#9

This week I am working in the lab. The engineer gave his request for the samples that he wanted test performed on for the samples that I drilled last week. I worked under the lab manager Paul. He is very knowledgeable and patient when showing me how to perform each test. I performed moisture and density tests on the ring samples. This is basically weighing the ring samples and then cooking out the moisture. I also performed a grain size analyses. The soil sample is placed into a stack of sieves that start larger in size and then become smaller toward the base. The stack of sieves is then placed in a shaker machine that shakes the sieves for about ten minutes. The sieves are then separated and weighed to determine the grain size of the soil.

In addition to performing lab tests on the soil samples that I drilled, I was also taught how to break concrete cylinders. PSI’s work load consists in a large part in concrete sampling, and testing. Each jobsite that pours concrete has to have a PSI technician sample concrete every 50 yards.  Once the samples are brought back to the lab they get broken 7, 28, and possible 56 days after the date cast. I performed the breaks today. The concrete cylinders are placed in a compression machine that applies a gradual amount of psi until the cylinder breaks. The psi is then recorded including how the cylinder broke. I really enjoyed working in the lab. I look forward to more days in the lab, and learning more lab tests.