Define general information about the concrete.

Parameter	Description
Type	Specifies the type of concrete. Concrete can be Normal weight, All Lightweight, or Sand Lightweight.
Strength, f'c	This is the strength for the material as defined by most common specifications. This strength is normally defined as the stress value at a strain of 0.003 at 28 days.
Unit Weight	This is the unit weight of the material which is used along with f'c to calculate the modulus of elasticity. If the number in this input field turns red, the value does not conform to the unit weight limits defined for the concrete type in LRFD 5.2.
Unit Weight with Reinforcement	This is the effective unit weight of the material and includes an allowance for reinforcement. This unit weight is used to compute self-weight.
Mod. Elasticity, Ec	Select the check box if you want to override the computation of modulus of elasticity and enter your own value. If the check box is unchecked, Ec will be computed based on f'c and Unit Weight using the application equations for the selected concrete model (AAAHSTO LRFD, ACI 209R-92, or CEB-FIP).
Max. Aggregate Size	Enter the maximum dimension of the concrete aggregate. This value is used to check minimum reinforcement spacing requirements per LRFD 5.10.3.1.2.

NOTE: Beginning with AASHTO LRFD 7th Edition with 2016 interim provisions, All Lightweight and Sand Lightweight has become simply Lightweight concrete. If you select All Lightweight or Sand Lightweight and your Project Criteria is based on AASHTO LRFD 7th Edition with 2016 interim provisions or later, your concrete will be considered to be Lightweight.