- Methods for assess WORKABILITY such as Compacting Test, Slump Test, Vebe Test and Flow Test. Why Important..u can get from Material in Construction Book Page 61-65.
- The example and explaination about Fineness Modulus Of Fine Aggregates u can read from page 52-54 in Material in Construction Book. (Fineness modulus is a measurement of the coarseness or fineness of a given aggregate. For a fine aggregate, FM is calculated from the cumulative percentages of aggregate retained on sieves different size divided by 100. FM is an index of the fineness of an aggregate-the higher the FM the coarser the aggregate. Different aggregate grading may have the same FM. FM of fine aggregate is useful in estimating proportions of fine and coarse aggregates in concrete mixtures).
- Aggregates affect the strength of concrete - GRADED Aggregates should range in size so that they fit together well. This gives a stronger and denser concrete. Rounded aggregates give a more workable mix. Angular aggregates make concrete harder to place, work and compact, but can make concrete stronger (This only example...Need more explaination).
- As per excercise in lecture on 11/8/2009. But the answer no need to use the FORM
- The differences between Ordinary Portland Cement, Sulphate Resisting Portland Cement and Rapid Hardening Portland Cement in term of compound composition, fineness and usage you can get the answer from Material in Construction Book page 42-46 and Bahan Binaan: Asas Konkrit Teching Module page 7-9.
- Typical relationship between compressive strength and w/c ratio such us Low water to cement ratio leads to high strength but low workability. High water to cement ratio leads to low strength, but good workability. The physical characteristics of aggregates are shape, texture, and size. These can indirectly affect strength because they affect the workability of the concrete. If the aggregate makes the concrete unworkable, the contractor is likely to add more water which will weaken the concrete by increasing the water to cement mass ratio. Time is also an important factor in determining concrete strength. Concrete hardens as time passes. Why? Remember the hydration reactions get slower and slower as the tricalcium silicate hydrate forms. It takes a great deal of time (even years!) for all of the bonds to form which determine concrete's strength. It is common to use a 28-day test to determine the relative strength of concrete. Concrete's strength may also be affected by the addition of admixtures. Admixtures are substances other than the key ingredients or reinforcements which are added during the mixing process. Some admixtures add fluidity to concrete while requiring less water to be used. An example of an admixture which affects strength is superplasticizer. This makes concrete more workable or fluid without adding excess water. A list of some other admixtures and their functions is given below. Note that not all admixtures increase concrete strength. The selection and use of an admixture are based on the need of the concrete user. (Only Example..need more)
- Accelerators speed up the hydration (hardening) of the concrete. Typical materials used are CaCl2 and NaCl.
Retarders slow the hydration of concrete, and are used in large or difficult pours where partial setting before the pour is complete is undesirable. A typical retarder is table sugar, or sucrose (C12H22O11).
Air entrainments add and distribute tiny air bubbles in the concrete, which will reduce damage during freeze-thaw cycles thereby increasing the concrete's durability. However, entrained air is a trade-off with strength, as each 1% of air may result in 5% decrease in compressive strength.
Plasticizers (water-reducing admixtures) increase the workability of plastic or "fresh" concrete, allowing it be placed more easily, with less consolidating effort. Superplasticizers (high-range water-reducing admixtures) are a class of plasticizers which have fewer deleterious effects when used to significantly increase workability. Alternatively, plasticizers can be used to reduce the water content of a concrete (and have been called water reducers due to this application) while maintaining workability. This improves its strength and durability characteristics.
Pigments can be used to change the color of concrete, for aesthetics. - See Material in Construction Book page 115-120 and also My Lecture Note.
- Concrete Masonry Units (CMU) Processing
10. Sintering is a method for making objects from powder, by heating the material in a sintering furnace below its melting point (solid state sintering) until its particles adhere to each other. Sintering is traditionally used for manufacturing ceramic objects, and has also found uses in such fields as powder metallurgy (Need more explaination)
11. Board Of Engineers Malaysia (BEM) function see the official website http://www.bem.org.my.
12. The Function Of (Visit the Official Website below..)
a) Construction Industry Development Board (CIDB) - www.cidb.gov.my
b) Standard & Industrial Research Institute Of Malaysia (SIRIM) - www.sirim.my
c) Public Work Department (JKR) - www.jkr.gov.my
d) Contractor Service Centre (PKK) - http://pkk.kkr.gov.my
Ini sekadar TIPS..and ada juga yang saya bagi Jawapan...So please do Your Totorial.
Sakam Ramadhan Daripada Saya. Tks
No comments:
Post a Comment