Footing and Foundation Inspection II

1. Footing and Foundation Inspection II Module five

2. Review • When suitable materials are used in making concrete what will it influence? • workability, strength, durability, appearance and cost • What 2 materials would adversely affect the curing of concrete if it happened to be part of the mix? (slow or speed curing) • sugar will slow curing • salt will speed curing

3. Review • After how many days should concrete reach its required strength if cured properly? • 28 days • What is the best temperature for curing concrete? • 23º C

4. Review • What are some of the possible causes of excessive concrete shrinkage? • improper design mix • to much water • inadequate curing • lack of protection from • wind, high or low temperatures

5. Review • In very cold conditions an additive that is commonly used in concrete is calcium chloride. What must you be aware off? • when using calcium chloride with reinforcing steel in the concrete it will cause corrosion and possible surface cracking

6. Module Five Houses that have basements require that the foundations be: • structurally sound • resistant to water penetration • comfortable If you build during cold weather you need to understand how freezing causes damage.

7. Freezing Pressure caused by freezing is • 9 Mpa / °Cup to 200 Mpa @ -20°C • when water freezes its volume increases by 9% • volume increases will depend on the type of soil adjacent and below foundations • considerable volume changes will occur in fine sand, silt and clay

8. Protection Protection of soil prior to placing concrete will prevent problems • placing concrete on frozen soil will lose heat to the soil and may freeze, resulting in lower strength • protect the soil by covering with • 12” of straw, minimum of 3” insulating blankets • cover with plastic/tarps and introduce mechanical means of heat

9. Work period Do exercise 1 and 2