mineral / Cementitious / Concrete Masonry Unit

Lightweight concrete block, 390x190x190mm (190mm wall thickness)

390 x 190 x 190 mm hollow lightweight CMU (Adbri Litec 200 series). Unit weight ~12.2 kg; f'uc ≥ 15 MPa; thermal conductivity ~0.35–0.55 W/mK; fire insulation 120 min (hollow non-loadbearing) to 240 min (solid/grouted loadbearing). Complies with AS/NZS 4455.1 and AS 3700.

Atlas code

MIN-CEM-CMU-004

mineralcementitiouslightweightmasonryconcrete-masonry-unitCMULitec

Lightweight concrete block, 390x190x190mm (190mm wall thickness)

At-a-glance signals

Overview

Executive summary

Litec 200 series lightweight concrete blocks are 390 x 190 x 190 mm masonry units manufactured by Adbri Masonry. Made with concrete mixes incorporating lightweight industrial by-products — typically expanded clay (Leca), pumice, or slag aggregate — they are 25 to 30% lighter than standard-weight concrete masonry units. The reduced self-weight eases site handling, lowers structural dead loads, and delivers measurably better thermal performance (k ~0.35–0.55 W/mK) compared to normal-weight CMU (k ~0.8–1.2 W/mK). Fire resistance ratings of up to 240 minutes are achievable for loadbearing walls, and the Exposure durability grade meets AS/NZS 4455.1. Adbri Masonry's Litec range is widely distributed across eastern Australia and is a common choice for low-to-medium-rise residential and commercial construction where weight saving, thermal performance, and fire compliance are priorities.

Best when…

25–30% lighter than equivalent normal-weight CMU (unit weight ~12.2 kg vs ~16–18 kg), reducing bricklayer fatigue and manual handling injury risk.
Significantly improved thermal performance — effective thermal conductivity ~0.35–0.55 W/mK versus ~0.8–1.2 W/mK for normal-weight CMU, reducing heating and cooling loads.
Non-combustible mineral composition; achieves fire resistance ratings to FRL 240/240/240 (loadbearing, grouted) under AS 1530.4 and AS 3700.
Manufactured with lightweight industrial by-products (expanded clay, slag), incorporating recycled/waste streams and reducing virgin material consumption.
Compatible with standard 400 x 200 mm masonry module — direct dimensional substitution for normal-weight CMU with no design coordination changes.
Accepts N12/N16 reinforcement in hollow cores; can be fully grouted for reinforced masonry construction under AS 3700.
Hollow-core geometry reduces material use and self-weight while cores can be used as service conduit channels before grouting.
Complies with AS/NZS 4455.1 Exposure durability grade, suitable for sheltered to partially exposed above-ground applications without surface treatment.
Durable 100-year service life expectancy in normal above-ground environments with low maintenance once rendered or painted.
Broadly available through Adbri Masonry distribution network across eastern Australia; standard stock item at major building suppliers.

Top advantages

01 25–30% lighter than equivalent normal-weight CMU (unit weight ~12.2 kg vs ~16–18 kg), reducing bricklayer fatigue and manual handling injury risk.
02 Significantly improved thermal performance — effective thermal conductivity ~0.35–0.55 W/mK versus ~0.8–1.2 W/mK for normal-weight CMU, reducing heating and cooling loads.
03 Non-combustible mineral composition; achieves fire resistance ratings to FRL 240/240/240 (loadbearing, grouted) under AS 1530.4 and AS 3700.
04 Manufactured with lightweight industrial by-products (expanded clay, slag), incorporating recycled/waste streams and reducing virgin material consumption.
05 Compatible with standard 400 x 200 mm masonry module — direct dimensional substitution for normal-weight CMU with no design coordination changes.

Top limitations

01 Lower compressive strength than normal-weight CMU at equivalent density — standard lightweight CMU typically achieves 5–10 MPa, limiting loadbearing height without fully grouted or reinforced construction.
02 Higher water absorption (8–12% by mass) compared to normal-weight CMU (~5–8%), requiring sealing or render to resist moisture ingress in exposed locations.
03 More brittle and susceptible to chipping during handling and cutting; saw cutting preferred over hammer splitting to avoid block damage.
04 Porous surface requires priming or bonding agent before direct tiling, and may absorb excessive moisture from mortar coats if not pre-wetted.
05 Premium price over standard CMU — typically 15–30% more expensive per block due to the cost of lightweight aggregate processing.

Technical

Physical ·9

Density: 1200–1500 kg/m3 Gross wall density for 190 mm hollow lightweight CMU wall. Block unit density calculated from 12.2 kg unit weight and approximate gross block volume (0.390 x 0.190 x 0.190 = 0.01408 m3) = ~867 kg/block net; gross wall density including cores and mortar joints typically 1200–1500 kg/m3. AS/NZS 4455.1 classifies units with density < 1680 kg/m3 as lightweight.
Specific gravity: 1.2–1.6 Apparent specific gravity of the lightweight concrete mix (excluding hollow core air) is typically 1.2–1.6, consistent with classification as structural lightweight concrete (density class LC 1.2 to LC 1.6 per AS/NZS 4455.1).
Porosity: 20–35 % Total porosity of the lightweight concrete mix (not including hollow core void) is typically 20–35% for lightweight aggregate concrete, significantly higher than normal-weight concrete (15–20%). This elevated porosity contributes to the lower thermal conductivity and lower density, but also to higher water absorption.
Water absorption: 8–12 % by mass Lightweight aggregate CMU typically absorbs 8–12% by mass (compared to 5–8% for normal-weight CMU). AS/NZS 4456.17 test method applies. Elevated absorption reflects the porous expanded clay aggregate. Pre-wetting blocks before laying in hot/dry conditions is recommended to prevent rapid moisture draw from mortar. Render or paint sealing reduces in-service water ingress.
Hardness: 4–5 (approx) Mohs Concrete masonry surface hardness is not typically characterised by Mohs scale. Approximate surface hardness equivalent is 4–5 Mohs (calcite–apatite range), reflecting the hardened cement paste matrix. Lightweight aggregate (expanded clay) is softer than crushed stone, so surface scratch resistance is slightly lower than normal-weight CMU.
UV resistance: Excellent (inherent UV stability) Cement-based materials are inherently UV stable; there is no polymer binder to degrade under UV exposure. Unrendered lightweight CMU will experience minor surface discolouration (carbonation staining) over years of weathering but no structural degradation from UV. Painted finishes should be UV-stable exterior masonry paint.
Chemical resistance: Good (non-aggressive environments); Fair (coastal, sulphate-bearing soils) Good resistance to dilute acids, alkalis, and most organic chemicals. Sulphate attack is a risk in soils with high sulphate content — specify sulphate-resistant cement mix or external membrane in such conditions. Chloride penetration resistance is lower for lightweight CMU than normal-weight due to higher porosity; coastal applications within 100 m of surf require render protection and stainless or epoxy-coated reinforcement.
pH tolerance: 6–13 (service); 12.5–13.5 (internal pore solution) pH Freshly manufactured lightweight CMU has a highly alkaline pore solution (pH 12.5–13.5) due to calcium hydroxide from cement hydration. This passivates embedded steel reinforcement. Over time, carbonation lowers pH at the surface. For chemical resistance, CMU is suitable for pH 6–13; aggressive acid environments (pH < 6) require surface protection.
Surface roughness: 200–800 um As-cast (form-face) surface roughness of CMU faces is moderate due to the aggregate texture. Typical Ra (arithmetic mean roughness) is in the range of 200–800 µm for the open-textured face. This texture provides mechanical key for render adhesion without additional surface preparation.

Mechanical ·7

Tensile strength: 1.0–1.8 (estimated) MPa Direct tensile strength is approximately 8–12% of compressive strength for lightweight concrete, giving an estimated tensile strength of 1.0–1.8 MPa for a 15 MPa unit. Masonry walls are not relied upon for tensile resistance across bed joints without reinforcement; AS 3700 requires reinforcement or prestress for tension members.
Compressive strength: >=15 MPa Adbri Litec 200 full length hollow block: f'uc ≥ 15 MPa (unconfined compressive strength of individual unit per AS/NZS 4456.4). This is notably higher than typical generic lightweight CMU (5–10 MPa) and comparable to standard-weight CMU, achieved through mix design optimisation. Characteristic compressive strength of masonry (f'm) per AS 3700 Table 3.1 depends on mortar class; for M3 mortar with f'uc 15 MPa, f'm is approximately 5–7 MPa.
Flexural strength: 0.2–0.5 MPa Modulus of rupture (flexural tensile strength) for lightweight CMU masonry panels is typically 0.2–0.5 MPa depending on mortar type and bond. AS 3700 Tables 4.2 and 4.3 provide characteristic flexural tensile strength values (f'mt) for masonry perpendicular and parallel to bed joints. Lightweight CMU may have slightly lower f'mt than normal-weight CMU due to lower aggregate bond friction.
Shear strength: 0.15–0.25 MPa Characteristic shear strength of lightweight CMU masonry (perpendicular to bed joints) is typically 0.15–0.25 MPa for mortar-bedded construction per AS 3700. Lower than normal-weight CMU due to reduced block density and aggregate surface friction. Shear walls must be designed with reinforcement where lateral loads are significant.
Poisson's ratio: 0.15–0.20 Poisson's ratio for lightweight aggregate concrete masonry is typically 0.15–0.20, consistent with normal-weight concrete masonry and appropriate for elastic analysis under AS 3700.
Impact resistance: Moderate Moderate impact resistance — better than AAC (autoclaved aerated concrete) and similar to normal-weight CMU at equivalent thickness. Hollow cores reduce mass available to resist localised impact. Face shells can chip under hard point impacts (eg. fork-lift prong contacts). Impact resistance is adequate for all normal building occupancy situations; specialist impact-rated construction uses solid grouted or reinforced configurations.
Creep resistance: Moderate — higher creep than normal-weight CMU; movement joints recommended at floor levels Lightweight aggregate concrete exhibits higher creep than normal-weight concrete due to the more deformable porous aggregate. Long-term creep coefficient is approximately 1.5–2.5 (ratio of creep to elastic strain) for sustained compressive loads. In masonry walls, creep manifests as slow vertical shortening; movement joints accommodate this. Creep effects are generally small for typical low-rise loadbearing walls.

Sustainability & Health

Embodied carbon & energy ·7

Embodied carbon: 0.12 Estimated embodied carbon (kgCO2e/kg) for lightweight CMU. Cement production is the primary carbon source (~50% of embodied carbon). The use of industrial by-products as lightweight aggregate (expanded clay from waste clay sources, slag) reduces aggregate processing carbon. Estimated 0.09–0.14 kgCO2e/kg for the block, broadly consistent with ALCAS/AusLCI data for concrete masonry. EPD data from Adbri Masonry (Environmental Product Declaration, AIBN verified) provides project-specific values.
Carbon footprint: 125 Estimated carbon footprint (kgCO2e/tonne of block). Cement content dominates. A typical lightweight CMU mix uses 15–20% Portland cement by mass; at ~0.8–0.9 kgCO2e/kg cement, this contributes ~120–140 kgCO2e/t of cement. Supplementary cementitious materials (fly ash, slag) can reduce this by 20–40%. Total block carbon footprint approximately 100–150 kgCO2e/t.
Embodied energy: 1.5 MJ/kg Estimated embodied energy (GJ/t) for lightweight CMU. Expanded clay aggregate production requires kiln firing (~2.5–3.5 GJ/t of aggregate), which is the main energy-intensive step beyond cement manufacture. Total embodied energy of the block is approximately 1.3–1.8 GJ/t, slightly higher than normal-weight CMU (~1.2–1.5 GJ/t) due to aggregate processing energy, but offset over the building lifecycle by improved thermal performance reducing operational energy.
Water footprint: 180 L/kg Estimated water consumption (litres/tonne of block) in manufacturing, including mix water, curing water, and process water. Expanded clay aggregate kiln process requires some water for clay preparation. Block curing is typically ambient air cure (not steam or water ponding), minimising process water.
Recycled content: 30 % % recycled or by-product content by mass. Expanded clay aggregate is typically a processed natural material (not recycled), but some manufacturers use expanded slag (a by-product of steel making) or recycled glass foam aggregate. Supplementary cementitious materials (fly ash ~20%, slag ~30%) commonly replace Portland cement in the mix, contributing recycled content. Total recycled content estimate: 20–40% depending on formulation.
Renewable content: 0 % No renewable material content — all ingredients are mineral-based (Portland cement clinker, limestone, expanded clay or slag aggregate). No bio-based binders or renewable fillers.
Circular score: 7

Compliance & Fire

Fire performance ·5

Combustibility class: Non-combustible (AS 1530.1 / NCC Group 1) Non-combustible per AS 1530.1 (Methods for fire tests on building materials, components and structures — Combustibility test for materials). Classified as NCC Group 1 non-combustible material. Suitable for use in all fire-safety construction systems including tilt-up, loadbearing masonry fire walls, and compartment walls.
Fire resistance level: FRL –/120/120 (hollow non-loadbearing) to 240/240/240 (grouted loadbearing) minutes Fire resistance level (FRL) is system-specific per AS 1530.4 and AS 3700 Section 11. Adbri Litec 200 hollow non-loadbearing wall: insulation FRL 120 min. Grouted loadbearing 190 mm wall: FRL 240/240/240 achievable with appropriate cover and construction. FRL components: structural adequacy / integrity / insulation. Refer to Adbri Fire and Sound brochure for complete tabulated FRL data.
Flame spread index: 0 Non-combustible material; flame spread index = 0 per AS 1530.3 (Simultaneous determination of ignitability, flame propagation, heat release and smoke release). No surface flame propagation under any practical fire scenario.
Smoke dev. index: 0 No smoke development — non-combustible material generates no smoke or particulates from the block itself. Any smoke in a fire scenario originates from furnishings, finishes, or other combustible materials in the compartment, not from the CMU wall.
Heat release rate: 0 kW/m2 Zero heat release rate — concrete masonry is entirely non-combustible. Contributes no fuel load. Complies with NCC BCA Specification C1.1 Group 1 (non-combustible).

Cost & Lifecycle

Capex & lead time ·6

Material cost (range): $5–10 per block (trade, AUD, 2025) Supply price per block (390 x 190 x 190 mm lightweight CMU) at trade pricing in eastern Australia (2025). Retail price is typically $8–15 per block. Lightweight CMU is typically priced at a 15–30% premium over equivalent standard-weight CMU blocks. Price varies by region, supplier, and order quantity.
Material cost (per unit): $55–90 per m2 (blocks only, AUD, 2025) Indicative supply cost per m2 of 190 mm lightweight CMU wall (blocks only, excluding mortar, reinforcement, and grout). Based on approximately 12.5 blocks per m2 (390 mm x 190 mm face with 10 mm joints) at $5–10/block trade price. Wastage allowance 5–8% additional.
Lead time: 1–5 days Standard Litec 200 series blocks are held as stock items by Adbri Masonry and major building suppliers (Boral, Bowens, Tradelink Masonry) in eastern Australia. Typical lead time is 1–5 working days for standard orders. Large or project-specific quantities may require 2–3 weeks advance order for scheduling delivery.
Lifecycle cost: $350–550 per m2 over 50 years (AUD) Per m2 of finished wall over 50-year life, including initial material and installation, periodic repainting every 10–15 years (~$15–25/m2 per cycle), and minor crack repair. Masonry's inherent durability and low maintenance requirements make lifecycle cost competitive with lightweight framed alternatives. Excludes structural upgrades or retrofits.
Annual maintenance: $1.5–4 per m2 per year (AUD) Annual maintenance cost per m2 of rendered and painted lightweight CMU wall, averaged over a 15-year paint cycle. Includes pro-rated repainting ($15–25/m2 every 10–15 years) and allowance for minor crack and joint sealant maintenance. Unrendered exposed masonry requires less frequent maintenance (re-sealing every 10 years ~$3–5/m2).
Market availability: Widely available in eastern Australia Adbri Masonry Litec 200 series is widely stocked across NSW, VIC, QLD, SA, and WA through Adbri distribution centres and major building supply merchants. Equivalent lightweight CMU products are available from other manufacturers (Austral Bricks, Besser) in most states. Regional and remote areas may have limited stock and higher freight costs.

Service life & durability ·3

Expected lifespan: 100
Maintenance interval: 7
Warranty period: 10

Layer D

Where it's used

Loadbearing external walls (residential, 1–3 storeys)

Non-loadbearing fire-compartment walls

Rendered external walls (commercial)

Internal separating walls (Class 2 apartments)

Acoustic barrier walls (transport noise)

Reinforced retaining walls (≤1.8 m height)

Bushfire-prone area construction (BAL-FZ)

Commercial and industrial loadbearing walls

Boundary and fence walls

Energy-efficient residential construction (NCC Section J)

Where it's used

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