Jan 30

United Equipment Sales Expands Its Operations!

Moving into a new home is considered to be a life event, but when you move 40 years of business, a warehouse and its entire inventory, it takes a move to an entire new level! So when we decided to move to a new and larger facility, we knew that it would temporarily disrupt our business so we chose a quieter period. We ended up not only expanding our working space, but also upgrading some of our office equipment, software that was in serious need of upgrade. More space means more machines, more business, more custom repair which have kept us busy, busy, busy!  And that’s a good thing!

So, we have put together a short video tour of our new 13,000 sq ft facility. You’ll get to meet Dick Hibbard, a.k.a. Mr. Concrete Pump! See our certified mechanics take concrete pumps in dire need of TLC and bring them back to life!

Our PARTS SHOP has everything you need!

Parts Shop

Clamps, couplings, reducers, gaskets, nozzles, elbows, adapters, welded groove ends, hoses of all sizes and much more…

 

Rich runs the repair Shop

 

 

 

 

 

Talk to Rich in our Repair Services if your pumps or hoses need to be repaired or have some custom work done.

Our staff is here to serve you and your business.

Meet The Team!

Our company mascot and official greeter couldn’t make it for the group photo, so here she is in her command post:

Snowbella

 If you are in the area, come by and visit us, we would love to see you!
Or call us at: (503)283-2105

 

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Jan 21

What is Polyurethane Concrete Raising?

Difference between Mudjacking and Polyurethane Concrete Raising

Also called foam lifting, polyurethane for concrete raising has been in practice for about 20 years. However, the price of the equipment and polyurethane material made it way too expensive for private contractors to adopt and replace traditional mudjacking. It has mostly been used by the Department of Transportation to raise streets and highway roads. Well, until now! What changed?

1.The equipment:
Today, smaller and affordable basic trailer units can be bought for under $50K that contain everything needed to do the job. They can also be pulled by a simple pickup truck that can carry the equivalent of 5 cubic yards of material. The polyurethane can be shipped and stored in 55 gallon drums.

2.The material:
This used to be protected under a patent. By mixing a two-part polyurethane, a reaction is created and the material expands to fill voids and raise concrete slabs. On-demand instead of batched. The average cost of Polyurethane material at $153.00 per cubic yard.

3. The selection:
There are several types of foam depending on the job requirements:
Lightweight and fast reactive
High density foam (for heavy slabs on highways)
Single component polyurethane to bind and stabilize loose soil
(http://www.mudpumps.com/materials/)

Mudjacking Versus Polyurethane concrete raising

Both techniques are used for similar projects with settled concrete: garage floors, driveways, entry, porches, sidewalks, basement floors, pool decks etc.
Both achieve the same results and are cost effective alternative to pouring new concrete but the process is a bit different.

Mudjacking equipment:
As a minimum you will need a paddle mixer, a truck that can carry 5 cubic yards of material, a front end loader, a yard to store bulk materials!

Mudjacking material:
Lots of dirt! Pumping 100 lbs per cubic foot of sand mixed with Portland cement under the settled slab. Foam, on the other hand, weighs about 2 lbs per cubic foot! The cost of mudjacking material is less than $20.00 per cubic yard. So it is quite cheap.

Mudjacking, doing the work:
Mudjacking involves heavy work like shoveling material into a mixer, drilling lots of 1” holes and moving a pump around the job site.

Compared to mudjacking, polyurethane concrete raising is pretty light work, much less physically demanding. For one, no dirt to haul, one person can handle the job. Using a pickup truck you can move the trailer unit anywhere on the site, as close as you need to be, drill a few 5/8” holes, inject the liquid foam in them. 5/8” holes are very tiny compared to having to drill many 1” holes when mudjacking. So there is little patching to do.  The job is completed in record time and the surface is immediately ready to be used. In less than 15 seconds, the liquid turns into foam and reach its final volume. Once cured, it will never lose its density! You can cover a much larger area in less time than with mudjacking because of the material can easily be delivered in any area and cures so quickly.

So if you are tired of hauling dirt, heavy physical labor, ready for something new and cleaner, you might want to look into foam raising. It is here to stay and has a very promising future.

And, if you have mastered the art of mudjacking and are in need of a good concrete pump, check out our mudjacking pumps specials.
Or give us a call at: (503)283-2105

Reference Material:

Mudjacking 101: How to repair broken concrete
http://www.mudpumps.com/concrete-lifting-options-the-pros-the-cons/

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Jan 04

Minimize Rebounding in Shotcrete

Shotcrete, a.k.a gunite, is a wet mix technique that produces a high velocity cone-shaped spray pattern via pneumatic mechanism onto a horizontal or vertical surface. Increase the air from the shotcrete nozzle to increase the velocity and the compaction of the particles and produce a denser concrete. Shotcrete uses either aggregates or mortar.

When to use shotcrete?
When you need to apply concrete vertically but do not want to deal with formwork and poured in concrete. Shotcrete works best for covering or repairing curved surfaces like swimming pools, bridges, tunnels, dams, slope reinforcement…

Strength of Shotcrete
Shotcrete uses a wet mix so the water/concrete ratio is very important and controlled by the nozzle man. It needs to be low (under 0.5) to obtain a denser and water-resistant mix.  This will also help reduce shrinkage and lower permeability in the finished product.

What is rebound?
One of the problems with shotcrete is the loss of material from concrete ricochets off the target surface due to the high velocity of the spray. This causes having to use more concrete, longer application times etc. The result can be vastly different when it comes to the properties of the in-placed concrete mix. If you use steel fibers as a distribution solution, the problem is even more problematic than with aggregates. According to Austin and Robins (1995), aggregates rebound is about 20-30% whereas with steel fibers, rebounding can reach 35-78% (Morgan et al., 1987; Banthia et al., 1992) with dry-mix shotcrete. With such high rebound, compaction is reduced and the concrete strength ends up greatly compromised.  The rebound of non-adhering material during a gunite operation (using a dry process) is greater than during a shotcrete job (wet process) because gunite requires a much larger air compressor. On a gunite job, the rebound material can be reused, whereas, on a shotcrete job, the non-adhering material is wasted. Removing it is time consuming, slows progress and can be costly. So choosing the right technique for the job is essential.

Thick or thin applications?
It turns out that the percentage of loss is affected by the thickness of the layer sprayed. In other words, the thinner the layer of shotcrete, the larger the percentage loss. The highest amount of rebound happens in the first spray on concrete. With subsequent coats, rebound diminishes. Another factor affecting the rate of rebound is aggregate density. A lower density will result in lower rebound rate.

Some solutions
Some polymer additives (Etonis) or modified starches can improve the adhesion and flow properties of concrete and reduce crack formation.

What pump is best for your job?
 If you are not sure what concrete pump is best for your next job, call Dick Hibbard at (503) 283-2105. With over 40 years experience in all things concrete, no question is too simple or too complex for him!

Some great pumps he recommends are:

Schwing WP 1000 concrete pump

A Schwing Wp-1000X

 

 

 

 

 

A Reed B-50 or C50Hp

Reed B50 and C50HP concrete pumps

 

 

 

 

 

 

Check all the great deals he has on Mayco, Schwing, Olin, Reed and Putzmeister used shotcrete pumps on United Equipment Sale’s website:
If you you need a gunite machine, check our site for our latest great deals.

Reference material
Parametric Studies on Fiber Rebound in Dry-Mix Shotcrete
The American Shotcrete Association
Polymer modification of shotcrete

 

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