Fly Ash Bricks | WSB Infra & Crafts

What Are Fly Ash Bricks?

Fly ash bricks are masonry units manufactured using fly ash — a fine, powdery by-product collected from the flue gases of coal-fired thermal power plants — combined with lime, gypsum, and sand or stone crusher dust. The mixture is compressed under high pressure (350 kg/cm²) in hydraulic machines and then steam-cured to produce dense, uniform, high-strength bricks.

India's thermal power plants generate over 200 million tonnes of fly ash annually. By converting this industrial waste into construction-grade bricks, we prevent environmental pollution from ash ponds while conserving precious topsoil used in clay brick manufacturing. Fly ash bricks account for approximately 1/6th of India's annual brick production and are approved by IS 12894, CPWD, and most state PWDs for masonry construction.

Manufacturing Process

Our bricks are produced through a precisely controlled, quality-assured manufacturing process.

01

Raw Material Proportioning

Fly ash (50–60%) + Sand/Crusher dust (20–30%) + Sludge lime (15–22%) + Gypsum (5%) are precisely weighed and fed into a pan mixer. Mixture moisture is maintained at 10–15% for optimum compaction.

02

Mechanical Mixing

The dry ingredients are mixed for 4–6 minutes in a heavy-duty pan mixer or paddle mixer. Water is added gradually to achieve a homogeneous, lump-free consistency with uniform colour distribution.

03

Hydraulic Press Moulding

The mixed material is fed into automatic hydraulic brick presses with 350 kg/cm² compaction pressure. Each cycle produces 6–12 bricks with precise dimensional tolerance of ±2 mm. Moulds are lubricated for clean release.

04

Steam Curing

Green bricks are transferred to steam curing chambers maintained at 66°C for 24 hours. The controlled heat and humidity accelerate the pozzolanic reaction between fly ash and lime, developing 70% of final strength within 48 hours.

05

Water Curing

After steam curing, bricks undergo 7–14 days of water curing on pallets where they are kept consistently moist. This ensures complete hydration and achieves the specified compressive strength.

06

Quality Sorting & Dispatch

Every batch is tested for compressive strength (digital CTM), water absorption (24-hour immersion), efflorescence, and dimensional accuracy. Inspected bricks are sorted, shrink-wrapped on wooden pallets, and dispatched.

Technical Specifications

All our fly ash bricks conform to IS 12894 and are tested in our in-house QC laboratory.

Parameter	Specification
Standard Size	230 × 110 × 75 mm (nominal) — other modular sizes available on request
Compressive Strength	7.5 – 15 N/mm² (MPa) depending on grade — tested as per IS 3495 Part 1
Water Absorption	< 15% by weight after 24-hour immersion — tested as per IS 3495 Part 2
Efflorescence	Nil to Slight (Class 0 or Class 1) — tested as per IS 3495 Part 3
Density	1,500 – 1,800 kg/m³
Thermal Conductivity	0.45 – 0.60 W/mK (vs. 0.80–1.20 W/mK for clay bricks)
Sound Insulation	40 – 45 dB for 230 mm wall (vs. 35–40 dB for clay brick wall)
Dimensional Tolerance	± 2 mm in length, width, and height
Weight per Brick	2.8 – 3.2 kg (vs. 3.0–3.5 kg for clay bricks)
Fire Resistance	Superior — fly ash bricks are inorganic and non-combustible; 2–4 hour fire rating depending on wall thickness
Applicable Standard	IS 12894:2002 — Fly Ash Lime Bricks — Specification
Mortar Required	30–40% less mortar due to uniform shape and smooth surfaces
Plaster Thickness	10–12 mm (vs. 15–20 mm for clay bricks) — consistent surface requires less plaster

Why Choose Fly Ash Bricks Over Clay Bricks?

Fly ash bricks offer measurable advantages in strength, cost, and environmental impact.

Eco-Friendly

Each fly ash brick diverts 2.5 kg of industrial waste from ash ponds. No topsoil is consumed — preserving agricultural land. Embodied carbon is 40% lower than clay bricks.

Higher Strength

Compressive strength of 7.5–15 MPa versus 3.5–7.5 MPa for typical clay bricks. Stronger walls, less breakage during transport (< 2% vs. up to 10% for clay bricks).

Better Insulation

50% lower thermal conductivity than clay bricks means cooler interiors in summer and warmer interiors in winter — reducing HVAC energy consumption by 15–20%.

Cost Savings

Uniform size reduces mortar consumption by 35%. Less plaster required (10 mm vs. 18 mm). Faster construction — saves labour costs and project time.

Lightweight

10–15% lighter than clay bricks — reduces dead load on the structure. Ideal for multi-storey buildings where foundation savings add up significantly.

Uniform Dimensions

Precision hydraulic moulding ensures every brick is exactly 230×110×75 mm (±2 mm). No distorted or oversize bricks — cleaner, straighter walls with fewer joints.

Common Applications

Fly ash bricks are suitable for all types of masonry construction.

Residential

Housing & Apartments

Load-bearing and partition walls in affordable housing projects, high-rise apartments, and individual homes across multiple government and private developments.

Government

Institutional Buildings

Schools, hospitals, PHCs, community centres, and office buildings under CPWD, State PWD, and municipal contracts where IS 12894 compliance is mandatory.

Industrial

Factory & Warehouse Buildings

Compound walls, security cabins, office blocks, and industrial masonry — providing fire-resistant, durable enclosures for manufacturing facilities.

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