Insulated concrete forms construction with Carmix in Northern California

We see a rise in the number of various applications of self loading concrete mixer Carmix among our clients in the USA.

Due to Covid impact on all industries and spheres of our life, most of the US and European producers of construction and in particular concrete machinery struggle to maintain adequate delivery times for their products, however with Carmix we always try to keep some new units in stock in USA for immediate delivery as well as the producer, Italian company Metalgalante SpA. is doing its best to keep sufficient stock of all necessary assembly parts of new units.

Don`t forget, you can always rent a self loading concrete mixer if you just want to try it or if you have a smaller project and it is not feasible to purchase the machine.

Just a few words about our client. This is a California based company, working in various states and is concentrated in the area of residential construction using Insulated concrete forms or ICF`s.

This is a technology that allows one to build a house of any design by constructing cast in place concrete walls that are sandwiched between two layers of insulation material. Compared to regular residential construction, this technology is quick, reliable and highly energy efficient as well as environmentally and health friendly.

ICF construction takes considerably less time to erect a building and is suitable for all various climate zones of the USA.

Apart from the outstanding qualities of concrete as an insulation material, this parameter is further enhanced by two layers of additional insulation of the ICF`s outer and inner walls.

Advantages of ICF technology

Owners benefits:

• strong walls
• disaster resistance and safety
• mold, rot, mildew, and insect resistance 
• Exceptional sound-insulation
• High energy efficiency

Builders benefits:

• Fast and easy construction
• flexibility
• light weight for easy shipping and erection
• Easy finishing of erected walls, both interior and exterior
• ability to meet higher energy code regulations with less complicated construction

We can see that this construction method is quite innovative, although it has been around for some time now. Carmix is a great addition to the ICF construction technology as it will allow to mix fresh concrete directly on site and pour it straight into the formwork. This should further simplify and accelerate the construction process.

For training purposes, the client wanted to pour around 20 cubic yards of 3000PSI concrete at his storage facility. This would give a good understanding of the whole process and allow the operator to familiarize himself with the Carmix operation process.

After we arrived at the site, we made sure that we had all we needed: adequate amount of aggregates, water supply, fuel for the machine.

While Carmix was being prepared for the first mix, concrete specialists were preparing forms and rebar for pouring.

Training process usually starts with a presentation of Carmix and a theoretical part where we show all major parts of Carmix, explain how everything works, how to operate the loading shovel, water system, weighting system etc. Also we pay particular attention to periodic maintenance of the machine so that future Carmix operators know how to keep the concrete mixer in good technical condition.

After the theoretical part we proceeded with setting up of the weighting system and uploading the necessary mix design. Client needed 3000 PSI concrete for pouring a durable surface at his yard. He plans to park heavy trucks and equipment at this spot.

After Carmix was ready we filled the on-board tanks with about 200 gallons of water and drove carmix up to the aggregate loading area.

Sand and gravel were dumped on the ground in separate piles and cement was delivered in 80lb bags on a pallet.

We were making about 4 cubic yards of concrete per batch, so everything was adjusted accordingly. The following recipe was used:

Per 4 Cubic Yards:

Water: 150 Gallons
Cement: 2,380 Lbs
Sand: 5,225 Lbs
Gravel: 7,077 Lbs

Due to the principle of Carmix operation, it is important to load aggregates in a certain sequence:

First we load water into the drum and mix it with cement, in this way cement is dissolved in water evenly and then we can proceed to loading sand. Gravel goes in last as it is the heaviest material and ensures that everything is mixed through thoroughly.

There is no need for separate mixing of concrete with carmix and by the time the last bucket of gravel is loaded into the drum and Carmix arrives at the pouring site, concrete is ready to use!

On this particular job, cement was delivered in 80lb bags and although it has some advantages to use concrete in such packaging, we usually prefer to use bulk bags of 1 or 1.5 tonnes per bag. This makes the whole process faster. Since cement is very sensitive to any kind of humidity, it is important to have it in a sealed packaging, whether it is smaller bags or bulk bags.

Carmix bucket is equipped with a knife that allows for easy discharge of cement bags into the bucket with one or 2 people.

The whole cycle of preparing 4 cubic yards of concrete took about 30-35 minutes since the operator was still getting used to the new machine and loading of cement took a bit longer than usual. Normally a full batch should take around 15-20 minutes to prepare.

One of the advantages of using Carmix for a pouring project is the fact that it is very mobile and compact, as well as equipped with various driving modes and rotating drum. It can be easily seen how much of an advantage this is compared to a standard mixer. Carmix was able to drive up directly to the pouring area and avoid the need for a concrete pump or any other equipment, thus reducing the cost of the project.

During that day, Carmix poured an area of about 1500 SF with a 4 inch depth.
Next the client plans to use carmix on one of the ICF construction projects around lake Tahoe, CA.

Mountainous areas pose extreme difficulty when dealing with concrete. Logistics of concrete delivery is very challenging and preparing concrete on site is expected to reduce total construction time by at least 40%.

If you want to know more about various self loading mixer applications, do not hesitate to contact one of our specialists to receive a detailed consultation and see how Carmix can benefit your particular project!