aluminium formwork construction Common quality problems and countermeasures

Aluminium formwork is a prevalent and extensively utilized formwork material in the construction industry. It is crafted from high-strength aluminium alloy, possessing advantages such as lightweight, exceptional durability, and effortless installation and dismantling. As a result, it has gained widespread application in the field of construction. Aluminium formwork construction finds primary application in various building structures, including floor slabs, walls, and beams. Whether it is residential buildings or commercial constructions, aluminium formwork is capable of fulfilling diverse construction requirements. Its flexibility and adjustability enable it to adapt to different design specifications and complex structural configurations. Despite the numerous advantages of aluminium formwork construction, there are still construction issues that arise during its practical usage. Through this article, we will primarily address these issues and propose corresponding strategies to enhance the quality and effectiveness of aluminium formwork construction.

● Advantages of aluminium formwork

Aluminium formwork possesses numerous advantages and significance in construction, which have led to its widespread adoption. These characteristics include:

1. Lightweight: Aluminium formwork is relatively light in weight, facilitating easy handling and installation, reducing labor intensity, and improving construction efficiency.

2. Strong Durability: Aluminium formwork has high strength and durability, capable of bearing significant loads and pressures. It is less prone to deformation or damage during long-term use, effectively extending the lifespan of the formwork.

3. Convenient Installation and Dismantling: Aluminium formwork design utilizes modular design, making installation and dismantling simple and convenient. It eliminates the need for extensive wood processing and assembly, saving time and labor costs.

4. Smooth Surface Finish: The surface of aluminium formwork is finely treated to ensure the quality of concrete pouring during construction and to make the appearance of the building more beautiful.

● Questions about aluminium formwork construction

1、Question: The strength of aluminium formwork profile may not meet the requirements and they are prone to deformation during the construction process.

Solve: Prior to installation, it is imperative to conduct a strength acceptance test on the aluminium formwork profile to ensure its compliance with prescribed standards. It is recommended to employ aluminium materials from the 5-series or 6-series due to their heightened strength and durability. In addition, acceptance tests should be conducted on weld seams, joint widths, pins and wedges. Weld seams need to undergo a thorough inspection of welding processes and quality to ensure strong and reliable joints. Joint widths should conform to design requirements to avoid construction difficulties or quality issues caused by excessive or insufficient widths. The quality and dimensions of pins and wedges should also be verified to ensure the effective connection of components of aluminium formwork.

2、 Question: The aluminium formwork system might suffer from inadequate overall rigidity due to the large number of small panels used in construction.

Solve: The aluminium formwork system(aluminium formwork system) is assembled with aluminium alloy plates to form a complete framework, featuring a high bearing capacity reaching 30-40kn per square meter. However, the use of a large number of small plates may result in inadequate overall rigidity, leading to structural deformation. Therefore, during the aluminium formwork design calculation, non-standard formworks design should be attention such as beam-column and beam-wall joints as well as the formwork design for the lower edges of wall corners to optimize the overall structural rigidity and reduce the risk of deformation.

3.Question: The concrete surface detachment after the formwork for aluminium was dismantled
Solve: Before using formwork for aluminium, it is essential to apply form release agents every time. This practice effectively prevents adhesion between concrete and formwork for aluminium, ensuring a smooth concrete surface during dismantling. We recommend choosing a water-based form release agent as it is environmentally friendly and easy to clean. When applying the form release agent, it should be brushed from top to bottom. This method ensures thorough penetration of the release agent and minimizes waste and ineffectiveness during application.

4、 Question: During aluminium formwork in construction, leakage at the joints will result in honeycombing on the surface of the concrete, which seriously affects the appearance of the structure.

Solve: In aluminium formwork in construction, if the cement residue is not properly cleaned or if the joints are not tightly sealed, it may lead to leakage. Therefore, immediate cleaning is necessary after the removal of aluminium formwork panels. The purpose of cleaning aluminium formwork panels is to ensure optimal construction results and prevent the occurrence of grout leakage issues during future use. The cleaning process involves the thorough removal of residual cement and other contaminants from the edges, as well as addressing any joint-related concerns. Furthermore, any deformed or damaged used aluminium formwork should be promptly sent back to the manufacturer for repairs, in order to prolong its service life and reduce subsequent maintenance costs.

5、 Question: the columns, walls, and stairs were displacement.
Solve: If the displacement is within the allowed range (≤5mm for columns and ≤3mm for walls), no further treatment is needed. If the displacement exceeds the allowed range (5mm ≤ column ≤25mm and 3 mm ≤ wall ≤15mm), To address this issue, it is possible to install kicker in aluminium formwork, which should be affixed to the structure. When dismantling the lower wall panels, it is crucial to refrain from removing kicker in aluminium formwork.

6、 Question: There were cracks and leaks at the junction of the aluminium formwork system and decks.

Solve: aluminium wall formwork can be removed after 12 hours, the slab formwork can be removed after 24 hours, and aluminium formwork beams should be removed after 36 hours.

However, it is important to note that the timing of dismantling is also influenced by other factors such as temperature and should be adjusted accordingly based on specific circumstances. At lower temperatures, the dismantling time may need to be extended, while at higher temperatures, it may be possible to shorten it. It is crucial to always retain aluminium formwork props during the dismantling process to prevent cracking at the connections of the aluminium formwork system. Their function is to provide additional support and stability, ensuring that the structure can still bear loads after the aluminium formwork system is removed. Therefore, aluminium formwork props should be retained for a certain period, typically around 21 days, after the removal of the aluminium formwork system, to allow the concrete to attain sufficient strength and prevent cracking or deformation.

7. Question: There were leaks at the bottom of the aluminium wall formwork, resulting in damage to the bottom of the wall.
Solve: After the completion aluminium wall formwork of concrete pouring , we suggested using a laser level to level the area within 20cm around the bottom of the wall and column for facilitating the fixation of the rocker. Fill all gaps before pouring.

8. Question: There are air bubbles and swelling phenomena appearing on the bay window.
Solve: During the process of pouring concrete, the bay window area is under significant pressure and may experience swelling. To reinforce this area, flat tie, steel waler, and shoring props should be taken on the bay window. It is also recommended to punch hole in the bay window panel to reduce the occurrence of bubbles.

9、 Question: In aluminium formwork construction, the occurrence of air bubbles on the concrete surface

Solve: Water reducing agent is added to prevent air bubbles before concrete pouring. During the aluminium formwork construction, the concrete needs to be poured in layers, and the thickness of each layer should not exceed 1.25 times the length of the vibrating rod. Vibration can be stopped when the concrete surface is level and no bubbling occurs. In addition, during the construction process, it is recommended to use wooden sticks to tap the outside of the aluminium formwork from bottom to top to help the concrete fill completely.

10. Question: The misalignment of the beams has caused poor wall flatness.
Solve: The reason for this is due to the eccentric load acting on the beam, causing beam displacement. Prior to concrete pouring, the beam should be strengthened by using temporary supports to stabilize it and adding additional steel reinforcement while also increasing its cross-sectional area.

Aluminium formwork construction may encounter some of the aforementioned quality issues, which can result in decreased construction quality, increased safety hazards, and shortened aluminium formwork system lifespan. Therefore, it is crucial to implement corresponding measures. By introducing ten common issues with aluminium formwork construction in this article, users can gain a better understanding of aluminium shuttering (formwork) technology, ensuring construction quality, safety, and efficiency. Additionally, regular maintenance and upkeep can extend its service life and reduce operating costs. Customers are welcome to contact us via WhatsApp to explore more construction solutions.