Civil Engineering - Building Materials - Discussion

The bulking of sand which is the process by which sand increases in volume as a result of the presence of moisture content must be taken into account while proportioning of the aggregate. Moistened sand bulks greatly and increases in volume hence for each measure of moistened sand, the actual volume of sand particles becomes exaggerated so more sand should be taken to take care of bulking else the mix will be undersanded.

Good, thanks for explaining @Adebola.

These are provided along the transverse direction to allow the expansion and contraction of a concrete slab due to temperature and subgrade moisture variation.

They are intended to prevent potentially damaging forces accumulating within the slab itself or surrounding structures. Maximum spacing of expansion joints ranges from 25-27 m in jointed reinforced concrete slabs and from 40 m (for slabs <230 mm thick) to 60 m (for slabs >230 mm thick) in unreinforced concrete.