Filler materials are gaining widespread popularity and becoming very important because they help in increasing some of the mix properties and also lower the usage of binder which is usually more expensive
Here is the table showing some common filler materials along with binders
| Material |
Binder |
Filler |
Importance of filler |
| Concrete |
cement |
gravel, stone , sand |
cheaper |
| Drywall |
gypsum |
cardboard |
tenacity, volume, main part |
| Particle board |
Synthetic Resin, glue |
sawdust |
tenacity, volume, main part |
| Plastic explosive |
Plasticizer, oil |
explosive |
explosiveness |
| Tyre rubber |
rubber |
Soot |
Volume, better mechanic properties |
| Resin epoxy |
epoxy |
Microspheres |
Improve viscosity of resin |
posted in Concrete Engineering |
CONTINUOUS BEAMS AND ONE-WAY SLABS
The ACI Code gives approximate formulas for finding shear and bending moments in continuous beams and one way slabs. A summary list of these formulas follows. They are equally applicable to USCS and SI units. Refer to the ACI Code for specific applications of these formulas.
For Positive Moment
End spans
If discontinues end is unrestrained wl 2 n / 11
If discontinues end is integral with the support wl 2 n / 14
Interior spans wl 2 n / 16
For Negative Moment
Negative moment at exterior face of first interior support
Two spans wl 2 n / 9
More spans wl 2 n / 10
Negative moment at other faces of interior supports wl 2 n / 11
Negative moment at face of all supports for slabs with spans not exceeding 10ft (3m) and (b) beams and girders where the ratio of sum of column stiffness to beam stiffness exceeds 8 at each end of the span wl 2 n / 12
Negative moment at interior faces of exterior supports, for members built integrally with their supports
Where the support is a spandrel beam or grider wl 2 n / 24
Where the support is a column wl 2 n / 16
Shear Forces
Shear in end members at first interior support 1.15 wl n / 2
Shear at all other supports wl n / 2
End Reactions
Reactions to a supporting beam, column, or wall are obtained as the sum of shear forces acting on both sides of the support.
posted in Concrete Engineering |
American Society for Testing and Materials (ASTM) specifications cover renforcing steel. The most important proper- ties of reinforcing steel are
1. Modulus of elasticity E s , lb/in 2 (MPa)
2. Tensile strength, lb/in 2 (MPa)
3. Yield point stress f y , lb/in 2 (MPa)
4. Steel grade designation (yield strength)
5. Size or diameter of the bar or wire
posted in Concrete Engineering |
The tensile strength of concrete is used in combined-stress design. In normal-weight, normal-density concrete the tensile strength can be found from
___
f r = 7.5Ö f ’ c lb / in 2 in USCS units
___
f r = 0.7Ö f ’ c MPa in SI units
posted in Concrete Engineering |
The modulus of elasticity of concrete E c adopted in modified form by the ACI Code can be calculated by the formula given below:

posted in Concrete Engineering |