Concrete One Liner Notes
1. For quality control of Portland cement, the test essentially done is : setting time , soundness , tensile strength , consistency . 2. Under normal conditions using an ordinary cement, the period of removal of the form work, is : 7 days for beam soffits 14 days for bottom slabs of spans 4.6 m and more 21 days for bottom beams over 6 m spans 2 days for vertical sides of columns 3. W p and W f are the weights of a cylinder containing partially compacted and fully compacted concrete. If the compaction factor is 0.95, the workability of concrete is high . 4. For given water content, workability decreases if the concrete aggregates contain an excess of thin particles , flat particles , elongated particles , flaky paticles . 5. M10 grade of concrete approximates 1 : 3 : 6 mix . 6. For ensuring quality of concrete, use graded aggregates . 7. According to I.S. : 456, the number of grades of concrete mixes, is 7 .
