My name is Brian Lywandowsky and I work for a large concrete construction company in the San Francisco Bay Area. I’ve worked in the concrete pumping business since I was sixteen. Since then, I have owned a small pumping business
with my father and in 2007, I moved onto the company where I work today. I currently manage the Concrete Pumping and Lightweight Cellular Concrete divisions.
In my years as an owner-operator of boom and line
pumps, I had some experience with shotcrete, with the
majority of it being in the pool industry. Most of the shotcrete
work I witness now is commercial work in the Bay
Area and Northern California that consists of perimeter
walls in subterranean parking garages, large shear walls,
columns, retaining walls, sculpted walls, and repairs on
bridges, just to name a few.
After spending time with the shotcrete crews in the
field, I was able to learn more about the industry from a
different point of view than just the pumping side of the
business. I was very impressed with how well the
shotcrete crews would perform their jobs on a day-today
basis. The crews would often arrive on a job that
was not set up or properly prepared. Many times, they
needed to set up the delivery line comprised of steel
pipe and rubber hose using unique techniques and with
a limited amount of time. Once the job was set up and
they could begin shooting, the crew would face less
than ideal conditions, such as improper tied reinforcing
bars, inadequately supported forms, and other obstacles.
This made it tough to shoot properly, not to mention
having to remove rebound from the work area to a
designated disposal location. However, the crews would
just put their heads down and go to work, producing a
fantastic end product.
The shotcrete crews have also done a great job
understanding what it takes to get the most out of the
pumping equipment. They’ve figured out that using
steel pipe on any pour that required more than 100 ft
(30 m) of delivery line would keep pumping pressures to
a minimum, create less breakdowns of the equipment,
and help get more volume of concrete placed per hour.
Using steel pipe from the back of the pump and limiting
the rubber hose is a huge help to the overall daily
production. It also helps eliminate premature wear of
the outside of the rubber hoses caused by the sliding
or sawing action produced by long runs and high line
pressure in a rubber-only delivery system.
Using the concepts I learned while owning and operating
concrete boom pumps, my experience could help
crews optimize the set up and cleanup of the pumping
system portions of the job. When starting a new project
with difficult conditions, we now show up with a truck
either a day or two before the job begins with all the
necessary pumping components. We’ll go ahead and
install the delivery system so we are ready to shotcrete
on shoot day. We designed specialized mobile parts that
clamp to solider beams, standpipe 90-degree elbows,
and brackets that can be bolted or welded to the existing
buildings or structures.
When on the job, I’ve seen many crews cleaning both
rubber and steel delivery systems with compressed air.
I believe this is the norm in the industry. The blowout
process crews used had likely evolved over time after
many near misses and hose whippings. Crews would
start by using air with no type of dart or plug to force the
concrete out of the system. This would serve to limit, but
not prevent, the amount of hose whippings at the end of
Fig. 1: Long vertical run of shotcrete line, “a shotcrete standpipe” Spring 2020 | Shotcrete 21
Fig. 2: Steel delivery line exiting pump
the line caused by the compressed air moving through
the line. The pump operator would unhook the system
from the pump and then use a blowout cap to push air
through the system, starting at the pump and blowing
the concrete out the end of the hose. Typically, the largest
guy on the crew would try to control the hose end
as the air was being applied to the delivery line being
cleaned out. He would hold the hose for dear life and
get a series of small but somewhat controlled explosions
of concrete at the end of the rubber hose. This went on
until more air than concrete was being expelled from
the end hose indicating the majority of the concrete was
cleared out of the system.
In the next step, the pump operator removed the
blowout cap and placed a small sponge in the line and
reattached the blowout cap to the pump end of the
hose. Once again, the man on the discharge end would
kneel on the ground with the hose running between his
legs or alternately trying to tie down the hose in some
way. He would then signal the operator to start the air
flow and hold on with a grip that was second to none.
By leaving a minimal amount of the concrete in the system,
it becomes much more difficult to be able to judge
where the sponge is within the system and how fast it
is traveling. As it travels closer to the end hose, it can
create hose whipping.
The use of compressed air to clear concrete from
the system is extremely dangerous. However, with the
proper training and correct parts, this process can be
safe, fast, and clean. The American Concrete Pumping
Association (ACPA) has created rules for cleaning pipes
with compressed air, that I believe need to be implemented
into the American Shotcrete Association (ASA)
safety guidelines. The shotcrete system is different
from placing boom type work when it comes to using
diverter valves and designated pumping stations. While
shotcrete locations typically change from day to day and
are not typically using a diverter valve, the rest of the
ACPA rules still apply.
Be extremely careful when using compressed air
to clean out the placing line.
1. Cleaning with air requires two trained people.
2. No person is allowed to be near the discharge
end of delivery line.
3. A dart catcher must be used and the outlet must
be controlled.
4. A proper blowout cap must be used.
5. The discharge end of the delivery line should
be in a position to permit easy discharge of
6. The dart or plug used must not be able to let
compressed air pass by and into the concrete.
7. No rubber hose can be cleaned with air unless
using an attachment specifically used for
clean-out into a designated box or mixer truck.
8. Work on the delivery line is allowed only after line
has been relieved of compressed air.
9. A good, reliable method of communication
between the operator and crew at the end of the
delivery line is needed.
10. All PPE must be worn when cleaning out the
delivery line, including gloves, safety goggles,
ear plugs, respirator, long sleeve shirt, work
boots, and vest.
22 Shotcrete | Spring 2020
Compressed air can only be used to clean out a
steel delivery line. It must never be used on rubber hose
as the hose whipping effect at the discharge end can
be extremely dangerous. When using compressed air,
one must be able to control and catch the object that
is used to clear the line. It is also very important to only
have trained people doing the cleanout. A blowout cap
must have the proper distance between the air inlet and
dump valve. The catcher must be properly sized to not
allow the dart to escape but allow the exiting concrete
to easily flow through it. A proper plug or dart must be
used to push concrete and it must not let air bypass
directly into the concrete. Allowing air to bypass can
create a blockage by separating the concrete.
When the shotcrete placement is finished, the trained
crew members will remove the rubber hose and connect
a dart catcher to the end of the steel line. Once this is
done, the operator will breach the line at the pump and
insert a rubber dart on the pump end of the line. The
operator and designated crew member must be able
to communicate, generally by radio. The pump operator
will begin to insert air into the delivery line and once
concrete begins to move, he will begin to control the
amount of air being added to the system. As the concrete
begins to move and clear the line, it will take less
pressure to move the concrete. The existing air in the
system will begin to decompress, accelerating the plug
or dart. It is important to feather the air into the system
and open the dump valve at the blowout cap to relieve
air and keep a slow and steady flow through the delivery
line. It is important to have a trained crew member communicate
with the operator when the dart is speeding
up, and how close the dart is from exiting the system to
keep a controlled blowout.
Cleaning the rubber hose can be done very easily
by using a garden hose with 50 psi of water pressure.
Once the rubber hose has been disconnected from the
steel delivery line, a clump of wet paper is forced into
the hose. A water cap is clamped onto the hose and a
standard water hose is hooked up and used to clear the
concrete from the hose. The hose is cleared when the
paper exits the other end of the hose.
The water washout is by far the safest and most practical
means to clean both the steel and rubber delivery
lines. By using water, one has a material that doesn’t
compress and have the potential for an explosive discharge
that has unfortunately become the norm in the
shotcrete industry.
Water cleanout only works when one has access
to a good water supply from a high flow water source
such as a fire hydrant, water buffalo, or water truck. At
the end of the shooting, the operator cleans the hopper
and valve by doing a quick washout of the pump and
inserts a plug or dart into the delivery line at the back of
the pump. They should then fill the hopper and, once
full, begin to pump water through the system until the
plug or dart is pumped out of the end of the system.
The water method is far safer than using compressed
air because it eliminates the potential for violent hose
whippings. Concrete pumps are capable of producing
Fig. 3: Shotcrete standpipe clamp and support
Fig. 4: Blowout cap Fig. 5: Dart catcher Spring 2020 | Shotcrete 23
much greater line pressure than even high-pressure air
compressors. However, the challenges are often the
availability of water and a place to put the water once
the system has been cleared.
Either one of these cleanout processes when properly
executed will decrease cleanup time, create a cleaner
steel and rubber system, and make priming the system
for the next day’s shooting much more successful. The
safety aspect is the most important consideration for
using proper techniques in the cleaning of the delivery
line. Using trained crew members and proven techniques
will keep everybody safe and give them the best
possible process so they can safely and efficiently place
shotcrete each and every day they go to work.
Brian Lywandowsky has been in the
concrete pumping business for 31 years. He
started out as a partner at Eagle Concrete
Pumping with his parents. The business was
small and started out with two ball valve
pea gravel pumps then steadily grew the
company into a fleet of five boom pumps
and four-line pumps. In 2007, Lywandowsky
sold Eagle Concrete Pumping to The Conco Companies
and went to work for Conco as an Area Manager in Redding,
CA. After seven years with Conco in Redding, Lywandowsky
made the move to the Bay Area and has worked his way to
now managing the Northern California pumping operation. In
addition to concrete pumping, Lywandowsky provides support
and leadership in the development and production of a
new Lightweight Cellular Concrete operation known as Con-
Foam along with his work in Conco’s shotcrete business.
Fig. 6: Steel line transitioning into rubber hose for final discharge Fig. 7: Shotcrete standpipe