The Masonry Workforce and Automation

The masonry workforce faces shortages as it enters the future. Retiring masons are not being replaced by younger masons at an equal rate. The result is that the supply of skilled masonry workers does not meet the demand for this critically necessary skilled workforce to assemble masonry buildings and structures. This is not a sudden development; the industry has been aware of this troublesome trend for decades now. We need more masons.

Many commendable efforts are underway to recruit new masons into this important workforce, including efforts by the International Union of Bricklayers and Allied Craftworkers (BAC) and BAC’s educational and training organization, the International Masonry Institute (IMI). Additional recruitment efforts to help grow the skilled masonry workforce are underway by the Mason Contractors Association of America (MCAA) and several other regional and local masonry education and recruitment organizations.

Regardless of these excellent efforts to recruit new masons to the workforce, the supply of new masons simply does not meet the current demand for masons, nor is it expected to meet the growing demand in the future. What will be done to help supply the demand for masonry construction?

Part of the answer is to provide the masonry workforce with the tools, materials and techniques which will make human masons more efficient. This includes semi-automated methods and more fully automated assembly methods and equipment to help meet the demand for beautiful masonry buildings.

This includes lift-assist technologies, such as the MULE (Material Unit Left Enhancement) provided by Construction Robotics, to help masons work faster and more efficiently. It also includes exoskeletal equipment, provided by several companies, which are attached to the body of a human mason. It also includes much more fully automated systems, such as Fast Brick Robotics’ (FBR) “Hadrian X” robotic assembly system. The Hadrian X does not use mortar, but rather employs construction adhesive instead. At some point, this is no longer traditional masonry (without mortar) but becomes something else.

In my own experience, there has been resistance in the industry to adoption of semi-automated and fully automated masonry assembly methods and equipment. This is understandable! Masons don’t want to lose their jobs and be replaced by robots. The beauty of block requires the touch of a human mason.

Our company (Spherical Block, LLC) has been investigating new technologies, with a focus on semi-automated assembly tools and materials, for over a decade. I addressed this when I was invited to be keynote speaker at the North American Masonry Conference by The Masonry Society (TMS) in 2019, and was asked to talk about “Innovation in Masonry Today.”

Interest in these approaches has been growing slowly and steadily over the years. The path forward includes those processes and equipment which can help assemble masonry faster, more safely and more efficiently while providing the beauty of block to our buildings well into the future. This will require human masons, and the value that they add to our built environment. Using new tools, techniques and materials, masons will add even greater value to the world of construction. 

 

Stronger support for ocean front homes and buildings

Houses and buildings located along coastal areas are often susceptible to storm surges of ocean water, especially during hurricanes and extreme weather events. The damage done by this violent weather can be exacerbated by high tides.

These buildings are typically placed atop wooden posts and pilings. This configuration allows a storm surge to pass under the building, so that the building itself is not struck by the full force of a storm surge.  The forces of wind, water and wave are unrelenting for a building located along coastal plains, with a close proximity to the ocean. They are constantly under a barrage or attack by the forces of nature.

As Sea Level Rise (SLR) increases, the effects of wind water and wave are more pronounced on waterfront properties. Failure of the support systems currently used to keep these buildings above the plain of storm surge have become more common. It is expected that this situation will become more widespread and increasingly worse as SLR continues. Recently, failure of these support structures has taken place, especially on the Outer Banks of North Carolina. An article in today's USA Today (May 29, 2024) describes some of this damage.

There is a better way to keep a building located in a coastal plain elevated, other than the old, vulnerable method of using wooden posts. High-strength masonry arches, made with an appropriate concrete mix, and reinforced with basaltic FRP (Fiber Reinforced Polymer) rebar provide a very stable configuration. The high strength of concrete exceeds the strength of wood. The proper concrete mix, suitable for marine environments, can last much longer than a piece of wood. The arch configuration of this type of support structure is better able to withstand the lateral forces which are created by waves, wind and water; much stronger and more robust than vertically placed wooden posts.

This method can be rapidly assembled (done in just a few days), it is cost competitive with wooden posts, and it creates a visually striking pedestal for the building. The arches also provide easy access for parking, so the area underneath the building can be readily used.  Any number of platforms can be placed on top of the arch support structure, including reinforced flat concrete slabs, bubble decks, post-tensioned slabs, and so on.

Last summer, we made a concrete ping pong table (table tennis) out of concrete. The legs for the table were made as arches. using basaltic FRP rebar, cast within the concrete forms. This served as a scale model for a structure which could be used to support a building in a coastal plain, subject to storm surges, wave, wind and water. One can imagine this configuration made around 10 times larger; it would provide the perfect platform for building a house in a coastal flood plain, with parking underneath. 

The scalability of these designs is easy to grasp, if one looks at some of the larger arches made from our "Arch" block, which is assembled with 3 pieces of basaltic FRP rebar, as shown below (this shows a 30 ft. span). This configuration is very strong.  The straight sections, or legs, as shown on the corners of the ping pong table can be made from regular CMUs, where the hollow cores are reinforced with grouted FRP rebar. 

This method will allow houses to be built on very strong, affordable, long-lasting, elegant support systems which will allow them to survive further into the future in coastal areas prone to storm surges which are vulnerable to SLR. This will make coastal homes more resilient.

Making a concrete ping pong table

I recently completed making a concrete ping pong table. It came out pretty well, and I look forward to playing some ping pong!

Here are the basic steps I took to make and assemble the ping pong table.

First, I made wooden molds. There was a mold made for the table surface, a mold made for the central supporting arches, and four molds for legs which spring from the arches to the corners of the tabletop. Here are the molds, shown upside down.

Here is the arch section being made. There are 4 pieces of #3 rebar (3/8 inch diameter) in the arch form.  I used basaltic FRP rebar (fiber reinforced polymer).  All reinforcement was kindly donated by Nick Gencarelle of Smarter Building Systems. Nick is very knowledgeable and helpful.  We just used a bagged concrete mix, specified as having a strength of 4,000 psi after 28 days of curing.

Here are the four legs being made. Each leg also has 4 pieces of #3 FRP rebar.

Next, we set up a form for the base. The same form was used later for the tabletop. We placed #3 FRP rebar inside the form, at 10 inches on-center.  The arch form and leg forms were placed and cast directly in the concrete of the base.

After the base cured for a few days, we set up the mold for the tabletop. The mold was filled with basaltic FRP mesh reinforcement and also #3 FRP rebar, for tensile reinforcement.  The rebar was located so that it aligned with the legs underneath, for strength. The entire mold was greased with Crisco, used as a mold release agent. A sheet of plastic was placed on top of the wooden form, to help the concrete release from the mold.

The mold was then filled with concrete, with particular attention to place some concrete under the rebar, to help provide proper cover.  The concrete was then screeded (spread evenly with a straight piece of wood, moved back & forth as it is drawn across the form).  This surface was then floated, or smoothed out by hand.  The edges of the form were all vibrated. In this case, we did not have a proper concrete vibrator, so we used a "sawzall" reciprocating saw, which worked pretty well.

Properly floating the surface is important to get a nice, smooth, flat finish.  It is worth spending some time and doing this properly.

The form was then covered and allowed to cure for a full week. It helps to cover the concrete with plastic, so that water remains in the curing concrete to form hydration products.

After one full week, the wooden forms were removed. We also did some landscaping, to create a level playing surface on the ground around the table; this involved a retaining wall being placed also.  This work was simply done with a pick, shovel and rake. It took an afternoon. 

Now, it just needs a net! I will also use a sealant to help protect the concrete from the weather, something like Thompson's Water Seal.  This will also make a great picnic table. I expect it should last a long time. We will also plant some grass on the fresh dirt.

This basic concept could be made much larger, to provide an elevated platform to build homes on. We could use my company's masonry arch system to accomplish this, easily and quite affordably.  This would be appropriate for coastal areas which are prone to storm surges and flooding from hurricanes and severe weather. It is stronger than the wooden posts currently used to elevate homes above a storm-surge plain, and will not rust or rot, like wood. It is also more elegant and looks much better than those wooden posts.

This table cost about $150 in concrete.  The rebar is also inexpensive. If anyone wants a concrete ping pong table and would like to borrow my molds, you are welcome to.  Just let me know.

This thing should be fun, I look forward to using it!

A recent video

Recently some dear friends of mine completed a lovely video they made about me, my work and my company.  This work was done by Burton Stein, his daughter Autumn Layne Stein, and Autumn's fiance, Matt Goodwin.  I am very grateful to them for this work. 

Here it is!  

Experimental prototype one-car garage

 I decided to make a concrete driveway at my property in Alfred, NY. It gets very muddy here, so a concrete driveway will be very helpful. I need the driveway to be strong enough to accomodate heavy trucks. It is 8 inches thick, with #3 (3/8 inch diameter) basaltic fiber reinforced polymer rebar, arranged every foot on center. I'm using 4,500 psi concrete, and doing pattern stamping with a "European fan" pattern, finished with coloring and finally sealed. 

I realized that I had to build a garage at the end of this driveway, beginning at the end. In the past month or so I assembled this prototype, in a simultaneous attempt at several new experiments.  

The garage is 12 ft. wide, 20 ft. deep, and 8 ft. tall at opening. FRP rebar is located every 8 inches, in walls and arch.

Concrete block are anisotropic, which means that they are stronger in one direction than another. They are much stronger in compression in the axis of compaction during their manufacture. The strength increase is around 70% higher along the axis of compaction. Regular CMU walls have this high-strength axis oriented vertically, up-and-down. This means that the weak axis is oriented horizontally. In cases where high strength is desirable in the horizontal direction, such as tornadoes, hurricanes, extreme weather events, and especially waves or driven water, it could be advantageous to have the high-strength axis oriented horizontally.

Anisotropy in manufactured block occurs because aggregate aligns itself preferentially, normal to, or at 90 degrees to, the applied force during violent vibrational compaction of concrete mix in a mold to form the CMU. Here are some optical micrographs taken from a CMU, showing preferential orientation of aggregate.

The walls of this prototype building have the high-strength axis oriented horizontally. There are no hollow cores, it is solid 8 inches of reinforced concrete. Shown below is an improvized 'bond beam' for additional lateral strength; there are 2 rebar emedded in the mortar joint. Such a building should be capable to withstand tornadoes, hurricanes and wildfires.

The roof will have the block oriented radially, toward the outside, so that this high-strength axis feature is maximized. I am getting ready to build the masonry arch roof, which springs from cast reinforced skewback/bond beam at the top of the vertical wall. Inside the building at the top of the vertical walls are horizontal rebar crossing the span, for additional tensile reinforcement.

I will post updates as this project is completed. It's going pretty quickly, and I'm just working alone: moving block, mixing mud and tending myself. One block at a time.