Roofing WORKSTATION Micro Concrete Roofing Tiles

Manufacturer
Domtec Company Limited
1005/29 Soi Prachachuen 30
Bangsue, Bangkok 10800, Thailand

Tel: (66-2) 910-1463
Fax. (66-2) 910-1465

Description:

A complete workstations for producing Micro Concrete Roofing (MCR) tiles consists of a vibrating table, an electric motor, 200 plastic moulds and interface sheets, an admixture container and testing equipment for quality control.

Figure

The vibrating table consists of a screeding table and a steel chassis. An electric motor is bolted to the machine in order to vibrate the mixture for compaction.

A container is used to keep fresh concrete mixture to produce tiles. It is made of a steel box (60 cm x 65 cm x 20 cm) fixed on a steel chassis. The box has a sloped front in order to take out the mixture easily.

Moulds are of two types: the moulds for regular tiles are made of ABS plastic and are rectangular in shape with broken wedges. The profile of the tiles is corrugated. The moulds for the ridge tiles are made of wood and steel and have a V-shaped profile.

Figure

Interface sheets are used to transfer fresh mixture from the vibrating table to the moulds. They are placed on the vibrating table under the screeding frame before the mixture is scooped onto it.

The testing equipment used for Bending and Nib Tensile tests consists of a steel frame with two angular sections fixed at a distance of 400 mm.

Figure

MICRO CONCRETE

The Micro Concrete Roofing technology is a relatively new technology that can be used to produce inexpensive and reliable concrete tiles for roof cover. The tiles are light, durable and can be made using locally available raw materials: cement, sand and stone-dust.

Figure

RAW MATERIALS:

Cement: Portland cement needs to be used in the production of MCR tiles. The cement should be of the standard required for normal concretework. The amount of the cement required for a tile of 8 mm. thickness is 0.45 kg.

Sand: The sand should be well graded, clean and free of organic materials. The clay and silt content of the sand should not exceed 4%. Sand should be seived with a mesh size of 2 mm.

Stone-dust: It should have the same characteristics and properties as sand. The maximum size of the aggregate should not exceed two-thirds of the tile thickness. They should be as clean and free from clay as the sand.

Water: The water should be clean and fresh, and free of salt. If the water quality is doubtful, it can be tested in laboratory for salt content and other chemical contamination.

Colourant: The MCR tiles are naturally light grey in colour. To achieve a more attractive product they may be coloured by using additives to the admixture such as iron oxides or carbon black (darker grey tiles) or, they can be painted using a spray gun or brushes.

Placement: Metal wire is used for fixing the tiles to the roof structure. Galvanized steel wire of 2 mm. diameter should be used for this purpose as it will not corrode. These wires are placed in the nibs when the tiles are fabricated.

PRODUCTION PROCESS:

The general steps are the following:

- Mortar Preparation
- Vibrating and moulding
- 24 hrs mould curing
- Demoulding
- Curing / storage
- Quality control

Figure

ROOF STRUCTURE:

In order to construct a reliable roof, not only the roofing material must be of good quality, but also the entire roof must function as a coherent system adapted to local conditions such as the climate, the available skills and structural materials. Roof structures are affected by the following factors:

Load: Conventional concrete and clay tiles weigh 50 to 80 kg per square meter whereas MCR tiles on the roof structure varies from 20 to 37.5 kg per sq.m. depending on thickness. Consideration should be given to live loads such as wind and rain depending on local conditions.

Slope: The minimum slope required for the MCR tile roofs is 22° in areas with moderate climate and 30 to 40° in areas with severe driving rains.

Battens: The spacing of the battens for MCR tiles is 40 cm. The battens can be of wood or steel sections.

Structure: The section and spacing of the purlins and rafters arc calculated according to the type of materials, slope, climatic conditions, and weight of the tiles.

TRAINING:

Training in production of MCR tiles and in managing production units can be provided by Habitech Center at its typical production facilities on AIT campus. Follow-ups and testing for quality control of the production are provided as an integral part of the training.

The training cost is established on a case by case basis. For information and details, please contact:

Habitech Center

Asian Institute of Technology
G.P.O. Box 2754, Bangkok 10501
Tel: (66-2)524-5611
Fax: (66-2) 516-2128

APPRO-TECHNO S.A.