r/science • u/mvea Professor | Medicine • Nov 03 '19

Chemistry Scientists replaced 40 percent of cement with rice husk cinder, limestone crushing waste, and silica sand, giving concrete a rubber-like quality, six to nine times more crack-resistant than regular concrete. It self-seals, replaces cement with plentiful waste products, and should be cheaper to use.

https://newatlas.com/materials/rubbery-crack-resistant-cement/
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u/SunSpotter Nov 03 '19 edited Nov 03 '19

Depends entirely on it's other material properties, and how it behaves under load. They made no mention to its compressive strength, which is probably one of the more important qualities of concrete so I'm skeptical.

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u/jbram_2002 Nov 03 '19

I tried to read the paper they linked, but strength data is hidden behind a paywall. If anyone knows the strength both in tension and compression, I would be interested to find out. My guess is this might potentially be stronger in tension and weaker in compression, if this has any strength benefits over standard cement. However, if they can attain a compression strength of 3000 psi, they can use this in a lot of situations. At 4000 psi, the majority of applications would be available.

One thing noted in the abstract (only free portion) was that the concrete performed significantly better when fiber-reinforced. This may make it difficult to use in some situations like roads and simple garage/foundation slabs, but wouldn't be a major issue for large building construction where fiber-reinforcing is already becoming more common.

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u/RuddeK Nov 03 '19

The ultimate compressive strength of the new concrete is more than 8700 psi (62 MPa to 71 MPa).

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u/canunu1 Nov 04 '19

Is that the strength with fiber reinforcement though? If so, it'd be nice to know the compressive strength of this concrete mix without the fiber reinforcement.

Sounds like it might have slightly less strength than current high strength mixes so the question then becomes the cost/availability question along with reliable strengths that will be used in calculations.