ACCOA is manufacturing AAC 'Blocks' accordingly to ASTM C-1386 (Standard Specification for Precast Autoclaved Aerated Concrete (PAAC) Wall Construction Units) and AAC 'Panels' accordingly to ASTM C-1452 (Standard Specification for Reinforced Autoclaved Aerated Concrete Elements) with the strength class AAC-4/600 (Standard Production).
The dry weight of this type of AAC is 38 pcf (600 kg/m³) and the minimum compressive strength is 580 psi (4 N/mm²). The design weight of the PAAC-4/600 equals 45 pcf or 30 lbs/ft² for the thickness 8.0”. The transport weight of the PAAC-4/600 equals 50 pcf.

Dimensional accuracy and compressive strength allow AAC to be used in many load bearing applications. Installed using thin bed mortar, the resulting wall functions as a monolithic structure.

Available in the AAC 4.0/600 and AAC 4.0/500 classification of compressive strengths,ACCOA blocks can be used in the construction of both loadbearing and non-loadbearing walls, and for single-storey and multi-storey buildings.

Compressive strength

AAC is typically classified according to its compressive strength, which ranges from about 250 psi to 1000 psi. These have corresponding oven-dry unit weights ranging from 25 to 50 pcf. The compressive strength is highly dependent on the density of the material, and it increases with increasing density. The relationship is somewhat linear and may be estimated using empirical equations similar to the following: f'c = 23 W - 280 where f'c is expressed in lb/in2 and W is the oven-dry unit weight in lb/ft3. Such an equation, however, has to be adjusted to account for actual raw materials and production process.

Modulus of rupture

The modulus of rupture is approximately 1/4 the compressive strength and may reach 40% of the compressive strength in some cases. The relatively high value for the modulus of rupture in AAC may be advantageous in block construction where flexural tension stresses may be allowed under transient loads.

Direct Tensile Strength

The direct tensile strength is somewhat less than the flexural tensile strength of the material. It is estimated at about 1/5 of the compressive strength. Very limited test data is available on the direct tensile strength of AAC, and direct tension is typically not allowed in the design of unreinforced construction.

Shear strength

Pure shear strength values may be estimated at 1/4 the compressive strength. These values are particularly needed in the design of shear walls and diaphragms.

Modulus of elasticity

The modulus of elasticity (Young's modulus) is a function of the density and compressive strength. It is affected by the moisture content almost in the same manner as the compressive strength. The modulus of elasticity is dependent on the direction of load application in relation to the direction of the expansion of the material. Both properties are about 9 percent lower on the average when measured in the direction of expansion. Simple relationships for the modulus of elasticity E as a function of density may be obtained from statistical analyses of test data. One such relationship may be given as E = (10.9 r - 75) 103 Where E is in lb/in2 and r is the dry bulk density in lb/ft3 at a moisture content of about 3 percent by mass.

Density

The bulk density of the dry material is in the range of 15-60 pcf. The low density is attributed mainly to the large volume of air bubbles in the mass, which in effect replace the coarse aggregate in normal weight concrete. For a typical grade of PAAC with dry bulk density of 32 pcf, approximately 80 percent of a unit volume is air. It is primarily due to the low density that the material acquires its improved and fascinating properties. Manufacturers typically specify the exact dry density of their product, which may differ depending on the raw materials and the manufacturing process. The actual density of the product is usually higher due to moisture or reinforcement.

ACCOA AAC Product Characteristics