First off we want to express our shock at the recent building collapse in Miami FL and our deepest condolences to the families and friends of those lost in this tragic incident.
Steel and Portland cement concrete and saltwater do NOT mix. Over time chloride attack penetrates porous concrete and rusts out the steel reinforcements that are critical to holding the excessive loads in a high rise building.
Structural engineers and builders used to not factor lifespan into the design of these buildings adequately. Frankly many builders figured 40-50 years later they would be gone and it became someone else’s problem, or it simply meant more work.
I showed construction engineers on our local bridge how adding basalt rebars and a better concrete with far more impermeable properties could significantly lengthen the life and lessen repairs. In a meeting in front of everyone a Union Rep said “We will not use those products because we will run out of work”!
We have hundreds of years of work to do if we started yesterday.
Putting a good steel deeper in the core of a structure — like stainless or galvanized MMX type — then surrounding the outer sections close to the surface with Basalt reinforcements is a solution. Why this has not already been integrated into new designs is puzzling.
Basalt rebar is 2-3 times stronger in tension than steel, yet over 70% lighter and will not corrode.
Basalt can be very close to the surface where a lot of structural forces are most needed. Having the steel deeper in the core and a better concrete with waterproofing additives and basalt all around is the best combination, and longest lasting solution.
It might costs a little more upfront but the long term costs are far less.
Sensible design engineering will incorporate FRP (BFRP for basalt) into buildings of the future. More geo-polymer cements, more high and ultra high performance concretes which do not allow chloride ingress – enhanced with basalt instead of steel is the best solution.
Pilings, foundations, slabs and balconies which today are all prone to failure over time need to be re-engineered with the materials we have, and have been proven.
Basalt mini-bars are also now available — toothpick size macro fibers — that can be used in slabs and completely eliminate rebar! Adding them in general would make whole sections of concrete more ductile, and significantly add tensile and elastic modulus.
It is time – lifespan is a huge part of costs. Build new and repair existing with basalt reinforcement!