• An improved and fully working model of a manually operated stone crusher, with a high yield of multiple sizes, as well as correctly sized stones.
• It should run without the use of electricity or petrol. It must be easy to maintain and easy to repair.
• Added to, or perhaps integrated into the design, must be a device that separates the stones at input level, as well as at the output level.
• Do-it-yourself guidelines for assembling, maintenance and calibration of the machine.

Open for students and professionals of Mechanical, Industrial and Product Engineering. Send us an email to request the full assignment sheet via this link.

Past and current research:
2008 – 2009: Demen Hartman
2011 – 2012: Tomas Carthy, University of Limerick
2014 – 2015: Declan Dunne, University of Limerick
2016 – 2017: Patrick Kenny, Sam Savage, Dominik Tokarski, Dublin Inst. of Technology

To make good concrete, the size of the aggregates must be around 20 mm maximum. The quality of concrete is even more critical in earthquake prone areas, where concrete elements must contribute to resisting the seismic forces on a building.

In many developing countries, especially in rural and remote areas, stones and aggregates are taken directly from the site. They are hauled from a nearby river or get hacked out of the mountain. People sometimes re-use stones from discarded buildings or try to crumble illegally duped construction waste.

To be properly mixed into the concrete, any type of stones needs to be broken into smaller pieces. Due to lack of electricity, gas or petrol, this is often done by hand. But this breaking process is slow, and often the aggregates are still too large in size. When too big stones are used in concrete, the mixing will be bad, and this results in poorly cast beams with insufficient strength.

Hence the need for a solution to produce correctly sized and shaped aggregates for concrete applications.