The World of Civil Engineering

Compressive strength test of concrete -step by step procedure Apparatus the compressive testing machine should be reliable, of sufficient capacity and able to apply the load at approx 140 kg/ SQ cm per minute. The permitted error should be limited to maximum +/- 2 % of maximum load. Age at test compressive strength testing shall be done at definite age the most common being 7,15 and 28 days. In case of urgency to calculate strength, the test may be done after 24 hours (+ / – 1/2 hours) and 72 hours ( + / – 2 hours). It is to be noted that the age of the specimen is calculated from the time of adding water to concrete ingredient. Number of Specimens — At least three specimens, preferably from different batches, shall be made for testing for each selected age. procedure for determining compressive strength test of concrete 1.The test specimen shall be immediately removed and tested while it is in wet condition. Excess water shall be wiped off. If test specimen is r...

Field tests on cement

November 20, 2016

Field tests on cement Following field test can be done on cement for quality checks. However, if cement satisfies the field tests requirements, does not really indicate that cement is of good quality. This field tests can be performed for quality check purposes for the using cement for less important works such as plastering, block work OR temporary works. For major works such as substructure and superstructure (Footing, columns, slab and beams etc), cement must be tested with laboratory test such as Fineness, setting time, compressive strength, soundness etc. Quick and easy field tests on cement 1. Check manufacturing date printed on the cement bag. The cement should be used within one month from the date of manufacture. 2. Take a pinch of cement and gently press between the fingers. It should give smooth and nor coarser feeling. 3. Take a bucket full of water and through a hand full of cement in the bucket. The cement sh...

Field tests to determine the soil texture

November 20, 2016

Field tests to determine the soil texture Moist Ball Test – Compress *moist soil by squeezing it in your hand. If the soil holds together (i.e. forms a ball) when your hand is opened, then test the strength of the ball by tossing it from hand to hand. The more durable the ball, the more clay is in the soil. Shine Test – Roll *moist soil into a ball and rub once or twice against a hard, smooth object such as a knife blade or a thumbnail. A shine on the rubbed surface indicates clay in the soil. The more it shines, the more clay is in the soil. Ribbon Test – Roll *moist soil into a long thin shape and then squeeze out between the thumb and forefinger to form the longest and thinnest ribbon possible. The longer the ribbon, the more clay is in the soil. Soils with high silt content will tend to flake rather than ribbon. Feel Test – Rub *moist to wet soil between the thumb and fingers to assess the percentage of sand (Sand feels gritty). Silt feels smooth and sil...