## Function

- In the heat of hydration analysis, the restrictions applied to the stress analysis model are convection limit, adiabatic limit, and prescribed temperature limit. Convection limit (or heat transfer limit) is the limit at which heat is transferred between the ambient and temperature analysis model. The characteristic of heat transfer on the convection limit is defined with the convection coefficient.
- The surface of convection limit includes the surface of the concrete and the surface that was cast continuously during the construction stage. The convection coefficient assigned to the convection surface limit affect the temperature of the material surface. If the thickness of the material is comparatively small the coefficient affects the internal heat transfer of the material. The convection coefficient is assigned considering the existence of a form, type of material, thickness of material, maintenance time, curing method, and ambient velocity of wind.

## Call

From the main menu, select **[Load] tab > [Type : Heat of Hydration] > [Heat of Hydration Analysis Data] group > [Convection] > [Convection Coefficient Functions]**

## Input

**Add** : Click to add a convection coefficient function.

**Modify** : Click to modify a previously defined convection coefficient function.

**Delete** : Click to modify a previously defined convection coefficient function.

**Close** : Click to close the dialog box.

**If Add/Modify is clicked**

Convection Coefficient Functions dialog box

**Function Name** : Enter the name of the convection coefficient function.

**Function Type** : Enter the type of the convection coefficient function.

**Constant Type** : Convection coefficient is constant over time.

**Convection Coefficient** : Specify the constant convection coefficient.

**User Type** : Define the variation of convection coefficient over time in a table format.

**Time** : Time over which coefficients are defined

**Coefficient** : Coefficients relative to time

Convection coefficients selected from Korean Concrete Standard Specification (1996)

NO. | Curing method | Average value (kcal/㎡h˚C) |
---|---|---|

1 | Metallic form (Steel) | 12 |

Watering (Watering depth below 1 cm) | ||

2 |
Watering (Watering depth 1 cm to 5 cm) |
7 |

Straw bag curing | ||

3 |
Watering (Watering depth 5 cm to 10 cm) |
7 |

4 | Plywood | 7 |

5 | Sheet | 5 |

6 |
Curing mattress Watering + Curing mattress Watering + Sheet |
4.5 |

7 | Forming polystyrene (thickness 5 cm) + sheet | 1.5 |