statement of method
Production of Precast Concrete Elements:
- Material
All materials that are incorporated to this work should be approved prior to commencement of production operations
- Mould Fabrication
- Mould fabrication is based on approved shop drawings issued by design to production department. Before any mould fabrication takes place, the production engineer and the mould fabricator must ensure that size & all shop drawings of approved.
- Materials for the mould are mainly of fiber (OR) Ms sheets.
- Moulds are fabricated in such a manner that
- They are stable and solidly
- Casting deviations to be readily controlled and/or
- Will allow de-moulding without damaging the precast
- Are free from defects that would impair the surface appearance of the precast
- They are accurately built and all measurements are in accordance with the latest revision approved.
- Control
Mould fabrication is monitored from time to time by the line quality. Upon completion of the fabrication works, the mould is subjected to final quality control inspections.
- Reinforcement Cutting, Bending and binding
- Reinforcement cutting, bending and binding takes place at the steel / reinforcement The reinforcements for precast concrete unit are made as finished / assembled units in the steel workshop.
- The reinforcement work is based on the approved fabrication drawings issued by the design department which contains all the information to make the reinforcing
- Steel reinforcement must be clean and free from stains of oil, grease or dirty that may affect the bonding of concrete
- Placing of cast-in items and reinforcement
- Before any reinforcements and cast-in items are placed the mould inside surface will be treated or applied with approved mould release agent as per the manufacturers’ instruction.
- Reinforcement is placed in the mould supported on concrete spacer blocks to give the required concrete cover and prevent it from being contaminated by the mould oil.
- Concrete Casting
- Concrete is placed to the moulds using a skip hoisted by an Fork lifts. Two alternating concrete skip shall be used for continuous batching and casting to avoid un-intended cold joint.
- Concrete is placed to the mould in a manner that it can be readily compacted to form a homogeneous Compaction and consolidation is by means of table and poker vibrators.
- All non-mould surfaces are screened and toweled to the standard specified / shown on the approved shop
- Depending on the program of production, moulds/elements are covered with appropriate Tarpaulin Cover after finishing works (normally 2 to 3 hours after casting).
- Concrete is sampled at random or number required by the project specification (One set of 6 cubes per 40 cubic meter on each day’s ).
- After 7 days of moist curing, any surface imperfections and blemishes to the units such as those outlined will be repaired and finished to the required PPC standard using approved methods.
- Elements are in gray trowel finish.
- Elements are painted with their respective identification number as given in the drawing.
- Each unit is inspected by QC department and only duly approved elements are delivered to their respective sites supported by wooden dunnage at the correct and specified location and fastened by belt.