How to Make Basic Concrete at Home - Quiz

Quiz Question

1. Concrete is a mixture of :
Cement
Fine aggregate (less than 5 mm diameter)
Coarse aggregate (gravel 6- 20mm diameter)
All of the above
2. The fine and coarse aggregates provides.
most of the bulk and strength of concrete
Elasticity of the concrete
3. The cements glue the individual particles together.
True
False
4. Cement is made from a mixture of clay and limestone which, when heated together, form a new substance. Once cooled this substance is ground to a fine powder and gypsum is added to produce cement.
True
False
5. In cold climates total setting can take five to six hours ____________ than it takes in hot weather.
Longer
Shorter
6. Most of the reaction and strength development of the concrete takes place
Over the first month
In later years
7. Hot weather brings other problems. If the aggregate is hot it will contribute to the temperature of the concrete mix as it hardens. This can lead to excessively high temperatures in the mix which will reduce the final strength of the concrete.
True
False
8. A simple wooden box fitted with handles can be fabricated of known volume. For example a box 300mm high x 400mm wide x 540 mm long has a volume of 65 liters. Two boxes full of aggregate will be sufficient to mix with a 50 kg bag of cement when making 1:2:4 mix concrete.
True
False
9. Concrete achieves its maximum strength with a water : cement ratio of 0.3 but this is not achievable when mixing by hand (the mix would be too dry to mix it properly).
True
False
10. The water cement ratio is calculated by dividing the mass of the water in the mix by the mass of the cement. For hand mixed concrete the minimum water cement ratio is usually considered to be 0.55 by weight. This is equivalent to 27.5 liters of water to every 50 kg bag of cement. If too much water is added, the water will replace the aggregates in the mix and lead to a weak concrete. The best way to mix concrete is in a concrete mixer. Mechanical mixers need less water to ensure complete mixing and produce a more consistent concrete.
True
False