Using a backhoe is a lot like playing a very slow and boring video game. I have many more feet to go, so I'm sure I'll make the high score.There will most likely be no post next week.
Happy Thanksgiving!
Thursday, November 16, 2006
Finally the Footings
Thanksgiving is almost here and I am finally digging the trench for the foundation. Yesterday I dug the north end of the shop and got the hang of the backhoe controls. Here is a picture of the almost finished product.
Using a backhoe is a lot like playing a very slow and boring video game. I have many more feet to go, so I'm sure I'll make the high score.
There will most likely be no post next week.
Happy Thanksgiving!
Using a backhoe is a lot like playing a very slow and boring video game. I have many more feet to go, so I'm sure I'll make the high score.There will most likely be no post next week.
Happy Thanksgiving!
Thursday, November 09, 2006
The Blocks Passed
As stated in the previous post, I took the blocks to a testing lab to have them crushed. It was a marathon session, lasting from 3:00pm to almost 7:00pm at Smith Engineering in Roswell, New Mexico (no, I did not see any weather balloons). We ended up testing only the samples made from the native soil and the native soil fortified with portland cement.
This is a picture of the testing press with a sample in the pressing area. The press looked like it was built by IBM in the hay day of punch cards, but it is still capable of applying 200000 pounds of force.
The first test we performed was the Modulus of Rupture. This involves "breaking" a sample over two fulcrums (pipes) spaced a specific distance apart and applying the force over a third pipe equidistant between the first two. This is easier to see than say, so the look to the right for a picture of the jig I built for the test.
The press applies a force to the top pipe at a rate of 500 psi/minute until the block "breaks." I put the last in quotes because I was expecting the block to break in two, but the press gauge is so sensitive that it is capable of stopping the press as soon as the block weakens and all you get is a small crack in the base of the block as shown in the following photo. Although the lack of breaking meant a lot less cleanup, it was a bit anticlimactic
After finishing all of the Modulus of Rupture tests, we proceeded on to the compression tests. I did not take any photos of this test, but it is done in the same press and without the pipes. Again the press loads at 500 psi/ minute until the block fails. In this case failure come in the form of small cracks appearing all around the block.
For the Modulus of Rupture, the code requires the blocks to hold at least 50 psi. The Native soil blocks held a little more than double this. The code requires the blocks to hold a minimum of 300 psi in compression. Our blocks held a little over three times this amount. It looks like the shop should be strong.
This is a picture of the testing press with a sample in the pressing area. The press looked like it was built by IBM in the hay day of punch cards, but it is still capable of applying 200000 pounds of force.
The first test we performed was the Modulus of Rupture. This involves "breaking" a sample over two fulcrums (pipes) spaced a specific distance apart and applying the force over a third pipe equidistant between the first two. This is easier to see than say, so the look to the right for a picture of the jig I built for the test.
The press applies a force to the top pipe at a rate of 500 psi/minute until the block "breaks." I put the last in quotes because I was expecting the block to break in two, but the press gauge is so sensitive that it is capable of stopping the press as soon as the block weakens and all you get is a small crack in the base of the block as shown in the following photo. Although the lack of breaking meant a lot less cleanup, it was a bit anticlimactic
After finishing all of the Modulus of Rupture tests, we proceeded on to the compression tests. I did not take any photos of this test, but it is done in the same press and without the pipes. Again the press loads at 500 psi/ minute until the block fails. In this case failure come in the form of small cracks appearing all around the block.
For the Modulus of Rupture, the code requires the blocks to hold at least 50 psi. The Native soil blocks held a little more than double this. The code requires the blocks to hold a minimum of 300 psi in compression. Our blocks held a little over three times this amount. It looks like the shop should be strong.
Thursday, November 02, 2006
November
I don't know if the hook in the last post worked, but I am not able to make good on my promise of digging the foundation trench. Perhaps this failure to produce is fitting considering the coming elections.
Anyway, I have been busy on the project, but the dirt work did not get finished. One reason for this, is that I had to make blocks for testing. According to the New Mexico Earthen Building Materials Code, two tests must be performed on the blocks being used for building: the compressive strength test and the modulus of rupture. Each of these tests is to be performed on five randomly chosen blocks.
The soil on our building site is just on the edge of acceptability for compressed earth block, so am testing blocks made of the native soil and blocks made from a 50/50 mixture of the native soil and crusher fines (what is left over when quarries crush rock and then grade it out to piles of different size gravel). Each of these groups is again broken down into unstabalized blocks, which containing no portland cement, and stabilized blocks which contain 6-8% by volume portland cement (the latter can be used in contact with moisture; on this project they may end up being driveway pavers or sidewalks). So, if my math is correct, I have four different groups of block for each of the two tests. That ends up being 40 blocks.
Most of these I made at the end of the day on October 20th. The follow are pictures of the block press in action and some blocks on a pallet. I will take pictures of the tests, which are scheduled to take place tomorrow, and hopefully will have them available for posting next week (this time no promises).
Anyway, I have been busy on the project, but the dirt work did not get finished. One reason for this, is that I had to make blocks for testing. According to the New Mexico Earthen Building Materials Code, two tests must be performed on the blocks being used for building: the compressive strength test and the modulus of rupture. Each of these tests is to be performed on five randomly chosen blocks.
The soil on our building site is just on the edge of acceptability for compressed earth block, so am testing blocks made of the native soil and blocks made from a 50/50 mixture of the native soil and crusher fines (what is left over when quarries crush rock and then grade it out to piles of different size gravel). Each of these groups is again broken down into unstabalized blocks, which containing no portland cement, and stabilized blocks which contain 6-8% by volume portland cement (the latter can be used in contact with moisture; on this project they may end up being driveway pavers or sidewalks). So, if my math is correct, I have four different groups of block for each of the two tests. That ends up being 40 blocks.
Most of these I made at the end of the day on October 20th. The follow are pictures of the block press in action and some blocks on a pallet. I will take pictures of the tests, which are scheduled to take place tomorrow, and hopefully will have them available for posting next week (this time no promises).
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