Technical

Method of Statement

Construction of Flat Concrete Floor

1. Introduction

InnerWorks Design+Build is a supplier and applicator of high-tech commercial and industrial super flat floors. We have well experienced and competent management, reliable supervisors and a team of highly skilled & experienced workers. We work hand-in-hand with our principal manufacturers to ensure that we constantly provide the best quality products and produce remarkable performance at a cost effective price, tailored to individual needs. Our customer are our most valuable asset. Thus, we strive to yield the best return to our customers’ investment in terms of quality, time and cost.

2.Sub-base slab

The sub-base for the concrete floor must be constructed according to the specification. The sub-base must be well compacted and well prepared in order to avoid settlement in the future.

3.Concrete Strength

The characteristics strength of the concrete shall comply generally with SI or ASTM standards. Ready mix should be of consistent properties and its reply should be stable in order to achieve high level of floor flatness.

• Concrete Grade : Min 30 MPa Concrete
• Slump : 11 ± 1 cm (arrival on site) & consistent in quality
• Initial setting time : 3 to 5 hours

4. Quality control

The main Contractor, the concrete supplier and floor specialist shall implement quality control testing throughout the supply of the concrete to the project so as to fulfill the performance requirements of the specifications

• The design mix is to be pre-determined.
• The sand silt content should not be more than 1 %.
• Air entraining agent is not recommended if floor hardener is to be used.

5. Pour Schedules

Determine the sequence and timing of each pour with consideration of the following : –
• Determine area to be poured and finished in each work period.
• Formwork should be made of rigid steel with top level same as floor finishing level.
• Ensure concrete will be delivered in uniform and continuous supply for each concrete pouring.
• The interval for each truck is to be on time to ensure a continuous flow of concrete.
• Slump test is to be done for every truck.
• Concrete laying shall be in one direction following the floor level.

6. Environmental Control

The concrete placing and finishing for the floor hardener shall be protected against direct sun light, rain and strong wind. Roof and side wall cladding’s must be installed before the construction of the slab.

 

7. Sequence of Work

7.1. Set up laser Screed

The main contractor shall provide suitable bench marks for setting up of laser base stations.
The main contractor shall also provide lifting services to unload equipment and shift the equipment to the floor for the setting up of the equipment. Setting up of laser screed shall be done by the subcontractor.

7.2. Initial concrete placement

All concrete to be discharged into the pouring area shall follow good concrete placing method.

7.3. Vibrating concrete

During concrete discharge, wet concrete shall be vibrated with a poker vibrator especially at edges or beam area. The vibrator shall be inserted vertically into the concrete.

7.4. Floor finishing consists of five major steps

A. Striking-off
B. Flatness Enhancement
C. Application of floor hardener (where applicable)
D. Floating (Ride-on trowel and power trowel)
E. Troweling to Dense Smooth Finish
A. Striking-off
Also known as screeding by laser Screed is the process of leveling the fresh concrete. It takes place immediately after the placing and compacting operations. It is important to have good accuracy in striking to achieve floors flatness and levelness.
B. Flatness enhancement.
The flatness of the floor is further enhances by flat floor tools and equipment. These equipment includes channel float, checker rod and bump cutter.

7.5. Measurement for floor Flatness (FŦ) “Dipstick” F – Number System

The measurements (FF) are to be done using the “Dipstick” digital floor measurement instrument capable of reading to 0.1mm accuracy in accordance to ASTM E1155 and ACI 302 Standard.

7.6. Time of measurement (FF)

Measurement of floor flatness should be made, within 72 hours especially on the first mock up sample.

7.7. Handover

The completed floor shall be considered handover to main contractor after inspection and measurement of floor finish. The floor shall be protected by main contractor.

8. Protection Against Damage

The concrete shall be protected from damage due to load over stress, heavy shock and excessive vibration, surrounding the concrete area particularly during curing period. Construction load shall not be placed on newly completed floor. Traffic should be kept off the finished floor for 3 days or longer to avoid surface damages and scratch marking. All finish concrete surface shall be protected from damage by construction equipment, materials or other heavy tools.