Leca® HD - Low Weight / High Strength Aggregate LWAC
Technical Specifications
• The product complies with: EN 13055-1
• Fraction: 4-12 mm
• Loose bulk density: 610-700 kg/m 3 (approx. 320 kg/m 3 on average)
• Crush resistance: 5 N/ mm2
• Thermal conductivity: λ = approx. 0.100 W/mK*
• Reaction to fire: class A1 (non-flammable)
*For dry aggregate
Leca® HD - Low Weight / High Strength Aggregate
Structural applications where normal weight concrete is not the preferred solution and a Higher Strength Leca® Lightweight Aggregate Concrete (LWAC) is the solution, Leca® HD is the aggregate of choice.
Leca® Lightweight Aggregate Concrete Applications
By using a lower density concrete longer span can be achieved. Thus, the positioning of the foundation are more flexible and large costs are saved.
The use of LWAC will create a slimmer and more cost-effective construction with lower amount of total use of concrete and therefore, also a greener construction.
The use LWAC in the deck structure of cable-stayed bridges either as a fully LWAC structure or in composite solutions of LWAC/NDC/steel structure.
In general, reduced construction costs are achieved due to lower need of concrete volume which can be proven during the design phase
• Floating Structures
The use of LWAC is in floating structures like Wind Turbines, barges, floating fish farms, floating bridge foundations etc.
The LWAC can be made with considerably lower density and keep much of the mechanical characteristics from NDC. LWAC service densities in the range of 1600-1950 kg/m3 will result in characteristic compressive strength of 35-65 MPa and achieve considerably better structure buoyancy.
High pumping power should be avoided for LWAC, since it can promote segregation, changing also the absorption and the consistency of the placed concrete
In general, LWAC can be easily pumped when pre-saturation is assured, until the internal moisture is circa 15%, assuming also that the viscosity is not too high. However, the pump selection depends a lot on the desired pumping performance and on the transport capacity (in height and in distance), being able to use, stationary pumps with compressor or; auto-pumps, with pressure technology applied by piston pump.
Batching of lightweight concretes is normally done from ready-mixed concrete producers.
At low work abilities, the concrete can easily be placed by skip or chute. Pumping lightweight concrete can be achieved, but care needs to be taken so that the concrete mix doesn’t separate. For pumpable mixes it is usual to use a natural sand, i.e. not to have a lightweight aggregate for the fine portion of the mix and to have a high workability so that increased pump friction and blockage is avoided. This is achieved with the use of admixtures. Over vibration of a lightweight concrete tends to cause segregation so a flowing concrete is best used when it is to be pumped as it requires only minimum vibration.
Compressive strength classes according to EN 1992.
Concrete Solution
What are structural lightweight concretes?
Density classes according to EN 1992. Note 1:The density classes are based on oven dry concrete. Note 2: Fresh density is typically 150 kg/m3 higher than dry density.
Leca® HD LWAC applications
Long Span Structures / Structural Concrete
How and where to utilize the LWAC?
Table 2. Compressive strength classes according to EN 1992.
Areas of Coverage
Lightweight concrete is covered in Eurocode 2 Part 1-1, with section 11 having rules required for lightweight aggregate concretes.
