In late June 2021, we were all shocked by the apartment building collapse in Miami FL and the tremendous loss of life. While this was a tragic accident, it was avoidable. This article explains some of the root causes of the tragedy and steps that can be taken to avoid future and pending occurrences. Simply put: Steel and concrete and saltwater do NOT mix.
Corrosion, spalling, cracking, failure, and collapse are the results of steel in concrete over time.
Steel and 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.
Basalt Rebar – A Simple Solution to a Longstanding Problem
I have shown construction engineers on our local bridge how adding basalt rebars and better concrete with far more impermeable properties could significantly lengthen the life and lessen repairs. In a meeting in front of everyone an official said, “We will not use those products because we will run out of work”! Wow!
We have hundreds of years of work to do if we started yesterday.
Putting good steel deeper in the core of a structure — like stainless or galvanized MMX type and then surrounding the outer sections close to the surface with Basalt volcanic rock fiber reinforcements are a solution for ALL concrete. We then would not have the spalling seen today everywhere. 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.
Cost Considerations
It is perceived that the approach might cost a little more to begin but the long-term costs are far less. And today, Basalt rebar is less expensive than its steel counterpart.
Sensible design engineering will incorporate FRP (BFRP for basalt) into buildings of the future. More geopolymer cements, as well as high and ultra-high-performance, concretes which do not allow chloride ingress – enhanced with basalt instead of steel is the best solution.
Additives to stop water penetrations are now available, and pozzolanic additives for strength also.
Pilings, foundations, slabs, and balconies that today are all prone to failure over time need to be re-engineered with the materials we have which have been proven.
Basalt mini-bars are also now available as toothpick-size macro fibers. These 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 as now lifespan is a huge part of costs.
Build new and repair existing with basalt reinforcements!
Most all DOTs have expressed that a huge portion of their budget is on repairs rather than on new builds. Especially those states near saltwater or using road salts for deicing.
Instead of engineers specifying ONE or the other, it is time to understand that including FRP (BFRP) for basalt with steel for high strength long-lasting bridge and road work is a key solution. Again, better add mixes, macro fibers, better steel and better concretes with Basalt reinforcements are the answer. There is no longer any need to go looking for these solutions as the testing and data are known.
Materials Science
Basalt is rock and the fibers being rock, expand and contract at the same rate as concrete, unlike steel. Cold temperatures in the morning followed by very warm temperatures in the afternoon cause expansion and contraction. These make fine cracks in concrete. Small cracks become bigger ones. Water penetrates, ice can form, and the corrosion increases, little by little until the rust has nowhere to go. The concrete pops open in bigger chunks. This is “spalling”. The capacity of the steel which with a little rust is fine and somewhat protected. However, as this rusting continues the steel no longer has the structural capacity needed. And then the problems are a lot more significant.
Wraps can be made of composite fibers like fiberglass and carbon fibers and basalt with epoxy to help mitigate the destruction. Carbon fibers are strong in one direction however they are electrically conductive and shatter on impact from the side. And it is very expensive. Fiberglass does not have the saltwater tolerance or chemical durability of basalt. Basalt fibers are over 24% higher flexural modulus of elasticity than fiberglass- stiffer.
Basalt fibers are hundreds of degrees hotter and colder temperature capable than fiberglass. Being rock also they are more easily recyclable. Basalt takes wide impact better than most other fibers by far. It is UV immune, easy to work with and apply resins too, and cuts nicely. Basalt volcanic rock fibers are the answer for longevity, security, and affordability.
Spalling – We’ve all seen it
I am showing some examples of what we have all seen under bridges and along highways of this spalling of concrete and steel.
I am quite sure we all do not want to drive over these bridges with heavy trucks. Or live in a building with this holding it up. No longer is it acceptable to continue to do the wrong thing when we know there are alternatives and the cost of doing things right is less in total by far.
Rethinking and Rebuilding
Our new infrastructure budgets can help repair with adequate solutions. But additionally, we must school and train new engineers to think differently. And they, in turn, will begin to build differently; Change will come.
They only know what they are taught and only stamp engineering plans according to the codebooks. However, the time has gone on far too long; now is the time to change these codes. The train is leaving the station, and the materials we know now exist are ready to be included. Again, not to exclude the decades of proven capacity of steel and concrete, but to enhance them significantly.
Buildings, bridges, dams, roads, highways, and all the support systems made with concrete can be far longer-lasting, lighter, and more robust. For example, bridge decks have been completed successfully with FRP, and the railings on these can be all composites.
Use the right materials – Cost and Repair Avoidance
Why pay every couple of years to sandblast and repaint railings that can be stronger and lighter than steel and never have to be repainted?
Foam core reinforced composites can replace many concrete sections and last much longer. Tunnels can be made or coated with ultra-high-performance concretes reinforced with basalt macro fibers, rebar, and mesh. Using this approach, these tunnels will not allow for chloride penetration that causes ultimate destruction. Candy coating strong concretes with this technology is an affordable solution.
Far more flexural ductile concretes can handle earthquakes and hurricanes.
Underground piping enhanced with these products will handle stresses and be safer while lasting decades longer.
Many buildings hundreds to thousands of years old in Europe are standing because they did NOT have steel reinforcements.
We are repairing historic building structures like cathedrals and mosques and significant sites all over Europe and the Middle East with basalt reinforcements because they do not corrode over time.
Domes, barrel vaults, arches, etc., all are far more structurally sound with the use of basalt fiber reinforcements or basalt rope. (We are currently helping restoration efforts in a number of historical buildings using these and other basalt products. Contact us for guidance.)
Oil and gas pipelines, even asphalt roadways, airport runways, and communications towers will benefit and be safer, including basalt volcanic rock fiber reinforcements while not cracking and corroding.
Advanced plant-based resins are now developed that are non-toxic and can be more easily disposed of at their end-of-life cycle.
New resins that are entirely non-toxic with no hazardous carcinogens are now available and, when mixed with basalt fibers, do not burn while emitting only water vapor.
Alternatives and Replacements
Replace petroleum base fibers with rock basalt fibers and these resins to make anything from boat hulls to truck and auto bodies.
Composites will become far more used in bridge designs like being done at advanced facilities.3D printing will soon be able to make much larger format structures like bridge sections that will have the internal geometry to support lighter and stronger materials (a major one being basalt fiber composites). All structures are based on geometry, and it is our belief that we will soon be using the computers and materials advances to bring infrastructure into a new realm.
Seriously reducing the amount of concrete which is one of the world’s most used materials and largest carbon emitter, is crucial. But, of course, making our roads, bridges, and buildings safer, more durable, and longer-lasting while being healthier is the goal.
As stated, better concretes, Geo-polymers and more robust, lighter, and longer-lasting reinforcements are here and ready to be included in the specifications.
It’s time for a change.
We need the government to embrace much more expeditiously these changes, to get behind them in a big way quickly as time is running out for slowly changing. Again, we are NOT recommending replacing the methods and materials of today everywhere but enhancing them, enveloping them with the longer-lasting materials and solutions available now.
In time composites will possibly eliminate a great portion of the concrete used now, and our aim is to be a good part of that.
Let’s train the designers of tomorrow and educate those in charge today on why this is needed and how to implement these changes.
Time is a precious commodity. Let’s roll now.
We make composites ROCK!