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Concrete Lab Report

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Engineering B45 Concrete Lab Report
Introduction: Concrete is a mixture of sand and rock or similar inert material (aggregates) held together by a cementing material. Usually the cementing material is Portland cement, but sometimes binders such as asphalt or gypsum are used, in which case the concrete may be called asphaltic concrete or gypsum concrete.
Properties of concrete are governed not only by the properties of its ingredients (cement, water, sand, and coarse aggregate) but also, to a great extent, by the relative proportions of these ingredients. The proportions must be so selected as to produce a concrete mixture of desired workability, strength, durability, and economy.
The most common aggregates are gravel and crushed stone, …show more content…

You may not need to add the full amount of water calculated. Be sure to use the gloves provided as you mix your concrete. When adding the water note the concrete’s cohesiveness – whether the concrete tends to hang together well or whether it tends to crumble readily – and the troweling workability – if the concrete works smoothly and with little effort when using a trowel. Continue to add water until you have a desirable consistency.
6. Perform the slump test. Fill the slump mold 1/3 full and tamp with the tamping rod 25 times; add more concrete until 2/3 full and tamp an additional 25 times; fill completely, tamp 25 times and then top off. Do not tamp more than 25 times. Measure the height of the concrete after removing the slump mold. The slump is 12” (the height of the mold) minus the height of the concrete after removal of the mold. The greater the slump usually means the greater the workability. Your slump should be about 2 inches.
7. Be sure to measure and record the temperature of the concrete and the outside temperature.
8. Fill the molds, tamp 25 times, top off, and cover with a plastic bag to setup.
9. After a day or two, cut off the mold. Note any cracking or pores in the test samples. Put the concrete samples in a bucket, spray the concrete with water, and cover the bucket tightly with plastic.
10. On the designated “concrete crush lab day,” perform the compression test according to ASTM C39.
Questions to be addressed in the

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