Green strength is the strength and shape stability that a freshly formed, not-yet-cured material has — the ability of “green” (young, wet) concrete, mortar or unfired stone to hold its shape before it is truly hard. The term “green” refers not to the colour but to the young, immature state of the material.
Where does green strength matter?
- Concrete — right after striking the formwork, or with precast elements, the concrete must already have enough green strength to support itself and be lifted
- Concrete blocks — after pressing, the still-wet blocks must be stable enough to be stacked and dried
- Brick — the unfired “green” brick (clay moulding) must be firm enough to be handled for firing
- Mortar — enough cohesion to stay in place and not slump
Importance
Sufficient green strength determines how soon work can continue:
- Striking time — the sooner the concrete holds its shape, the sooner the formwork can come off
- Production speed — in precast and stone production, good green strength speeds up throughput
- Quality — too little green strength leads to deformation, cracking or damage of young products
Green strength increases as the material cures, until the final (hardened) strength is eventually reached.
Related Terms
- Concrete
- Concrete mix
- Formwork
- Brick manufacture
- Compressive strength
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