Technical · 4 min
Lightweight Infill Block for Precast Frames
Published:
Short answer: Precast concrete buildings utilize lightweight concrete blocks for infill walls to avoid adding excessive non-structural dead loads onto structural beams and foundation connections. TÜRKBETON manufactures Redblok lightweight concrete block within the KB500 to KB800 design density range (500 to 800 kg/m³ dry density). Compared to standard concrete at approximately 2,400 kg/m³, this reduction significantly lightens the structural system.
Precast building wall material selection and frame compatibility
Selecting the right precast building wall material requires careful alignment between skeletal drift flexibility and non-structural dead weight. General masonry structural rules are outlined under TS EN 1996-1-1. Partition panels placed between columns must not transfer unexpected lateral stiffness to primary beams during seismic events. Normal weight concrete typically ranges between 2,300 and 2,500 kg/m³, which imposes substantial gravity and shear stresses on precast corbels and grade beams.
Flexible ties are installed at column-wall interfaces to accommodate joint movement. Redblok lightweight concrete blocks are cured and dimensionally cut within factory conditions, facilitating clean masonry execution. TÜRKBETON does not manufacture autoclaved aerated concrete; its product is non-autoclaved lightweight concrete block. Reducing dead load allows engineers to configure sleeker structural columns across wide spans.
Lightweight block density classes and performance
The choice of density class depends primarily on whether the infill functions as an interior partition or an external perimeter envelope. For interior partitions requiring lowest dead load, class KB500 delivers a dry density of 500 ± 50 kg/m³, a target 28-day compressive strength of 1.5 to 2.5 MPa, and thermal conductivity between 0.12 and 0.14 W/mK. These figures serve as design targets verified through standard laboratory tests.
For exterior infills where wind suction resistance and anchor holding capacity are critical, higher classes such as KB700 or KB800 are indicated. Class KB800 features a dry density of 800 ± 50 kg/m³ and compressive strength between 4.0 and 6.0 MPa. Because typical insulation materials such as mineral wool or EPS exhibit conductivities around 0.03 to 0.04 W/mK, masonry blocks alone rarely satisfy extreme thermal requirements; supplementary continuous insulation must be determined according to local energy conservation codes.
Comparative dead load calculation example
Consider a standard precast warehouse bay with a 6.0-meter span and a 4.0-meter clear height, representing an infill panel area of 24 square meters. Assuming a standard wall thickness of 0.20 meters, the total gross volume equals 4.8 cubic meters. Filling this opening with traditional dense concrete at 2,400 kg/m³ introduces an overall wall mass of approximately 11,520 kg onto the supporting foundation tie-beam.
Utilizing Redblok lightweight concrete block in the KB600 class at an engineered dry density of 600 kg/m³ yields a total wall mass of approximately 2,880 kg. This dead load savings of 8,640 kg per bay substantially reduces foundation moments and seismic base shear across the structure. Blocks are cured in the manufacturing plant, meaning no wet site curing is required during installation.
Selection criteria and decision framework
Engineers specifying partitions for industrial frames evaluate specific boundary constraints. Decision case one: Non-loadbearing interior division requiring minimum frame weight. Action: Specify KB500 block with 500 kg/m³ density to keep dead loads minimal. Decision case two: Internal utility corridors requiring bracket pull-out capacity. Action: Specify KB600 block providing 2.2 to 3.5 MPa compressive strength range.
Decision case three: Outer perimeter walls subject to lateral wind loading. Action: Specify KB700 or KB800 blocks paired with flexible movement ties. To limit moisture ingress, exterior envelopes must be protected with vapor-permeable water-repellent render. When precast skeletal systems are coordinated through BETTON PREFABRİK industrial facility solutions, infill joint details should always be verified by the structural engineer of record.
Frequently asked questions
- What block type is used for infill walls in precast buildings?
- Non-autoclaved lightweight concrete blocks with dry densities between 500 and 800 kg/m³ are preferred for precast frames. Redblok lightweight concrete blocks significantly lower non-structural dead weight on columns, beams, and foundations while providing reliable dimensional accuracy across modular bays.
- What is the recommended precast building wall material for infill panels?
- Engineered lightweight concrete block is the primary recommendation for precast building wall material. It provides substantial dead load reduction compared to heavy masonry, ensuring structural frame stability and enabling rapid assembly without applying unexpected rotational stiffness to skeletal connections.
- Do lightweight blocks require site curing during construction?
- No, site curing is neither necessary nor recommended during construction. Redblok lightweight blocks undergo an initial 24-hour moisture retention barrier and controlled factory curing prior to precise block cutting. Construction workers on site strictly handle thin-joint adhesive application and perimeter anchorage placement.
Sources and standards
- TS EN 1996-1-1: Design of masonry structures - General rules
- TS EN 13369: Common rules for precast concrete products
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