Manhole covers are produced from UHPC (Ultra-High-Performance Concrete). UHPC is a very high strength type of concrete with excellent physical and mechanical properties. How to produce UHPC manhole valve includes the following steps:
- Design: First, the geometric design and dimensions of the manhole cover are prepared based on the customer’s needs and relevant standards. In this step, details such as dimensions, thickness, pattern on the valve and necessary tools to connect the valve to the structure are determined.
- Preparing the mold: The mold needed to produce the manhole valve is made in the desired dimensions. The mold is usually made of materials such as steel or cast iron and includes parts that include the different parts of the valve in order and based on the design.
- Production of UHPC: Raw materials for the preparation of UHPC include cement, silica fume, silica powder, mineral powder, steel fibers and water. These materials are carefully calculated and combined in a special mixer or mill. Other additives may be added to the mixture to improve mechanical properties and corrosion resistance.
Filling the mold: The UHPC mixture is filled into the mold and compacted using vibration to remove air around the material and also to relieve the material inside the mold. This step is known as the filling and compaction process.
Drying and curing: After filling the mold, the manhole cover is placed in suitable conditions for drying. This process is time-consuming and may take several weeks or even months. At this stage, the compounds in UHPC are compacted and the mechanical strength of concrete increases.
Demolding and Finishing: After complete drying, the manhole valve is removed from the mold. At this stage, the edges of the manhole are shaped using suitable tools and any cleaning, polishing and final finishing is done. This includes surface coating, painting, installation of fittings and locking systems and other final details to make the manhole valve usable and installed in the desired location.
Producing a manhole cover made of UHPC requires a lot of precision and expertise because UHPC has a more complicated production process than ordinary concrete due to its exceptional properties. The advantages of using UHPC include high resistance to impact, corrosion and water, long life, high resistance to pressure and tension, accurate dimensions and high strength of the structure.
Manhole cover production sample of Hamyar Beton Shirkooh Company
