2建90个实务重点（Build 90 practical priorities）.docVIP

2建90个实务重点（Build 90 practical priorities） The unit of inertia is: M4 2. Category of concrete structure environment: five categories 3. The relationship between the width of the staircase and the height H: 2H + B = 600-620mm 4. The most sensitive sound of human ears is 1000Hz. The steel plate specification method is long, bigger than 4M2 steel plate 6. Stainless steel is the alloy steel with chromium content above 12%. 7. Lime: CaO 8. Portland cement: P.O 9. The strength grade of cement is judged by the cement mortar test in 3 days and 28 days. The cement of slag cement is the best, the silicate cement is suitable for concrete projects that are high in early strength. 11. The use of inactive aggregate can prevent the concrete from being destroyed by alkali aggregates. 12. Slurry preferred medium sand, hollow rate less than 25% is called solid masonry. Marble is an alkaline metamorphic rock. The dry density of solid floor of coniferous trees is not lower than 0.32 g/cm2. The broadleaf is not less than 0.50 g/cm2. The DS3 level is used to measure the level of normal engineering. 16. Common theodolite DJ6. 15-30 layers of soil are not dug. 18. Excavating soil below ground water level should bring the water level down to below 500mm. 19. Before the foundation pit is finished, it should be carried out: measuring positioning, copying the line. During the construction of the rain period, the foundation pit should be taken: section excavation. 21. A layer of grey seam under the base of the brick is larger than 20mm. 22. Slag cement, large volume concrete of volcanic ash should be maintained for no less than 21 days. 23. The large-volume concrete pouring scheme is: comprehensive layering, segmented, bevelled stratification. 24. Basic characteristics of brick and stone: good compressive resistance, good integrity and low cost. The temperature difference between large and large concrete is controlled at 25 degrees. The large size is to be covered and watered in 12 hours. Large s