Interlocking concrete block, 390x190x190mm (190mm wall thickness) | Material Atlas

Block · 390 × 190 × 190 mm

Cementitious — indicative fig. M·22

Fire A1 Non-combustible Embodied carbon Data pending Per-m² source Compressive 10–20MPa Structural Design life 100yr Durable

Mortarless interlocking 390x190x190 mm CMU system. Minimum compressive strength 10–20 MPa, dry density >1800 kg/m³, FRL up to 180/180/180 (grouted system). Faster installation than mortared blockwork; reduced skill requirement; approximately $4–8 per block ($40–90/m² supply) with lower labour costs than conventional CMU.

01 Physical

Density >1800kg/m3

Specific gravity 2.0–2.2 (solid material)

Porosity 12–18%

Water absorption 6–10%

Hardness 5–7Mohs

UV resistance Excellent

Chemical resistance Good (alkali/water); Moderate (mild acid); Poor (strong acid, sulfate soils)

pH tolerance 6–14 (service); pH 12.5–13.5 freshpH

Surface roughness 50–200um

02 Mechanical

Tensile strength 0.1–0.3 (unreinforced); reinforcement required for tensile loadsMPa

Compressive strength 10–20MPa

Flexural strength 0.20–0.36MPa

Shear strength 0.05–0.15 (ungrouted dry-stack); 0.3–0.6 (grouted reinforced)MPa

Poisson's ratio 0.15–0.20

Impact resistance Good (low-velocity); Moderate (hard-point impact — face spalling)

Creep resistance Good — low creep at service loads

03 Thermal

Thermal conductivity 0.5–1.3W/mK

Specific heat 840–1000J/kgK

Thermal expansion 8–12x10^-6/C

04 Compliance & Fire First question

Combustibility class Non-combustible (AS 1530.1)

Fire resistance level FRL 180/180/180 (grouted 190 mm system); up to 240/240/240 fully corefilledminutes

Flame spread index 0

Smoke dev. index 0

Heat release rate 0kW/m2

05 Sustainability & Health

Embodied carbon 160kgCO2e/m²

Carbon footprint 32

Embodied energy 1.1MJ/kg

Water footprint 180L/kg

Recyclability 100%

Recycled content 15%

Renewable content 0%

Circular score 7.5

VOC emissions 0

Toxicity rating Non-toxic (cured); alkaline irritant (fresh/cutting)

LEED contribution 3

06 Durability · Cost · Logistics

Expected lifespan 100

Maintenance interval 10

Warranty period 10

Material cost (range) $4–8 AUD per block

Material cost (per unit) $40–100 AUD/m2 (supply only)

Lead time 1–2 weeks (standard); 2–3 weeks (regional or specialty)

Lifecycle cost $350–500 AUD/m2 (50-year LCC)

Annual maintenance $0.30–1.00 AUD/m2/year

Market availability moderate–good (major cities); moderate (regional)

07 Assessment

Advantages

Mortarless dry-stack above first course — eliminates mortar mixing, reduces waste and speeds construction by 30–50 % compared with conventional CMU.
Reduced skill requirement: semi-skilled crew can achieve acceptable alignment and plumb without experienced blocklayers.
Self-aligning tongue-and-groove profile reduces the risk of course creep and provides consistent joint geometry.
Minimum unit compressive strength 10–20 MPa (system dependent); grouted system characteristic compressive strength 10.2 MPa per AS 3700.
FRL up to 180/180/180 (fully grouted system); integrity/insulation up to 240 min when fully corefilled.
High thermal mass (190 mm grouted wall ~350 kg/m²) supports passive solar design and reduces peak cooling loads.
Acoustic performance Rw 56+ suitable for party walls and boundary applications.
Non-combustible, inert — zero VOC, no off-gassing in service.
Long service life (50–100+ years) with minimal maintenance.
Readily available from national suppliers (Adbri, Austral Masonry); supply lead time 1–2 weeks.

Constraints

First course must be set in levelling screed or mortar to establish true datum — any error propagates through all courses.
Dimensional tolerance ±2 mm means minor face misalignment between courses; not suitable where flush fair-face finish is critical without grinding.
Core percentage >30 % reduces net section area; grouting is required for all structural and fire-rated applications.
FRL structural adequacy data is system-specific — consult manufacturer's Fire and Sound brochure; generic values do not apply.
Heavier individual unit (~15.6 kg) than lightweight CMU alternatives; manual handling limits productivity for single-person crews.
Limited range of surface textures and colours compared with standard CMU; specialist architectural finishes not generally available in interlocking profile.
Grouting operations constrained to 5–40 °C ambient — cannot proceed in frost conditions.
Cutting interlocking profiles with an angle grinder destroys the interlock feature; cut blocks must be placed at wall ends and corners where interlock is not required.
Higher unit cost than conventional CMU (saving is on labour, not material); not cost-effective for small areas where setup overhead dominates.
Not compatible with standard 10 mm mortar joint details; connection to adjacent mortared masonry, lintels and sills requires careful detailing.

08 Applications

A1 Residential loadbearing walls Single and two-storey loadbearing external and internal walls, grouted and reinforced to AS 3700

A2 Retaining walls Garden terracing, driveway cuts and site-levelling retaining walls up to 3 m engineered height

A3 Boundary and acoustic walls Sound barrier and security boundary walls; Rw 56+ satisfies NCC party wall requirements

A4 Garden walls and raised beds Landscape walling, raised garden beds, pool surrounds and outdoor living areas

A5 Steps and stair cheek walls External stairs, entry platforms and stair side walls

A6 Fire pits and outdoor fireplaces Non-combustible outdoor fire feature construction

A7 Commercial and industrial walling Warehouse, factory and commercial partition walls requiring fire rating and acoustic separation

09 Sources & Standards

Sources pending — citations for this material are not yet recorded. Verify all figures against manufacturer data and current standards before specifying.