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There are four phases of projectmanagement which are required to manageprojects efficiently on quality, time and costs. Defining and organizing the project: Defining project is the first step in the projectmanagement process.
WHAT IS PROJECTMANAGEMENT? Tweet A project is a set of interrelated activities, usually involving a group of people working together toward a common goal or objective over a period of time. Not surprisingly, projectmanagement requires strong organizational, budgeting, staffing, controlling, and communication skills.
The size of movement depends upon the change in temperature and the coefficient of thermal expansion o f concrete. The size of movement depends upon the change in temperature and the coefficient of thermal expansion o f concrete.
Cracks in concrete beams due to increased shear stress 2. Cracks in concrete beams due to corrosion or insufficient concrete cover 3. Cracks parallel to main steel in case of corrosion in beams 4.
When the formwork is erected the concrete can be poured. When the concrete has reached the required strength the formwork can be poured. If the steel had been placed too close to the surface and the concrete had been poured then over time the steel may become exposed to moisture and corrosion will commence.
Use of Precast Concrete in frames: There are two main types of precast building frame. Use of Precast Concrete for Floors: Each year the industry makes about 5 million square meters of precast floor slabs. Structural frames are mainly used for offices, car parks and retail developments.
Upon wetting, concrete tends to expand. These moisture-induced volume changes are a characteristic of concrete. If the shrinkage of concrete could take place without any restraint, the concrete would not crack.
The benefits of using steel fibres in concrete are as follows: 1. It is generally not possible to achieve the same area of reinforcement to area of concrete using steel fibres as compared to using a network of reinforcing bars of wires.
There is no grout loss, such as that from badly fitting formwork, which results in poor quality concrete like shown below. By careful selection of materials and finishing processes, a wide range of high quality finishes can be obtained.
Nominal Mixes In the past the specifications for concrete prescribed the proportions of cement, fine and coarse aggregates. However, due to the variability of mix ingredients the nominal concrete for a given workability varies widely in strength.
Cracks in reinforced concrete columns due to Steel Corrosion (cracks parallel to steel bars) 2. Cracks in reinforced concrete columns due to shrinkage of concrete 3. Cracks in reinforced concrete columns due to shrinkage of concrete 3. Cracks in reinforced concrete columns due to increased load on the slab 4.
This method is used where large quantity of concrete work is involved at greater height, where other means of transporting is not easy to do. This method is used where large quantity of concrete work is involved at greater height, where other means of transporting is not easy to do.
WHY WE TEST CONCRETE SRTRENGTH AFTER 28 DAYS? Tweet Why do we test concrete compressive strength after 28 days? The table below shows the compressive strength gained by concrete after 1, 3, 7, 14 and 28 days with respect to the grade of concrete we use.
It has many advantages when compared to the normal conventional concrete. The density is considerably reduced by using fly ash based cellular lightweight concrete than normal concrete and at the same time, the strength is not affected by appropriate design mix.
These are the environments to which the concrete will be exposed during its working life. No Environment Exposure Conditions 1 Mild Concrete surfaces protected against weather or aggressive conditions, except those situated in coastal area. Table below shows exposure conditions of these environments.
There are two ways of overcoming this problem: Embed another material in the concrete which is strong in tension – reinforced concrete Remove the tension altogether – by arching or prestressing. In practice, reinforced concrete beams are designed on the assumption that cracks will occur under their service loads.
The concrete shall be deemed to comply with the strength requirements if: a) every sample has a test strength not less than the characteristic value;or b) The strength of one or more samples though less than the characteristic value, is in each case not less than the greater of : 1) The characteristic strength minus 1.35
The following figures illustrate the precast concrete process: 1. The individual components are prefabricated off site then taken to site where they are erected. The individual components are prefabricated off site then taken to site where they are erected.
Following are the cases, which affect creep in concrete: When the aggregate volume is increased, creep will be less as the aggregate is more rigid than the cement paste. Water within the hardened cement paste is forced to more as a result of the applied load.
in dry conditions), it should be suitable for use in concrete. Aggregates: Quality of aggregates, its size, shape, texture, strength etc determines the strength of concrete. The presence of salts (chlorides and sulphates), silt and clay also reduces the strength of concrete.
Formwork pressures are function of height (including the height from which concrete is dropped into the forms) and are affected by concrete workability, rate of stiffening and rate of placing. Exceeding this limit may lead to unacceptable formwork deflections, loss of grout / concrete at joints, or even collapse.
Advantages of Concrete Shells Like the arch, the curved shapes often used for concrete shells are naturally strong structures, allowing wide areas to be spanned without the use of internal supports, giving an open, unobstructed interior.
Cleanliness: when repairing concrete, care must be taken to remove any dirt or dust that will prevent the repair concrete bonding with the parent concrete. Cleanliness: when repairing concrete, care must be taken to remove any dirt or dust that will prevent the repair concrete bonding with the parent concrete.
WHAT IS PRECAST CONCRETE? Tweet Precast concrete is cast under factory controlled conditions and not erected on site until it is fully hardened. Just like in-situ concrete, precast concrete can be plain, reinforced or prestressed concrete. No related posts.
Procedure for measuring bulk density of concrete is as per IS 1199 – methods of sampling and analysis of concrete. Procedure for measuring bulk density of concrete is as per IS 1199 – methods of sampling and analysis of concrete. ii) Fill the cylindrical measure with concrete as soon as practicable after mixing.
Related posts: SELF COMPACTING CONCRETE WITH TESTS TESTS ON HARDENED CONCRETE CHEMICAL TESTS ON CONCRETE STRUCTURES COMMON TESTS ON THE FRESH CONCRETE Removing concrete slab to build wood deck but worried about water entering basement? Tweet Loading GET LATEST TOPICS IN YOUR EMAIL- SUBSCRIBE NOW.
It is new technique involved in the civil engineering.Reactive powder concrete in made by replacing the conventional sand and aggregate by grounded quartz less than300 micron size, silica fume, synthesized precipitated silica ,steel fibers about 1 cm in length and 180 micron in diameter.
Advantages that make precast concrete cladding such an appealing option are: Durability: Assuming the panel design has been carried out with proper thought for rainwater flow over the surface of the building, it will weather well and not require frequent cleaning.
The stress strain curve of concrete lies between those of the aggregate and the cement paste. The aggregate is more rigid than the cement paste and will therefore deform less (i.e. have a lower strain) under the same applied stress. The aggregate is more rigid than the cement paste and will therefore deform less (i.e.
Both the rate and degree of hydration, and the resulting strength of the final concrete, depend on the curing process that follows placing and consolidating the plastic concrete. This reaction, called hydration, produces a stone-like substance—the hardened cement paste.
The concrete can be specified in two ways : a) by proportioning of the constituents /ingredients (nominal mix) b) by required strength (Design mix) Concrete is mixed by any two methods, based on requirement as per quality and quantity of concrete required.
Advertisement Hot Topics Recent Topics Most Viewed Most Discussed FOUR PHASES OF PROJECTMANAGEMENT WHAT IS PROJECTMANAGEMENT? Codes of practice impose limits on horizontal movement or sway.
hardened concrete). hardened concrete). hardened concrete). hardened concrete). hardened concrete). Procedure as per IS 516 – Methods of tests for strength of concrete 1. Also read Compressive Strength Test for Concrete Cubes for calculations and results.
This method is also used to find out 28 days compressive strength of concrete in 28 hours. (As As per IS 9013-1978-Method of making, curing and determining compressive strength of accelerated cured concrete test specimens). (As
Precast floor slabs: The main types of slabs are used in the precast frames are: Hollow cored slab Double tee slab Precast walls: Precast concrete walls serve two functions: Stability As walls or boxes surrounding staircases and lift shafts. Corner columns – not symmetrical at all.
Sulphate attack in concrete foundation and cement mortar below ground level. Movement in walls above ground level and expansion and deterioration of cement mortar and concrete below ground level. Foundation near to drains where drains are running below foundation and / or drains lacking concrete cover.
Prestressed Concrete Piles CLASSIFICATION OF PILES LOAD ON PILES NEGATIVE SKIN FRICTION ON PILES Can foundation Piles be welded, if yes what is the welding procedure to be followed? Advertisement Hot Topics Recent Topics Most Viewed Most Discussed FOUR PHASES OF PROJECTMANAGEMENT WHAT IS PROJECTMANAGEMENT?
Hybrid concrete construction can incorporate all the benefits of precasting, (e.g. Precast and in-situ concrete can be used together in many different ways to extend the design horizons for architects, engineers and contractors. economy, flexibility, moulability, continuity and robustness).
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