Benefits of steel reinforced concrete slabs

Here are the benefits of steel reinforced concrete slabs:
• Steel reinforcing is simple to place.
• Steel reinforcing reduces random cracking.
• Steel reinforcing reduces and controls crack width and
helps maintain aggregate interlock.
• Displacement and curling can be minimized when steel
reinforced concrete is provided.
• Strength is increased with steel reinforced concrete—
even the smallest cross sectional area of steel reinforcement
will provide reserve strength of l 6 percent and more.
• Most importantly, steel reinforcement saves money over
the life of the slab.
• Finally, admixtures are not an alternative to steel reinforcement;
they both do different things in the concrete.

Therefore, admixtures cannot be substituted for steel reinforcement.
The steel reinforcement industry is dedicated to providing
quality steel reinforcement to the construction industry. It is
also essential that steel reinforcement be sized, spaced, and
placed properly. It is vital to have a well-graded and compacted
granular subbase.
Of course, total quality can only be achieved when well
qualified suppliers and contractors are on the construction
sites.
References
1. Lanning, Anne, “Synthetic Fibers,” Concrete Construction, July 1992.
2. Ringo, Boyd C., and Anderson, Robert B., “Designing Floor Slabs On
Grade Step-by-Step Procedures Sample Solutions and Commentary “Second
Edition, The Aberdeen Group, 1996.
3. Anderson, Robert B., “Innovative Ways to Reinforce Slabs-On-
Ground” WRI Publication TF-705, 1996.
4. “Supports for Welded Wire Reinforcements in Slabs-On-Grade,” WRI
Publication TF-702.

Compression test for concrete, should test cubes or test cylinders be adopted?

Basically, the results of compression test carried out by using cubes are higher than that by cylinders. In compression test, the failure mode is in the form of tensile splitting induced by uniaxial compression. However, since the concrete samples tend to expand laterally under compression, the friction developed at the concrete-machine interface generates forces which apparently increase the compressive strength of concrete.

 However, when the ratio of height to width of sample increases, the effect of shear on compressive strength becomes smaller. This explains why the results of compression test by cylinders are lower than that of cubes. Reference is made to Longman Scientific and Technical (1987).

This question is taken from book named – A Self Learning Manual – Mastering Different Fields of Civil Engineering Works (VC-Q-A-Method) by Vincent T. H. CHU.