Expressways have very high quality requirements, ensuring continuous and safe traffic. Therefore, when implementing construction, it is necessary to pay attention to a number of technical and quality issues unique to expressway projects.
To achieve technical and quality requirements in expressway design, construction and operation, typical issues related to expressway technique and quality must be updated and clarified. to avoid or promptly overcome problems related to the quality of the project.
TECHNICAL REQUIREMENTS FOR QUALITY MANAGEMENT OF HIGHWAY CONSTRUCTION
Compared to normal motorways, expressways have different characteristics, typically: large volume, construction over a large area, so it is difficult to ensure uniform quality horizontally and vertically; Large volume leads to long construction time. Therefore, some parts and items are easily affected by natural damage, reducing quality right during the construction process and as soon as work is completed but before the next items can be implemented. The criteria and requirements for design and construction quality (geometric dimensions, flatness, compaction density, material quality...) are all highly required to ensure the long life of the road. Highway. Expressways have great socio-economic significance and very high investment capital, so if damage occurs early, it will have a negative impact on public opinion and highway operations.
The Trung Luong - My Thuan expressway project has BEN Construction Company as a subcontractor
STRICTLY MANAGE ALL STAGES DURING THE CONSTRUCTION PROCESS
For the pre-construction phase, actual implementation has shown that there are still some errors in design documents, including construction drawings. Many provisions stipulated in the "Technical Regulations" of expressway projects are generic copies, lack detail, specificity and are not even suitable for on-site conditions or specific technical characteristics of the project. each project. On the other hand, the contractor's field laboratory and testing consultant are deployed slowly compared to the general construction progress and lack capacity; There is no temporary road to serve construction, construction subcontractors are not qualified; Do not carry out test construction work...
Therefore, at the construction preparation stage, it is necessary to closely review and fully implement contents such as: Additional surveys to prepare detailed design drawings; Review the project's "Technical Regulations"; field laboratory testing; Check temporary roads (service roads) along the route; Check the type, quality and quantity of vehicles, machines (construction equipment) for each project item to be constructed; Implement trial construction work before mass construction; Check the capacity of subcontractors (in case the main contractor hires subcontractors).
During the construction process, the following problems are frequently encountered, which have a great impact on the quality of the project: Materials used do not meet standards of quality, origin and uniformity; lack of seriousness in controlling the quality of completed construction parts (items) before moving on to the next construction part (item); The inspection is still passive (according to the contractor's request letter), not proactive; There is no assessment of the uniformity of the quality of the project; The system of forms from daily inspection and acceptance work to forms for construction completion documents is still long and complicated, causing obstacles for contractors and consultants.
Therefore, quality management contents during the construction process need to be focused, including: Material quality management, source (type) of materials used for each work item or part of the project. ; quality control of completed construction parts (items); Applying "dynamic" quality management methods during construction; Regularly review, supplement and complete inspection and acceptance forms, including forms serving construction completion reports.
The Trung Luong - My Thuan expressway project has BEN Construction Company as a subcontractor
NOTE WHEN CONSTRUCTING EXPRESSWAYS
Road base construction is currently considered simple by contractors (just "earth work"), forgetting that this is one of the particularly important stages, determining the long-term sustainability of the overall structure. road surface base.
For embankments, common problems encountered when constructing this item are: No temporary drainage measures and surface protection during construction; failure to comply with regulations on thickness and horizontal slope of spread layers; not paying attention to controlling the best moisture content of the material; The number and type of rollers are not enough, and there is often a lack of leveling rollers before completing each layer. In some cases, to be pumped from the barge into the construction site, the sand often has a very high moisture content (to the point of liquefaction) and is pumped with a large thickness, very negatively affecting the quality of the roadbed. To overcome it, it is necessary to resolutely control the thickness, drainage ability, humidity and compaction of the embankment layers according to regulations.
Particularly for embankments on soft soil, we have now almost mastered the design and construction of embankments on soft soil. However, during the exploitation process, damage still appears in this area, the main cause of which comes from the unsecured loading and consolidation time. Therefore, planning to carry out construction early or on schedule in these areas is extremely important.
Regarding the construction of crushed stone foundation layers, this construction phase still has a number of problems: The aggregate material is not tested and moistened to the best level before being spread onto the roadbed for compaction. ; spread and roll into tracks only 3.5 - 4.0m wide (creating too many vertical contact streaks across the entire width of the highway surface); The surface of the construction layer does not have a horizontal slope or is uneven (after watering it sticks, when it rains, the water stagnates into small holes and puddles right on the surface of the layer); not paying attention to operations to prevent stratification of grain sizes when spreading; lack of light rollers to roll the first rounds (preliminary rolling); lack of maintenance to limit the effects of rain and traffic on the foundation surface after the foundation is completed while waiting for the upper layer to be applied.
For the construction of asphalt concrete layers, it is necessary to manage the quality of asphalt mixture production according to the "dynamic" method mentioned above, which focuses on the change of components of each batch and temperature. and mixing time per batch. Marshall samples must be taken and cast for each mix to serve as a basis for determining the standard density corresponding to each asphalt concrete spreading process in the field (for checking the compaction density of asphalt concrete for each spraying section at the scene). During the construction of asphalt concrete, it is necessary to comply with the requirements and instructions in TCVN 8819:2011, in which it is necessary to pay attention to: Must have all types of rollers (there are 3 types), control temperature at all stages, control The roller travel and number of rollers are exactly as confirmed during trial construction. In particular, for open terrain areas, high winds, and high humidity (especially riverside and seaside areas), it is necessary to take measures to minimize the influence of surrounding environmental conditions on the temperature of the area. asphalt concrete. When necessary, the length of the construction line can be shortened and the number of construction machines can be increased to reduce the asphalt concrete compaction time for each line.
To ensure the quality of the project, some technical requirements as well as common problems related to the quality of highways are often considered simple and "already known" but they occur very often. be seriously considered and implemented so that the expressway project can fully exploit its functional capacity in a sustainable and long-term manner.
Source: Compiled
Construction of highways or transportation infrastructure projects is always the strength of BEN Construction Company . Road construction capacity has been highly appreciated by investors for its quality, as well as ensuring it meets schedule and is absolutely safe. Participating in the construction of many large projects across the country
BEN Construction Company is constantly improving and developing, always maintaining its commitment to sustainable quality with partners and gradually asserting its reputation in the market.
