#Nighthawk #video on 50%-air to 75%-air aerated #concrete with “kitchen ingredients”; he likes 60% best. Specifically, he stabilizes the foam with pre-hydrated xanthan gum to keep it from collapsing while you’re mixing the cement. Dawn Ultra dish detergent (one part to 16 parts water) is his surfactant. Initially wetting the xanthan gum with “rubbing alcohol” (presumably isopropanol) helps a lot with wetting it; glycerin is apparently unnecessary. He thinks that this works because the xanthan gum slows the cement’s absorption of water.
on 02025-12-19#video of #Evan-and-Katelyn #manufacturing #concrete keycaps for a custom keyboard with PVA glue replacing some of the water in the cement (like a quarter or half or something), using personal vibrators to get the mix down into the keycap molds where they’re overmolding keycap stems made with #3D-printing. Also they tried adding 3% chopped fiberglass to their concrete mix, which is totally going to fail. They also tried adding more sand. To suppress bubbles, they loaded the keycaps into a pressure pot to cure. The fiberglass concrete wasn’t sandable, breaking apart. The PVA concrete felt “super hard and dense”. They also made the outside of the case out of concrete. It weighs three pounds, and the wrist rest another 1.7.
on 02025-09-28#video on #manufacturing a Le Corbusier style chaise longue from 19mm-thick #Portland #concrete reinforced with alkali-resistant chopped glass fibers and an alkali-resistant glass fiber scrim and an acrylic filler, laid over a #CNC routed MDF form.
on 02024-09-18#paper on #mechanical properties of #seacrete #materials as a possible replacement for #concrete, describing it as “electrolytically precipitated calcium carbonate”
on 02021-09-06Discussion thread on an article on #concrete as #weaponry or rather its opposite (in #Iraq)
on 02016-11-21"Carbonatation" of #concrete.
on 02016-06-26#Concrete #materials suffer #carbonatation more rapidly in today’s 400ppm CO₂ climate, and some #architecture designed for 75 years will start to fail in 50 or 60.
on 02016-06-26using #MICP with #Bacillus-pasteurii to heal cracks in portland-cement #concrete.
on 02015-11-03