Rugged & Durable.
©Leading Edge Group Inc.
We have conducted numerous surveys and have analyzed soil maps and actual samples from all over the globe to determine what type of soil works best in our machine. Simply stated, over 85% of the world’s soil will work. We take regular soil right out of the ground, screen everything 1″ greater out, and use the rest to make our blocks.
The critical element that must be present, regardless of the overall makeup of the soil used, is clay. Even under extreme pressures, 100% silica sand and rock will not bind together to form a block. The makeup of an ideal soil would contain approximately 20-30% clay. However, we have successfully produced blocks from soil that contained 10-20% clay. While we can also work with higher clay contents all the way up to 90%, we sometimes have to add aggregate or rough, unwashed sand to that source to create a good, strong block.
What other materials / soil types may be used in its operation whilst maintaining structural integrity?
Most soils are made up of fine silt or fine clay, clay, aggregate, heavy aggregate, and rock or pebbles. Our machines are very forgiving in terms of what soil type works best. We have manufactured blocks in sandy soils, sticky clay soils and everything in between. So long as we have 20-30% clay content present, we can usually make a good block regardless of what the remaining soil (absent rocks) consists of.
Dry or windy conditions have no affect on the blocks. If the proposed construction site does not have any protection from the elements and it is located in a wet or rainy area, it will be necessary to stabilize the blocks in some manner. There are a number of ways to accomplish this. One is to mix approximately 5-8% Portland cement into the dry soil and then compress that cement infused soil into blocks. Those blocks would then need to be wetted for a period of 4-6 days to allow the cement to set. Those blocks would then hold up extremely well to moisture and rain. Another way to stabilize the blocks is to add and mix hydrated lime into the dry soil to a high ph level prior to compression. Once the lime-infused blocks are compressed, they can be laid directly into the wall. After the walls and structure are built, a lime wash or lime plaster can be applied similar to conventional stucco. Once this has been accomplished, these blocks will be impervious to moisture, rain, and erosion. Lime stabilization is usually less expensive than cement stabilization and doesn’t require that the blocks be turned over and handled again while wetting them. Cement stabilization takes less field knowledge than working with lime as you can simply use a percentage calculation as opposed to the testing required to adjust the ph level when using lime. You can also apply conventional cement stucco material over the soil-only blocks. While there are a number of waterproof paints and coverings that will adhere to our blocks, these products are usually quite expensive and not cost effective for most applications. Finally, if the walls will have a cover similar to a Barn pole roof, stucco finish or have a bona fide roof system in place – you wouldn’t need to do anything to the soil only blocks. They would hold up quite well in a protective environment.
History shows us that adobe and soil buildings have endured for hundreds, if not thousands, of years. For blocks that are not stabilized, you will need to have them protected from the elements if you are operating in wet conditions. For areas where temperatures can reach 115 degrees or higher in a dry, arid desert for most of the year, blocks can be placed right out in the elements with very little degradation. Even if the top layer becomes worn due to an unseasonable rain, you can simple replace the damaged blocks and add a new layer of blocks. If you stabilize the blocks via either method described, they will unquestionably last a very, very long time.
The equipment requires the same type of regular maintenance that a front end loader or bulldozer would normally require. It has several grease fittings that need to be hit a couple of times a day and the various temperature and pressure gauges need to be monitored while operating. Each model requires about 45 minutes per day to service and maintain. We have units currently operating in the field that have produced over one (1) million blocks and are still operating with most of the original components still in place and functioning as intended.
All of our units use approximately 1.5 gallon of diesel per hour of operation.
Both machines can be containerized into international shipping containers. The Series 960 unit weighs approximately 9,800 lbs. and is 8.33 ft. wide by 16.5 ft long by 8 ft. high. The Series 480 machine weighs 5,600 lbs. and is 7.38 ft. wide by 13.67 ft. long by 6.83 ft. high. Both units can be towed behind a heavy duty pickup or HMWWV. The equipment can be licensed for towing and legal highway speed limits can be attained with no problems.
The units come fitted with military-style lifting hooks and can be lifted via a sling with a Chinook or Black Hawk helicopter.
You would normally need a crew of around 4 – 5 handling the blocks as they come off the machine. The large machine (Series 960) produces up to 960 blocks per hour or one every 3.5 seconds. The mid-sized unit (Series 480) is rated to produce up to 480 blocks per hour or one every 8 seconds. Working two men on each side of the conveyor and alternating the output keeps things moving without stressing the block handlers too much. A standard pallet holds 96 blocks and the standard size blocks are 14″ x 10″ x 3.5″ weighing 36-38 lbs each. After the machine is started, it operates automatically and will continue to produce blocks so long as the hopper stays full of soil. You may pause the machines at any time but you cannot slow them down to produce fewer blocks per hour – they are either in a full operating mode or in paused or stopped mode.
We can produce approximately fifty (50) 14′ x 10′ x 3.5′ compressed blocks with one (1) cubic yard of soil. The capacity of a standard sized dump truck is approximately 20 cubic yards.
Follow the formula below:
- For a 10″ thick wall: = 2.7 blocks per square foot of wall space.
- For a 14″ thick wall: = 3.4 blocks per square foot of wall space. Example: 10 ft. length x 8 ft. height, 10″ wall = 80 sq. ft. x 2.7 = 216 blocks.
NOTE: Do not deduct for the area to be taken up by windows or doors.
We use the exact same soil for the slurry as is used for the blocks. The soil is screened down to remove any rocks or pebbles and we then make a wet, thin, pancake batter-like mixture. This slurry can be mixed in a wheelbarrow or motar mixer. It is important to remember to have the water first and add soil to it to create the desired consistency. The slurry is applied via a coffee can or similar means directly onto the lower block course and the blocks are placed on top just like you would with conventional bricks. The slurry creates a homogeneous bond between the two block layers much like pressing two bars of soap together in a shower. On a hot day in central Texas, the blocks will bond together in just a few minutes, requiring a hammer and chisel to dislodge them.
It is impossible to make blocks in rain unless you have moved the soil and the machine into a warehouse or a covered area. The blocks can be produced and laid into a wall in cold weather as long as the mortar mix is not frozen. Heat has no effect on the blocks or the mortar other than to dry things faster. If the soil is extremely dry (as found at Fort Irwin, CA), a light fogging of the soil with water will produce the desired moisture content. Most soil has adequate moisture and doesn’t require additional moisture. We have operated the equipment in 124+ degree heat and have had no problems with the equipment or the blocks.
Adobe construction is an accepted and approved method of construction throughout most of the Southwestern areas of the US. Our compressed soil blocks exceed (usually by 3-4 times) the building strength of material standards for non-fired masonry construction in the United States. Our soil blocks have exceeded, in all cases, the Uniform Building Code (UBC), the Southern Building Code, the HUD Standards, the Farmers Home Administration Standards, the Veterans Administration Standards, the FHA Building Material and Construction Standards, and The International Building Code (IBC). The IBC spells out the specific guidelines that should be adhered to throughout the entire country. Another good source of information is the New Mexico Earthen Building Code which regulates the construction of new buildings made of adobe, rammed earth, and compressed earthen blocks. Keep in mind that these blocks are load bearing – not filler blocks. The minimum standards for adobe construction as per the Uniform Building Code is: COMPRESSIVE STRENGTH 300 psi Minimum Standard LEGI Compressed Soil Only Blocks 1,000 – 1,500 psi LEGI Cement / Lime Stabilized Blocks 2,500 – 3,900 psi MODULUS OF RUPTURE 50 psi Minimum Standard LEGI Compressed Soil Only Blocks 70 – 140 psi LEGI Cement / Lime Stabilized Blocks 250 – 600 psi
All of our equipment is available on our GSA Federal Supply Schedule. The contract number is: GS-07F-0320U. The pricing specifics relating to each model can be found on the CONTRACT VEHICLES Tab found on the Homepage of this website. In addition, we also offer equipment leasing programs.