Geopolymer
An inorganic binder that hardens when mineral powders rich in silicon and aluminum react with an alkaline solution. Once hardened, it holds aggregate particles together, as cement does.
CORE C-ZERO BLOCK
An eco-friendly permeable paving block made with recycled inorganic aggregate produced from sewage sludge incineration ash, bound with a geopolymer in place of cement
Problem
Sewage sludge incineration ash with nowhere to go
Sewage sludge is the residue left after household, commercial, and industrial wastewater is treated before it is discharged into rivers. Since ocean dumping was banned in 2012, sludge has been incinerated at high temperatures to reduce its volume, but the remaining ash is running out of places to be buried as landfills reach capacity.
Impermeable paving, urban flooding, and heat islands
Asphalt and concrete pavements prevent rainwater from soaking into the ground. Rainwater runs off all at once, raising the risk of flooding, and as the ground holds less water, urban temperatures rise.
Limitations of conventional paving blocks
Conventional paving blocks are made with natural aggregate and cement, so rainwater does not soak through easily and efflorescence occurs. Recycled permeable blocks also use cement as a binder.
| Conventional paving block | Recycled permeable paving block | CORE C-ZERO BLOCK | |
|---|---|---|---|
| Core materials | Natural aggregate + cement | Recycled aggregate + cement | Recycled inorganic aggregate + geopolymer |
| Permeability | 0.1 mm/s | 1 mm/s | 1.4 mm/s |
| Carbon emissions | 100% (baseline) | 80–90% | 60% or less |
| Durability and performance | Efflorescence | Heavy metal leaching | Antibacterial · heavy metal ion adsorption |
Product
A permeable paving block that replaces part of the aggregate with sewage sludge incineration ash and the cement binder with a geopolymer.
Inorganic aggregate from resource circulation
A zero-waste raw material that uses sewage sludge incineration ash, a waste once sent to landfill, as aggregate.
Sewage sludge incineration ash paving block
A low-carbon paving block made through the chemical bonding of inorganic aggregate and a binder.
Non-cement inorganic binder
A geopolymer binder that chemically bonds inorganic particles and hardens them like stone, without cement.
How the raw materials of CORE C-ZERO BLOCK differ
Hover over or tap a material to see a short explanation.
Standard paving block
CORE C-ZERO BLOCK
Aggregate · The structural framework of the block. Standard blocks use sand and gravel.Binder · Binds the aggregate together and hardens it. Standard blocks are hardened with cement.Aggregate · Ash left over from incinerating sewage sludge. Ash that was once discarded becomes the framework of the block.Binder · A binding technology that hardens minerals without cement.
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- Aggregate · Sand and gravel
- The structural framework of the block. Standard blocks use sand and gravel.
- Binder · Cement
- Binds the aggregate together and hardens it. Standard blocks are hardened with cement.
- Aggregate · Incineration ash
- Ash left over from incinerating sewage sludge. Ash that was once discarded becomes the framework of the block.
- Binder · Geopolymer
- A binding technology that hardens minerals without cement.
- Voids
- The path rainwater takes through the block and down into the ground.
Why cement is not used
Cement is made by firing limestone at high temperatures, a process that releases large amounts of carbon dioxide. Geopolymer is a binder made without firing limestone, which is why it has been studied as an alternative to cement.
Permeability of CORE C-ZERO BLOCK
Standard pavement (asphalt, concrete)Rainwater pools
The pavement blocks the water, so rain pools on the surface and then runs off to the side.
Permeable blockRainwater soaks in
Rainwater passes through the blocks and soaks into the ground below.
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Permeability coefficient
KS F 4419 · Korea Conformity Laboratories (KCL)
(requirement for permeable blocks: 0.1 mm/s or more)Flexural strength
KS F 4419 · Korea Conformity Laboratories (KCL)
(KS F 4419 requirement for permeable blocks for sidewalks: 4.0 MPa or more)Lower CO2 emissions
Uses geopolymer bonding instead of cement
to reduce carbon dioxide emissions compared with conventional paving blocks.Lower waste landfill costs
Uses sewage sludge incineration ash as aggregate
instead of sending it to landfill, reducing landfill costs.Antibacterial
An antibacterial paving block with a 99.9% kill rate against E. coli, Pseudomonas aeruginosa, and Staphylococcus aureus.
Patents
RegisteredPatent
Paving block using sewage sludge and method for manufacturing the same
- Registration No.
- No. 10-2682060
- Registered
- 2024.07.02
- Application No.
- 10-2023-0088345
- Filed
- 2023.07.07
- Holder
- CORE26 Co., Ltd.
PendingPatent
Porous bio-block using sewage sludge incineration ash and method for manufacturing the same
- Application No.
- 10-2026-0159873
- Filed
- 2026.08.25
PendingPatent
Eco-friendly antibacterial paving block using sewage sludge incineration ash and geopolymer, and method for manufacturing the same
- Application No.
- 10-2026-0172488
- Filed
- 2026.09.10