered masonry, it is advisable to form a working layer with 2 ~ 3 layers of blocks, and the horizontal joints of each working layer should be roughly leveled. For each layer, the outer ring positioning row should be built first, and then the inner layer should be built, and the outer ring block should be staggered with the inner layer block into a whole. Masonry exposed surface facing type should comply with the design regulations, outer ring positioning column and corner stone, flaky with square shape and larger size should be selected, and they should be occluded with the inner block at intervals. The vertical joints of each working layer should be staggered and not penetrated.

Each build by laying bricks or stones a layer of blocks should be placed firmly, and the mortar between blocks should be full and firmly bonded, and it is not allowed to be directly attached or hollowed out. When laying, the bottom slurry should be covered, and the vertical seam mortar should be laid on the side of the built stone first, and then the stone should be packed and compacted after being put away.

When laying the upper block, the vibration of the lower block should be avoided. When masonry is resumed after the interruption of masonry works, the surface of masonry layer should be cleaned and wetted.

4. Maintenance: After initial setting of mortar, mortar masonry should be watered for 7 ~ 14 days. Collision, vibration or bearing should be avoided during curing.

5. Cement concrete mixing: Before the short retaining wall starts construction, the equipment can be installed, tested and debugged only after the commencement report is submitted to the supervision engineer for approval, so that the mixed cement concrete can meet the specified requirements. Cement concrete is mixed by special mixing equipment, and continuous forced mixing is adopted. Before each mixing equipment is put into production, calibration and trial mixing must be carried out. After the calibration expires or the mixing equipment is moved and installed, it should be recalibrated. During the construction period, check the metering accuracy of the mixing equipment every 15d. When mixing equipment with computer automatic control system is used, automatic batching production should be adopted, and daily concrete batching statistical data and deviation should be printed as required. In the process of concrete mixing, sand and gravel materials with drainage, snow cover and dust on the surface shall not be used.

When mixing concrete ingredients, all kinds of scales should be kept accurate. The moisture content of aggregate should be tested frequently, and the number of tests should be increased in rainy days to adjust the dosage of aggregate and non-aggregate. The concrete mixture should be evenly mixed, with the same color, without segregation and bleeding. The inspection method for the uniformity of concrete mixture shall be carried out according to the current national standard Technical Conditions for Concrete Mixers (GB9 142).

(3) Transportation

When transporting, the vehicle type and total number should be selected according to the construction progress, traffic volume, transportation distance and road conditions. The total conveying capacity should be slightly greater than the total mixing capacity. Ensure that fresh mortar and concrete are delivered to the paving site within the specified time. The mixture transported to the site must have workability suitable for paving.

In addition to the above provisions, the transportation of the mixture shall meet the following technical requirements:

(1), before loading, clean the tank, sprinkle water to wet the wall and drain the accumulated water. When loading, the dump truck should move the parking space to prevent segregation. The discharging gap of mixing equipment should not be greater than 2m.

(2) During transportation, slurry leakage, material leakage and road surface pollution should be prevented without delay. Dump truck transportation should reduce bumps and prevent mixture segregation. The vehicle should start and stop smoothly.

(3), once stay in the car for more than the initial setting time, emergency measures should be taken to deal with, it is forbidden to harden the mixture in the car (tank).

(4) Dump trucks should be covered during long-distance transportation in hot sun, strong wind, rainy days and low temperature days.

(5) The longest transport radius of dump truck for transporting mixture should not exceed 20km.

(6) When the transport vehicle turns around or makes a mistake in the template or traverse area, it is forbidden to collide with the template or baseline. Once it collides, the surveyor shall be notified to make measurement and rectification.

(7) When reversing and discharging, there should be special personnel to command. Unloading should be in place, and it is forbidden for paver to collide with frontcourt construction equipment and measuring instruments. After unloading, the vehicle should leave quickly.

(4), pouring

Before pouring concrete, the supports, templates, steel bars and embedded parts should be inspected and recorded, and concrete can be poured only after meeting the design requirements. Debris, water and dirt on the steel bars in the formwork should be cleaned up. Template if there is a gap, should be tightly packed, template inside besmear brushs release agent.

Installed formwork shall not be crushed, crushed or deformed by concrete or machinery. There should be a special person to direct the vehicles to discharge evenly.

When the distribution length of concrete mixture is greater than 10m, the vibrating operation can be started. When vibrating, it shall meet the following requirements:

1) When using the plug-in vibrator, the moving distance should not exceed 1.5 times of the action radius of the vibrator; Keep a distance of 50 ~ 100 mm from the side formwork; After each vibration, the vibrator should be slowly raised while vibrating; Avoid vibrating rods colliding with templates and other embedded parts.

2) For each vibrating part, it must be vibrated until the concrete in this part is dense. The sign of compactness is that the concrete stops sinking, there are no more bubbles, and the surface is smooth as slurry.

(5), concrete curing

1) Maintenance shall be started immediately after concrete pouring is completed. In rainy days or when there is enough water for health care, methods such as covering moisturizing film, geotextile, sacks, straw bags and straw curtains can be used. And it is not appropriate to use the method of confining water for health care. The initial curing time of covering plastic film is based on not crushing the meso-anti-sliding structure. The thickness (toughness) of the film should be appropriate, and the width should be greater than 600mm of the coverage. When the two films are butted, the lap width should not be less than 400 mm, and the films should always be completely covered during the curing process.

2) Covering health:

(1), it is advisable to use moisturizing film, geotextile, sacks, straw bags, straw curtains and other coverings for health preservation and sprinkle water in time to keep the concrete surface moist all the time, and thus determine the number of times of sprinkling water every day.

(2) Concrete constructed in areas where the temperature difference between day and night is greater than 10℃ or the average daily temperature is less than or equal to 5℃ shall be kept warm and moist.

(3), curing time should be based on the concrete compressive strength growth. Should not be less than 80% of the design strength, should pay special attention to the first 7 days of moisturizing (warm) hygiene. Generally, the days of health preservation should be 14 ~ 2 1d, the days of high temperature should not be less than 14d, the days of low temperature should not be less than 2 1d, and the days of low temperature should be appropriately extended.

(4) At the initial stage of concrete curing, people, livestock and vehicles are forbidden to pass, and pedestrians can only pass after reaching 40% of the design strength.

Six, intermediate completion

After the completion of the low retaining wall project, the data are completely sorted out and submitted to the supervision engineer for intermediate completion after inspection.

Seven, quality time limit for a project guarantee measures

Quality assurance measures

1, strengthen quality awareness, conscientiously implement the policy of "quality first", organize construction in strict accordance with design drawings, current specifications, planning, special technical requirements of the owner and on-site instructions of the supervision engineer, implement the goal of creating excellence in the whole process of construction and production, and ensure project quality.

2, improve the total quality management and quality assurance system at all levels. Set up a total quality management leading group headed by the project manager. Do a good job in engineering quality management.

3, strengthen project management, implement the technical responsibility system, formulate targeted special construction scheme, and make technical disclosure seriously.

4. Do a good job in engineering survey, test and re-inspection, strictly implement the system of double inspection and re-inspection of measurement, and ensure that all technical indicators meet technical requirements.

(2) time limit for a project guarantee measures

1, invest enough management strength, technical strength and labor force, quickly enter the construction site, establish various management systems, and ensure that the project starts on time.

2, choose the best construction scheme, reasonable arrangement, scientific and orderly, point line surface clear, light and heavy, to ensure that key projects and general projects, and timely adjust the allocation of resources according to the progress of the project, to achieve optimal resources.

3, advanced equipment, improve work efficiency, ensure quality, ensure the completion as planned, and provide material guarantee. According to the characteristics of this project, we will equip construction machinery with advanced performance and high efficiency, strengthen the maintenance of machinery during construction, ensure the intact rate and utilization rate of construction machinery, and realize mechanized operation.

4. Seize the opportunity, set off a construction climax, carry out socialist labor competition activities in a timely manner during the construction, carry forward the spirit of "being good at fighting and striving for first-class", and speed up the construction progress.