(November 15th '11)
The results of an environmental exposure test. The two samples - one containing 5% Lime and the other a similar ratio of cow shit - have been left out in the elements for several months and have reacted quite differently.
The nearest sample contains the cow shit and although it has ruptured under pressure, the actual sample remained intact throughout the exposure.
The rear sample, containing Lime, has retained more strength but is showing signs of surface crumbling due to freeze-thaw cycles!
(July 27th '11)
2.56 MPa!
My first 'official' crush test done by Levelton's geotechnical laboratory, here in Victoria. I will need to show that I can achieve 2 MPa or greater with my entire batch of 4 samples, but this is a very exciting development and the highest strength achieved so far. Another six samples are being tested and I should be able to post the results soon.
(June 17th '11)
The 'Ball Dop Test' 1. A handful of my rammed earth material pressed into a ball about the size of an orange ready to be dropped to test it for correct moisture content.
(June 17th '11)
The 'Ball Drop Test' 2. Having been dropped from about a meter onto a hard surface (concrete floor) the ball has shattered extensively, but parts remain stuck together. My research suggests that this is a good indication. If it completely shattered it would require more water. If it remained in a few larger pieces (or didn't shatter at all) it would be too wet.
(June 11th '11)
Mark 4b compression mold. A slight modification to the previous model incorporating the three pipe clamps. The pvc around the bolts securing the flanges isn't strong enough under pressure but the clamps should prevent it from stretching.
The two lower clamps are cut at the flanges and secured to them via the bolts holding the flanges to the cylinder, thereby allowing the flanges to be seperated when removing samples.
The upper clamp is slipped over the mold and tightened manually.
(June 1st '11)
The latest (mark 4) version of the compression mold which I hope will address the minor problems that affected all of the previous versions!
Although not visible in these photos, the pvc pipe is slit vertically along one side in line with the metal flanges. The flanges are bolted together to form a rigid cylinder but can be flexed apart in order to remove the samples.
(March 26th '11)
A 20th scale model of the workshop, cut away to show details of the various elements of the building.
(March 25th '11)
Success! We have achieved our first rammed earth test result of 2 MegaPascals. Based on what we have learned recently, I believe we can do even better!
The break-through rammed earth sample immediately after it failed at exactly 2 MPa! Faint cracks can be seen running vertically up the sample.
More trials and testing to do in the belief that this can be further improved upon.
(February 13th '11)
Ben Macklin using my simple but effective home-made weigh-scale, to measure the clay and aggregates for the rammed earth test samples. Litres of water (1 lt = 1 Kg) are used as the reference weight in the blue bucket.
(February 13th '11)
After a bit of a 'time-out' resulting from my failure to acheive the necessary compressive strength in my earlier testing, I am back at it - with the help of Ben Macklin. This is our first sample, taken straight out of the mold after compaction. This is a major step in the right direction as all my previous samples were too weak to be removed immediately!
(October 4th '10)
The crush test result for a 3-inch sample of clay from my site (photo below). This figure represents about 4 MPa which is double the compressive strength I need for my foundation wall!
(October 4th '10)
A 3-inch sample of clay, just after it failed, resulting in the compressive strength reading above!
(July 14th '10)
An interesting perspective. Using a close-up of a model car in the foreground to create a sense of realism in the photo of the workshop model!
(June 10th '09)
The current design. hopefully the final one!
(April 6th '10)
My new 'toy' - a Makita Chain Mortiser. Although quite expensive, this tool should make the construction of the joints in the timber frame much quicker and easier.
(June '09) the site, looking north towards the house.
(February 13th '10)
Two samples of lime plaster. The sample of the left is composed of 25% Lime putty and 75% sand. The sample on the left has about 10% brick dust added to test the pozzolanic effect (if any). If the brick dust works it should cause the plaster to set faster and harder than the other sample.
(postscript: the brick dust didn't seem to make much difference in the speed or hardness of the set!)
(February 13th '10)
Plaster of Paris end cap on the bottom of a compression sample. The caps, which will go on either end of the samples, are intended to create an even, level surface when crushing the samples in the compression tester.
The black plastic mold has been slit all around the edge so that the samples can be removed easily once dry, and was sprayed with lubricant to further prevent binding.
(February 3rd '10)
Three branches harvested from five old and diseased chestnuts that were taken down along Cook Street in Victoria.
It feels good to be able to recycle timber from these noble trees in the building. Two of the branches will be used as central posts, supporting the roof in the main workshop area. I hope to turn the third branch into a book-matched table-top eventually.
(February 3rd '10)
The three chestnut branches protected from the rain. In due course the bark will be stripped off to aid in the drying process.
(January 17th '10)
The components of my prototype compression testing mold.
(January 17th '10)
My home-made compression testing mold. Mark 1. The hinged halves can be bolted together, and then released to allow the 6-inch by 12-inch samples to be removed easily.
(postscript: although a sound design in principle, the piano hinge was not strong enough to withstand the pressures generated by ramming and eventually tore apart.)
(January 17th '10)
The curent design. The floor plan remains similar to the original version, but the roof line has been dramatically altered and improved thanks to John Gower. (gowerdesigngroup.com)
(August 29th '09)
Although not completely dry yet, this picture gives an indication of the amount of shrinkage that can be expected from our native soil. By my calculation it is about 7 - 8 percent.
(August 29th '09)
Sedimentation test. After about one month the soil has (mostly) settled out of suspension and it can be seen that there is about 75% clay (on top) and 25% silt with very little sand or larger aggregates.
(August 23th '09)
My neighbour, Tony, scraping off the top soil to expose the 'native soil' (clay-rich earth) in a pit just below the building site. From this pit we hope to source the earth that will be used, in combination with lime and aggregates, to make the rammed-earth foundation wall and the earthen plaster.
(July 30th '09)
Loading a thick mix of clay soil into a container for a shrinkage test.
(July 30th '09)
Once filled with the sample soil, the container is left to dry. This test had to be re-done because the sample split along the visible stripe making subsequent measurements of shrinkage inaccurate.
(July 29th '09)
Breaking ground... our neighbour, Tony Couto, digs a series of holes around the proposed foundation to take soil samples. We want to see if we can use the underlying clay for our rammed earth stem wall and the earthen plaster on the walls.
(July 29th '09)
A geotechnical engineer from C. N. Ryzuk and associates supervises the digging in preparation for taking soil samples for testing. I do not recommend this company as I believe they tried to over-charge me and misled me.
(July 29th '09)
Unfortunately, the 'native' underlying clay at my site may be too deep for me to use, as I would have to dig much deeper than my intented trench depth (24 inches) in order to access it.
(July 13th '09)
Two curious visitors to the building site this morning, unfortunately they then went on to nibble the honeysuckle!
(July '09)
Construction of the 30 mesh screen used to sieve the lime putty after it has been slaked. two rings of steel were riveted together with the mesh in-between.
(July '09)
My home-made tools for screening the lime putty. the cut-away detergent container is ideal for scooping the putty out of the bath in which it is slaked. the screen is supported by bars so the putty can be pushed through with the trowel.
(July '09)
How the putty screen works - 1. painting it with primer seems to have been ineffective!
(July '09)
How the putty screen works - 2. the pins around the edge support the screen in the top of the burn barrel. The edges of the trowel were ground into curves to help squeeze the putty through the screen.
(June '09)
Slaking quicklime! Ben Scott carefully adds the quicklime to the water as he shows me how to make lime putty. doing it under a tree is not recommended, as leaves and bug can end up in your putty!
(June '09)
Heat rising! Ben supervises as I use a rake to thoroughly mix the quicklime with the water. steam rising from the bath illustrates the amount of heat generated by the chemical reaction of slaking, so protective gear is essential!
(June '09)
What the building might look like from our neighbour's deck! (postscript - this was an early design that has since changed. See images above)
(June '09)
The view from the roof of the main house showing beaverdale creek along the eastern side of the property.