Block configuration 8x12x24 inches. R32, Weight 45 lbs.

Block configuration 8x10x24 inches. R27, Weight 37 lbs.

Block configuration 8x8x24 inches. R21.6, Weight 30 lbs.

Purpose
A more substainable substitute for reinforced concrete block is needed for the construction industry, one that includes insulation of the highest R-value per inch, on delivery to the site. It must provided for reinforcing, for adaptability to various configurations of the plans and elevations, and be easy to install without complicated equipment or proceedures. It must be waterproof for long term duration, vermon-proof, fireproof, and eathquake resistant where needed. It must be able to accomodate electrical and small-scale mechanical runs inside the wall near the innerface. It must have the option for various internal thermal mass on the inside layer to meet the thermal design systems of each specific building. Further, the block should be made of as much recycled and renewable materials as possible while satisfying the overall purpose.
Description of the parts
The insulative core is to be made of a matrix of perlite or pumice, bonded together and to the outer and inner wall substrates with a bonding agent (acrylic?) and fibres as reinforcing. This matrix should be capable of transfering some shear, compressive, and tensile loads between and along the edges (inn all directions.) Void trenches cast in this matrix can accommodate reinforced concrete superstructure and small wires and pipes for mechanical purposes. This material, along with the substrates should be cuttable with a diamond blade saw.
The outer and inner wall substrates should be made of a waterproof and fire-resistant composite board, currently available on the market. Its thickness could vary in response to desires for thermal mass, strength, weight, etc. The board should be of a high recycled content, and provide a good surface for bonding a stucco finish or allow attachments such as brick or veneer ties by screws without splitting.
Void Locatons and Sizes
As these are determined by the configuration of the mold, which can vary to acommodate different requirements within a project. Special voids should be able to be cut with a diamond hole saw or extended speedbore. Of course the less matrix, the less insulation. At present our plan is to add reinforcing voids diagonally opposite each other in the block to use the maximum thinkness of the wall for structure, creating the maximum moment arm for compression and tension resistance.
Assembly
It is assumed that the first course would be laid in cementous mortar in order to establish a level beginning for the layout. Above that, the block would be secured with a bead of adhesive on each side of the wall, and tapped down with a rubber mallet. Connective framing can be fastened to the openings by long screws into the matrix either on the surface or inserted between the substrates. Horizontal poured reinforcing in block construction as bond beams is usually spaced every four feet, so if the block were 2'8" long by 1'4" high, the horizontals poured ties could be every other course at 2'-8" increments. or every third course at 4' increments. A bondbeam at the roof level could extend the width of the wall, if it is above the insulated space. Beam pockets at floor levels could extend halfway into the wall on a smaller horizontal pad.

Block configuration 8x8x16 inches. R21.6, Weight 20 lbs.

The concrete frame shown with bearing pads for floor structure. Loads are carried to both inner and outer vertical columns. Various configuration of the pad portion can respond to load requirements such a beam carrying sigificant load or a deeper beam.

The matrix
Perlite has been chosen for the bulk of the matrix material because of its history of use as an insulator in block cores, and other insulating uses in construction. Also it is lightweight, fireproof, vermon-proof, and a good sound insulator. It is made from natural volcanic rock by heating, which drives off the water content, exploding the rock like popcorn. It is widely avaiable throught the world, and inexpensive. It's thermal conductivity is between .27 and .41 BTu x in/h x sqft x degreeF. It is only very slightly soluable in water. It's fusion point is above 2,300 degrees F. For more information on perlite go to www.perlite.net
Test performed in Winter '06
Nine small casting of various mixes were made. Initially it was thought that a slurry of cement, very fine aggregates, acrylic bonding agent, and alkali-resistant glass fibres would bond the perlite into a firm mass. The amount of slurry was an isuue; too much would fill the spaces between the perlite sufficiently to allow thermal bypass around the perlite, and also add too much weight to the matrix. The first attempts were too dense. The next castings were made with less slurry, but were basically too crumbly. Edge particles, especially corners, were easy to break off manually. At this point it seemed that perhaps the cement and aggreagates were perhaps not necessary. They were definitely adding too much weight. Keeping in mind that the more air broken into cells the better, it seemed that the test should start with the minimum of components, adding new one only when test showed that something else would be required. Also a problem with the first 9 tests was that with so many variables, it was hard to know which interactions were pejorative or unecessary, or possibly redundant, and the proportions of the mixture had too many options with no evidence of optimization paramteres.
Tests performed in Fall '06
A mixture of one part liquid acrylicbonding agent to 3 parts perlite (by volume) created a marginally saturated material which when pressed into the form and cured for a week, created a firm and compact mass. The sample was small and as acrylics cure by exposure to air, the larger the mass, the slower would be the cure. The bonding agent was Silpro C-21 which contains a large amount of water compared, for example, to artists mediums such as Liqutex. The exposed surface can be readily disrupted with a finger nail, and so is not hard enough to survive handling in the field, both in delivery and assembly. However it is possible to pour a strong, more tightly bonded mix in the bottom half inch and top half inch, which are the only surfaces exposed to handling disruptions.
The next 2 tests were as follows: (a)1 part portland cement ( it is expected by some portion of the cement can be replaced with fly ash in actual production), 6 parts perlite, and 2 parts acrylic bonding agent; (b) 1 part portland cement, 6 parts perlite, and 2 parts water. There is some indication that the water alone might be sufficient were this mix to be used as a top and bottom layer of the matrix. After curing, both samples were durable and lightweight ( approximately 33.5 lbs./ft3), the weight of the bonding agent being negligible. However, when cast into the fibreboard sides, the cement alone might not bond adequately to the fibreboard which would be important if the fibreboard is to resist shear forces.
Block sizes
A solid block 8x8x16 inches would weigh 19.8 lbs, and one 12x12x16 would weigh 60 lbs. The size of the block should be determined by the ability of one person being able to lift it into place. The modular sizes of standard concrete block may not be relevant in considering the sizes of these components, but bar spacing and insulation levels desired may influence the configuration, and thus the various sizes. In terms of compatibilty with other systems, some increment of 8" ( 8-16-24 ) is probably wise. Additionally the maufactured avaiable sizes of fibreboard fit this modular.
Tests performed in Winter' 07
Larger blocks of now refined mixtures were cast, but none of the tests proved capable of bonding to the fibre board which had been primed with a bonding agent. It would seem simpler to spray a harder coat of material to the front and back surfaces to create the hard surface for attachment or finishing.
The introduction of cellulose fibre and the elimination of the portland cement in one test casting have proved to be a progressive step forward. While slightly fragile to scratching at the surface, the block holds together well under compression. One additional idea to speed curing of the acrylic bonding agent would be to have metal forms coated with a surface to which the bonding agent does not readily adhere, with small holes over the entire surface to allow air to pass through the forms until the casting is adequately cured to unmold it.
Ideally a differential mix from edge to center would solve several problems, although the machinery to test this would be more complicated and expensive; however, such a method could be tested by approximation, by making 2 different mixes, and combining the differentially from edge to center and back to the other edge. This will be the basis for the next tests, along with forms that include voids for reinforced concrete fills, and at the scale of actual potential product. continued next page

The matrix without the surface substrates. Channels for rebars shown as light pink, and channels for mechanicals shown as dark pink. The mechanical channels can be customized by adding tubular pieces to the surface of casting forms and by inserting treated paper tubes through the forms.

The matrix cut to create a poured bearing pad for a floor joist or beam. The position of this pad allows half the lengths of the block to located the bearing point while maximizing the insulation between the pad and the outside surface. The left edge of the top cut is angled to allow a continuous bent rebar to transfer loads along the diagonal cut to the outside vertical poured structure.