Concrete Building Bricks & Hollow (FT Type) Slab Blocks

The Hollow Concrete Block

The function of the hollow blocks is purely a void former to accept the space of initial ready mix, which would have been poured over the total slab area if the slab were a solid slab. The hollow blocks have no structural value. The strength of the slab material is in the pre-cast rib that consists of the girder with the reinforced steel as subscribed by the engineer. The engineer might also suggest beams at some openings for strength. Stiffener / Cross rib steel is the other part of the slab that determines the strength.

The hollow concrete block is manufactured in a range of sizes to provide the designer with full flexibility in determining an appropriate slab dept and rib arrangement to suite one’s particular needs. Blocks are manufactured under strict control procedures from concrete with a 28-day cube strength which ensures that when tested in a compression testing machine they have a minimum crushing strength of 7MPa measured on the net section when axially loaded in direction of compressive stress in the finished slab.

REF CODE	DEPT mm	WIDTH mm	LENGTH mm	APPROX. MASS PER BLOCK (KG)
FT110	110	500	200	20
FT140	140	500	200	21
FT200	200	500	200	26
FT250	250	500	200	31

Please Note: Hollow Blocks – FT-110 – FT-140 – FT-200 – FT-250

Hollow blocks are used to determine the correct lattice beam rib spacing.

During the installation process, it is recommended that no walking on hollow blocks but to use scaffolding planks for traffic over blocks.

For best results, it is best to water down the complete system before pouring of ready mix.

Our hollow blocks are tested for MPa (megapascal), which measures compressive strength of the concrete mix. Our block strength as set out in our design manual needs to be 7mpa by 28 days.

We test our blocks every 4 months, although we have used the same mix for the past 15 years.

04 Day Test Result = 10.0 mpa
10 Day Test Result = 11.5 mpa
17 Day Test Result = 16,5 mpa

Polystyrene Blocks

Polystyrene is 90% lighter than concrete blocks, therefore reducing 1.6KN/m² of dead load. This is approximately 140kg per m² on a 255mm slab. Compared to an in-situ, the weight saving is even greater, being 320kg per m². The lower weight advantage allows engineers to use polystyrene slabs on buildings where the foundation history is unknown.

The Polystyrene Block Range:

REF CODE	DEPT mm	WIDTH mm	LENGTH mm	APPROX. MASS PER BLOCK (KG)
PB110	110	500	200	0,000296
PB120	120	500	200	0,000323
PB140	140	500	200	0,000376
PB200	200	500	200	0,000269
PB250	250	500	200	0,000336

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Please Note: We operate within a 300km radius from our premises in Lewzene Estate, Old R513 Road, Cullinan, Gauteng, South Africa.

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info@pjprojects.co.za
customer@pjprojects.co.za
Phone: 012 736 9056
Mobile: 072 049 9560