Road reconstruction project of XXXXXXXX project
Engineering quality evaluation and evaluation report
Compile:
Chief supervision engineer:
Technical director:
XXXX Construction Project Management Co., Ltd. (Seal)
September 28(th), 2009
catalogue
Foreword ............................................... ..
I. Basic information of the project. ..
(1) Project overview.
(2) Basic information of the contractor
(3) Quality evaluation basis
(4) Main construction methods.
(5) Engineering supervision.
(6) Quality of subgrade engineering and pavement engineering ........................
(7) The quality status of ancillary works.
(8) Quality accidents and problems in construction, cause analysis and treatment results. ........
Second, the comprehensive evaluation opinions on the project quality ............................................
order
XXXX Construction Project Management Co., Ltd. is entrusted by XXXX Group Co., Ltd. to supervise the road reconstruction project of XXXX project. The project supervision department began to supervise the project in the construction stage on September 23, 2008. With the joint efforts of the construction unit, design unit, construction unit and supervision unit, the road reconstruction project and storage and transportation reconstruction project of the development line reached the basic completion conditions on September 28, 2009.
I. Basic information of the project
All parties involved in this project:
Construction unit: XX Group Co., Ltd.
Design unit: XX Engineering Design Co., Ltd.
Employer: XXX Construction Group Co., Ltd.
Supervision unit: XXX Construction Project Management Co., Ltd.
(1) Project Overview
1, project features:
1) unit project name: road reconstruction project of XXX project.
2) Project location: 1# Road: a sentry-Erdaogang entrance.
Road 2#: the entrance of the general material warehouse-the entrance of the second finished product warehouse.
3# Road: entrance (south gate) of the second finished product warehouse-entrance of troops in the factory.
3) Pavement type: cement concrete pavement, with total thickness of pavement structure layer of 70cm(68cm).
4) Total road length:1331+1507.805+962.8+476.8 = 4278.405.
5) Planned commencement date: September 23rd, 2008.
6) Planned completion date: June 2, 2009
7) Engineering quality grade: qualified
2. Geological conditions: some sections are sandstone, and the rest are four types of soil.
3. Architectural features: The original design of this project consists of three parts. During the construction, Party A adds a raw material transportation road in the production area, in which 1 road and the raw material transportation road in the production area and 1. 13km in front of No.2 road are all 7m wide, with a concrete surface layer of 25cm, and the remaining sections of No.3 road and No.2 road are all 3.5m wide, with a concrete surface layer of 22cm, and the thickness of other structural layers. Due to the limited design depth of drawings, the elevation and curve of some sections can be adjusted according to the site topography during construction. See the corresponding atlas number for the pavement practices of each fork and intersection.
4. Structural features: the pavement structure layer * * * is composed of four parts, namely, after the original subgrade is rolled and accepted, the natural macadam cushion with 15cm is made on it, with a degree of compaction of 95%, the lime-fly ash macadam subbase 15cm, with a degree of compaction of 95%, and the cement stabilized macadam subbase 15cm, with a degree of compaction of 98%.
(II) Basic information of the contractor
Contractor: XXXX Construction Group Co., Ltd. Municipal Bridge Engineering Company
Contract contents: all contents in the construction drawings.
Labor subcontracting team: the labor team of municipal bridge engineering company of XXXX Construction Group Co., Ltd.
The contractor's on-site project executive manager is fully responsible for the construction task of road reconstruction project of XXXXX project, and all management personnel are fully equipped and qualified. The post certificates of construction personnel and professionals are complete and meet the requirements. The quantity of labor meets the requirements of the construction period. The specifications, models and quantities of various construction equipment meet the construction requirements. Engineering raw materials, components and equipment can be implemented according to the use plan. According to the investigation of the construction unit and the main engineering raw materials and components, it is determined that the construction unit and the supply unit have the ability to complete the construction project of this project.
(3) Evaluation basis
1, construction specifications, procedures and engineering acceptance criteria
1) Code for Construction and Acceptance of Asphalt Pavement (GBJ92-86)
2) Standard for Quality Inspection and Evaluation of Municipal Road Engineering (CJJ 1-90)
3) Code for Construction and Acceptance of Urban Road Subgrade Engineering (CJJ44-9 1)
4) Code for Construction and Acceptance of Water Supply and Drainage Pipeline Engineering (GB 50268-97)
5) Technical Code for Construction of Highway Bridges and Culverts (JTJ04 1-2000)
2. Engineering survey and design documents 1) Geological survey data 2) Standard atlas of construction drawing, design description and design designation 3) Minutes of design disclosure meeting and design change documents 4) Engineering change documents proposed by the construction unit 3 Contract 1) Construction project supervision contract signed by the construction unit and the supervision unit 2) Construction project construction contract signed by the construction unit and the construction unit.
(4) Main construction methods adopted
As this project is the only passage for Yin Guang factory to transport dangerous goods, semi-open construction method is adopted, that is, some sections are still used for normal traffic. Considering the flow construction mode, the construction party, the supervisor and Party A divided the project according to the requirements of the driving route in the factory, and defined the construction time, closing time and driving route of each section in the construction plan, ensuring that the production in the factory would not be affected under normal construction conditions. After determining the construction time of each section, the construction party will strictly follow the plan. When the subgrade is excavated, it shall be leveled initially with a mechanical excavator loader, then leveled manually, and finally rolled by a roller. The natural gravel subbase is distributed according to the working face, and the loader is leveled at the beginning, leveled manually, and rolled by the roller. Lime-fly ash macadam subbase and cement stabilized macadam subbase are mixed in the factory, and the aggregate is loaded in the yard by loader. Manual microcomputer control electronic scale to measure mixing ratio. Fly ash and cement are both fillers, and the mixture is stirred by mixer and transported by motor vehicle, which ensures the mixture ratio and mixing of lime-fly ash macadam and water-stabilized macadam. The construction method of cement concrete pavement is mainly three-roll paver, supplemented by vibrator, electric trowel and artificial wood trowel, and the construction quality has achieved good results. Other auxiliary projects are interspersed according to the progress of the main project.
(5) Engineering supervision
1, pay special attention to prior control and strictly control the construction.
In the whole supervision process, the supervision department insists on pre-control and active control, formulates supervision plans according to contracts and design documents, formulates specific supervision work procedures, and defines work contents, actors, acceptance criteria and work requirements. Before the commencement of this project, according to the requirements of the supervision specification, the supervision department reviewed the qualification of the construction unit, on-site quality management and technical management institutions, personnel, systems, qualifications of operators of special types of work and employment certificates. According to the application form of construction organization design scheme submitted by the contractor, the construction organization design is reviewed, and the supervision objectives and requirements are further defined, which creates conditions for the smooth development of supervision work.
2, strictly control the raw materials and semi-finished products come into play.
All incoming raw materials and semi-finished products must be inspected in writing first, that is, the certificate of approval and test report. , meet the requirements for appearance inspection. After there is no abnormality, the samples witnessed by the supervisor will be sent to Lanzhou Jianke Testing Center for re-inspection, and the materials after re-inspection can be used in the site, and the unqualified materials are refused to be used in the project. The certificate and re-inspection report of building materials in this project are complete, including 5 certificates and re-inspection reports of steel products, 0/2 certificates and re-inspection reports of cement products, 8 re-inspection reports of fine aggregates, 8 re-inspection reports of coarse aggregates and 2 re-inspection reports of fly ash and lime, all of which meet the qualified requirements.
3, strict process inspection, strengthen process control.
In the process of construction supervision, strengthen the means of construction process inspection, so as to carry out inspection before construction, and the construction of the next procedure shall not be carried out without acceptance of the previous procedure. My project supervision department pays special attention to the acceptance of concealed works, and on-site supervisors supervise key and key parts, such as subgrade frost boiling treatment and surface concrete pouring. In the process of construction, we attach great importance to and strictly control the construction quality of concrete pavement. In the whole construction process, we focus on controlling the expansion joint, the location of expansion joint, the placement of expansion joint reinforcement, the treatment of base course, the stability of formwork, the thickness of panel, the mixture ratio of concrete and the maintenance of poured concrete to ensure the construction quality of concrete.
(six) the quality of subgrade engineering and pavement engineering
1, subgrade engineering quality status
As this project is the reconstruction and expansion project of the old road in the plant area, the subgrade quality of some sections has been boiling after years of use. Considering that this road is the main dangerous goods transportation channel in Yin Guang plant area, our supervisor has put forward higher quality requirements for subgrade engineering construction. Whenever the soil conditions of each excavation section are different, the constructor's testers are required to take samples on site for compaction test to ensure the accuracy of compaction. Plaster must be thoroughly dug out in the mud-turning section, and then the side station shall be supervised to tamp with natural gravel layer by layer. 1 When the road section is about K 1+300~K 1+400, the elevation has reached the requirements according to the drawings. However, considering the clear height at the bottom of the bridge and the bearing capacity of passing vehicles, the supervision department put forward the requirements for the second side reduction for the construction party, and the construction party actively cooperated. In the subgrade construction of the whole project, in order to ensure the normal traffic of raw materials and product vehicles in the factory, through the coordination and communication between Party A and the construction party, the scheme of subsection construction was formulated, and the driving range of transport vehicles in the factory in different construction sections was delineated. Party A of Yin Guang Factory actively cooperated and supported this, so that the subgrade construction can be carried out normally and orderly. The supervision of subgrade construction process adopts patrol and sampling inspection, and the road sections are accepted one by one according to the specification requirements. The quality is under control. If the deviation value of the measured project during acceptance is greater than the specification requirements, the contractor shall be informed orally or in writing to make rectification, and the rectification situation shall be further tracked to meet the requirement that unqualified projects shall not enter the next working procedure. After the completion of subgrade construction, a total of 10 batches were inspected, of which the inspection times of inspection items were as follows:
Compaction: 93 points pass rate 100%.
Smoothness: 2 18, and the qualified rate is 9 1. 17%.
Elevation of longitudinal section: 220 points, and the qualified rate is 86.25438+0%.
Transverse slope: 294 points, and the qualified rate is 90.96%.
Judging from the quality control and measured data, it reflects that the quality of subgrade has reached the qualified standard.
2. Present situation of pavement engineering quality
1) Quality of natural gravel cushion
After the acceptance of the road bed, the building materials used for the cushion are natural gravel. Before construction, the compaction test has been completed by sampling the material source, and the number of cloth steps is preliminarily calculated according to the daily workload and the virtual paving thickness of gravel, then cloth is distributed at night, paved by loader during the day, and then leveled manually by machine for the second time. After leveling, the road section will be rolled by a two-wheel roller. After initial rolling, the water content will be detected by the builder. When it is close to the optimal water content, the roller will be rolled from low to high and from side to middle, and the wheel tracks will be repeated every time 1/2~ 1/3. After the completion of rolling, the supervisor and the tester of the construction party will use sand filling method to test the compactness on site. If the measured degree of compaction fails to meet the design requirements, the roller will be rolled again until it meets the requirements. In the process of construction, the construction personnel will simultaneously test its flatness and width, virtual paving thickness, etc. And all the measured items are basically the same. At the same time, the supervisors of all measurement items are randomly selected to ensure that all measurement items are within the controlled range and will not cause large-scale rework. In order to ensure the assembly line construction, the construction party and the supervision party cooperate closely and adopt the method of subsection construction and subsection acceptance. After the acceptance, the road section shall be sprinkled with water in time, and vehicles are prohibited from passing, thus ensuring the quality of the cushion. The whole road section is divided into 9 inspection lots, of which the measured values of inspection items are as follows:
Compaction: 82-point pass rate 100%
Fluency: 2 17, with a passing rate of 88.75%.
Width: 124 points, qualified rate 100%.
Elevation of longitudinal section: 222 points, with a qualified rate of 88.0%.
Transverse slope: 298 points, and the qualified rate is 90.2%.
Thickness: 36-point qualified rate 100%
Judging from the quality control process and the measured project data value, the quality of cushion reaches the qualified standard.
2) Lime-flyash macadam subbase
According to the drawing, the ratio of lime-fly ash to crushed stone in lime-fly ash macadam subbase is 5: 15: 80. In order to ensure the accuracy of measurement in construction, our supervisor strictly requires that the electronic scale batching, mixer mixing, paving method, leveling and rolling process are the same as the cushion construction process. In order to ensure the mixture ratio and compaction density, the supervisor will randomly check the electronic measurement data and the water content of the mixture at any time, and consider the dry humidity of the material source. The water injection amount shall be appropriately adjusted according to the measured water content. Judging from the rolling effect, the water content is basically controlled at the best water content value, so the rolling compactness has all met the design requirements. Before the construction, strict quality and technical disclosure was made to the workers. During the construction, the nesting, flatness and cross slope of aggregates basically did not deviate from the specification requirements. Through the strict control of subbase construction technology, the measured project values are within the allowable deviation range, thus controlling the quality of lime-fly ash macadam subbase and realizing the whole road section.
Compaction: 42-point pass rate is 100%.
Fluency: 2 17, passing rate 90. 5%.
Width: 1 10 minute, passing rate 100%.
Elevation of longitudinal section: the passing rate at 223 points is 9 1.97%.
Transverse slope: the passing rate of 295 points is 9 1.87%.
Thickness: 28-point qualified rate 100%
Judging from the quality control process and measured engineering data, the quality of lime-fly ash macadam subbase reaches the qualified standard.
3) The quality of cement stabilized macadam base
The dosage of cement in cement stabilized macadam base is 5%, and its grade is 32.5 Wang Xian cement. Like lime-fly ash macadam base, electronic scale batching mixer is used for mixing. In order to ensure the accuracy of dosage, the field tester randomly selects cement dosage for titration test every day, and the supervisor conducts inspection and spot check every day, and even monitors the whole process of paving and rolling the mixture. When it is found that the cement dosage is less than 4.5%, the construction party is required to increase the cement proportion of the mixture that has arrived at the site according to the difference, and conduct secondary mixing at the site. After strict supervision and control, the cement content of the mixture has fully met the requirements of the specification, and the mixing, paving and rolling of the mixture are also carried out according to the requirements of the specification, and its quality is basically within the control range. After the completion of rolling, the measured items such as compaction degree shall be detected in time, and the plastic film shall be sprayed for curing after passing the test, and the curing period shall be more than 7d. The concrete surface construction of some sections of 1 road was not completed before wintering. Therefore, in order to ensure that the water-stabilized base does not freeze, overwintering protection measures are taken, with plastic film on the surface and gravel with a thickness of 15~30cm above the film. After the second year of construction, the section was inspected, and the results showed that the wintering measures achieved the expected effect and the foundation was not damaged by freezing. Judging from the whole construction process, measured data and appearance inspection, the quality of the base reaches the qualified standard, and the whole section is divided into
Compaction: the pass rate at 36 points is 100%.
Smoothness: 2 18, and the qualified rate is 9 1. 55%.
Width: 1 10 minute, passing rate 100%.
Elevation of longitudinal section: 2 18 points, with a qualified rate of 90. 19%.
Transverse slope: the passing rate of 274 points is 9 1.6%.
Thickness: 33-point qualified rate 100%
Judging from the quality control process and measured engineering data, the quality of water-stabilized macadam base reaches the qualified standard.
4) Surface quality of cement concrete
Cement concrete pavement is paved with three-roll paver, assisted by manpower. Paving is carried out in two pieces, each with a width of 3.5m and a total width of 7m. Before concrete construction, the raw materials entering the site shall be strictly sampled to ensure the hardness and geometric size of the gravel, the silt content in the sand washing and the stability and stability of the cement. Before the official opening of the market, the contractor has been required to carry out C30 concrete trial mixing, and the concrete trial mixing is normal before the formal pouring. Throughout the process, the supervisors at the concrete pouring site stood by. Before concrete pouring, the supervisor checked the stability of formwork support, the height difference between adjacent formwork, the thickness of panel, the cleaning of base and the wetting of water. According to the specification requirements, concrete shall be poured after reaching the qualified standard. During the pouring process, when the cloth is about 5- 10 m, the vibrator starts to vibrate evenly along the "S"-shaped route, and then the paver begins to level and lift the slurry. Paver operation ensures that the slurry on the concrete surface is the original concrete slurry, and there is no self-made cement paste block phenomenon during plastering, which ensures that the pavement will not peel after normal traffic. The drawings require a false contraction joint to be set every 6m, so the construction party is required to leave construction joints at contraction joints or expansion joints as far as possible to ensure the natural cracks of the pavement slab are neat, and the joint cutting time is basically controlled within 24h according to the specification requirements, thus effectively preventing temperature difference cracks. After plastering, use film to maintain and cover the straw curtain in time.
However, in the second year of concrete construction, it was in June and July, and the direct sunlight temperature was not considered in the construction process. At the same time, in order to speed up the concrete construction progress, normal concrete construction will be arranged from 12: 00 to 3: 00 pm, so that the completed road section will exceed 100 m every day, the retained road section of construction joints will be too long, and the sprinkler maintenance period covered with grass curtains will not strictly reach 7 days, resulting in pavement cracks due to temperature strain. The director and the director worked together to solve the problem. B pay attention to sewing time; C, due to temperature factors, concrete pouring is not allowed from noon 12: 00 to 3: 00 pm; D, shortening the indwelling length of construction joints; E, strengthen grass curtain coverage and water conservation; Ensure that the concrete is wet within 7d. In the later concrete pouring process, concrete cracks shall be effectively controlled in strict accordance with the above requirements. For the cracks that have appeared, the method of planting steel bars and pouring concrete after cutting is adopted in No.3 Road, and the effect is good. For other parts that can't be cut, professional crack treatment glue is used to treat them, and the effect meets the expected requirements. Measure the overall quality of concrete surface, check the appearance quality and reach the qualified standard.
Elevation of longitudinal section: 22 1 point, and the qualified rate is 88.98%.
Smoothness: 2 16, and the qualified rate is 9 1.5%.
Width: 109, qualified rate 100%.
Transverse slope: the passing rate of 275 points is 9 1.79%.
Height difference between adjacent floors: 2 15, and the qualified rate is 94.04%.
Longitudinal seam straightness: the pass rate at 45 points is 85. 1%.
Transverse joint straightness: 109, and the qualified rate is 84.55438+0%.
Honeycomb pockmarked area: 197 points, and the qualified rate was 89.63%.
Thickness: 3 1, qualified rate 100%.
In the whole construction process, * * * kept 70 groups of standard curing test blocks, basically one group per day, and the strength at 28d age all reached the design strength value.
Judging from the quality control process and the measured project data value, the quality of cement concrete pavement reaches the qualified standard.
(7) quality of ancillary works
The ancillary works are mainly composed of drainage ditch and circular pipe culvert. The construction supervisor of this part of the project carried out inspection and sampling control, and the quality was controlled. Rubble used in mortar drainage ditch is hard, and mortar is dense and seamless during masonry. The measured data show that the quality reaches the qualified standard. Buried PVC double-wall corrugated pipe drainage ditch has no scratches on the pipeline, smooth inner wall, tight connection of sockets during construction and no water leakage. The bottom is covered with yellow sand. Backfilling the side wall and pipe top with yellow sand effectively protects the pipe wall. After pipeline laying, recheck the slope of the drainage pipe, and the minimum slope is 0.8%, which meets the requirement of minimum drainage slope of 0.3%. By checking its quality, six inspection lots were made for the whole drainage ditch. In fact, the measured data are as follows:
Trench section size: 3 points qualified rate: 100%
Elevation of trench bottom: 8: 00, and the qualified rate is 80%.
Verticality of wall: 5 points, qualified rate: 90%
Wall flatness: 5 points, qualified rate: 90%
Verticality of sideline: 5 points, qualified rate: 80%
Two groups of mortar test blocks were retained, all of which reached the qualified standard.
The K 1+704 pipe culvert is the original 1-4m slab culvert updated to φ 1500 pipe culvert. Its construction technology is simple. The original slab culvert wall and trench bottom are paved, and only the pipe culvert foundation is backfilled and poured within the elevation range. After the pipe joint is installed, check the joint of the pipe joint and seal it tightly. For the area above the pipe top exceeding 1m, make the surface structure layer. Laying 40cm double-layer bidirectional steel mesh along the middle line of the pipe culvert within the range of 10m on both sides of the road, and pouring C30 concrete to protect the bearing capacity of the pipe culvert. The measured quality of pipe culvert reaches the qualified standard. The data are as follows:
Axis deviation: 90% at 2 o'clock.
Adjacent pipes are staggered: 80% at 5 o'clock.
Insole elevation: 90% at 2 o'clock.
Culvert length: 1 point 100%
(eight) release the quality accidents, problems, causes and treatment results in the construction.
In the whole construction process, quality accidents are concrete surface cracks, some are semi-penetrating cracks, some are short cracks around 1 m, but they are all transverse cracks without crisscrossing.
1, cause analysis:
The main factors causing cracks are: a) the direct sunlight temperature in the construction section at noon is too high; B concrete construction joint lien section is too long; C. The curing period of straw curtain covering and sprinkling water is not strictly up to 7d; D. The personal insertion time exceeds the specified insertion time; E, high silt content in single sand washing;
2. Treatment method:
According to the situation of pavement cracks, the construction party consulted the experts of Beijing Academy of Sciences, who recommended a material with the trade name of Covetin. The construction party bought this product from Beijing according to the recommendation of the experts, and the manufacturer sent professionals to conduct professional training for the construction party personnel before leaving. The person in charge of the construction party made a special treatment plan for concrete pavement according to the training points, and then treated the pavement cracks. The main construction techniques are as follows:
Crack treatment → Bury the glue injection nozzle with repair glue → Seal the joint → Check the seal → Prepare the glue injection → Inject the glue → End → Check.
The key points of construction are as follows: firstly, clean the cracks with a brush to remove dust and oil stains. If the cracks are wet, bake them with a gasoline blowtorch; After the crack is cleaned, the grouting nozzle shall be fixed at the crack according to the crack width, and the maximum spacing shall not be greater than 40cm. Then the two components of MS-402 sealant were prepared into sealant according to the ratio of MS-402 (material A): MS-402 (material B) = 2: 1, and the cracks were sealed, and the sealant was cured for about 3 hours. According to MS-40 1 (material A): MS-40 1 (material B) = 4: 1, two components of structural adhesive A and B for caulking reinforcement were prepared. Sealants should now be used to prevent gelation. The sealant should be used up at 25℃ within 50 minutes after preparation to obtain the prepared MS. The glue will be pushed into the gap with the extension of the spring until it is full. The maximum capacity of the glue injector for one inhalation is 50 ml. After treating a crack, take the glue dispenser and immediately cover the plug, and treat all cracks in turn according to this method.
3. Processing results:
After all cracks are treated, the sealing condition of cracks is detected by water injection method after 3 days. The results show that, except the raw material transportation road in the production area, other roads have basically achieved the sealing effect, and the cracks in the raw material transportation road in the production area need to be further treated.
Second, the comprehensive evaluation opinions on the project quality
The quality grade agreed in the construction contract of this project is: qualified. The contractor's quality target positioning: qualified. Arrange the input with qualified targets. The supervision unit evaluates the acceptance of subdivisional works, divisional (sub-divisional) works and unit (sub-unit) works, and thinks that the works have reached the engineering quality requirements agreed in the construction contract, and at the same time, the data has been sorted out, complete, true and effective, and the unit works have passed the pre-acceptance.