Hebel Research Part 3 (Material Properties)

The Material Properties of Hebel

Hebel Products may contain up to 30% residual moisture (by weight) as supplied. This will increase the product weight to the figures shown in Table. 04 as Working Density.

Average reinforcement weights have been included in the panel and lintel working densities. Some of the panel products may have higher reinforcement contents and consequently higher weight. The properties f’m and f’mt are applicable to constructed walls. These values can only be applied to Hebel walls constructed with Hebel Thin Bed Adhesive. To adopt Hebel f’mt values, Hebel recommends testing in accordance with AS3700-1998 Clause 3.3.3 and Appendix D.

Table 05. Material Properties of Hebel AAC Products

1) Frost Resistance
The cellular nature of Hebel, incorporating millions of pockets of trapped air, gives the product remarkable protection against frost. Tests have shown than Hebel products have greater resistance to frost compared with traditional masonry products such as clay bricks. As a matter of principle however, building materials should be protected against excessive wetting in severe winter climates.

2) Workability
Hebel blocks can be sawn, drilled, nailed and routed using normal wood working tools. This greatly increases onsite productivity as applicable services can be routed in after the structure has been erected. Note, the recommendations of the Building Code of Australia should be followed with regards to routing/chasing and services. The fact that Hebel blocks can be easily cut means curves and mites can be used to add to the creativity which the designer can express on any project.

3) Moisture resistance
Hebel is superior to normal concrete in water permeability because of its cellular structure and discontinuous microstructure. Tests conducted at CSR Building Materials Research Laboratory to British Standard 4315 Part 2 1970 “Methods of Test for Resistance to Air and Water Penetration” demonstrate the superior moisture resistance of walls constructed out of Hebel blocks compared with traditional masonry products. The test results are shown in Chart 2.1. Note, the results of the testing clearly indicate that the Hebel AAC products (such as block walls) are not waterproof, yet exhibit a slower water penetration to the other masonry types assessed.

4) Drying Shrinkage
Expected moisture content varies between 30% (by weight) ex-factory and an installed equilibrium value of approximately 5% to 10%. For this range, the value of drying shrinkage is in the order of 0.2mm/m. Depending on site conditions this decrease can take up to 1 year to occur.

5) Other Physical Properties
Thermal Expansion: The thermal expansion co-efficient of Hebel is 10 x 10^-6/˚C which is lower than that of normal concrete. Movement over a 24 hour period is negligible due to the

insulation properties.

Air Permeability: The air conductance coefficient of Hebel Thermoblok is 31 x 10^-6m3/m.h.Pa. The coefficient for panels is 18 x 10^-6 m³/m.h.Pa.

Melting Point: Hebel, like most cement materials, melts at approximately 1600˚C.

Chemical Properties: Hebel is alkaline (pH9.0-10.5) and will not corrode other building materials. Like other cement- based products, Hebel should be protected against high concentrations of carbon dioxide, sulphates, chlorides and strong acids.

Toxicity: Hebel does not contain any toxic substances and emits no odour.

Vermin Resistance: Hebel will not harbour or encourage vermin. Hebel recommend detailing in accordance with BCA or relevant standards to discourage/prevent the ingress of vermin.

Hardness: Hebel has been tested by the CSIRO and the AAC product was assessed as being satisfactory in terms of AS2185 and is not less hard than plaster.