A jaw crusher reduces material by compressing it between a fixed and a moving plate. An impact crusher throws it against blow bars and then against the chamber walls. The two mechanisms respond very differently to rebar, asphalt, abrasive rock and moisture.
Where a jaw crusher wins
- Abrasive rock — granite, basalt and quartz wear impact blow bars quickly; jaw plates last far longer per tonne.
- Very large feed — feed openings such as the 700×1060 mm chamber on the UJC106 swallow blocks that would need pre-breaking for an impactor.
- Sticky or wet material — compression is far less sensitive to moisture than impact.
- Lowest cost per tonne in hard rock — fewer wear parts and simpler maintenance.
The trade-off is product shape: jaw output is flakier and contains more oversize, so a secondary crusher or a closed-circuit screen is often added where aggregate specification matters.
Where an impact crusher wins
- Reinforced concrete — the striking action breaks concrete off the rebar instead of stalling on it; a magnet then removes the steel.
- Asphalt — recycled asphalt pavement keeps its binder properties better when reduced by impact.
- Product shape — a higher proportion of cubical particles, valuable for concrete aggregate.
- High reduction ratio — one pass can go from demolition slab to saleable sub-base.
On a demolition site with mixed feed, a machine such as the UHC600 tracked impact crusher is often the only unit that can handle rebar-laden slabs without constant intervention.
A practical decision list
- Mostly clean, abrasive natural rock → jaw.
- Mostly reinforced concrete, asphalt or mixed C&D waste → impact.
- Hard rock plus a need for shaped aggregate → jaw followed by a cone or impactor in closed circuit.
- Very wet, sticky feed → jaw, and screen the fines out first.
Matching the downstream equipment
Whichever you choose, the machine's output has to be graded and stockpiled. A typical demolition line pairs the crusher with a scalping screener to remove fines, a grading screen for sized products, and stacker conveyors for stockpiles. Shredders such as the UMS950 mobile shredder are added where bulky waste, timber or green waste is part of the feed.
Key takeaways
- Compression for abrasive, wet and very coarse feed; impact for reinforcement, asphalt and shape.
- Estimate wear cost per tonne for your actual material before choosing.
- Plan the screening and stockpiling equipment at the same time as the crusher.
Send us a sample description or a video of your feed, and we will tell you which mechanism fits. Request a recommendation.