HTML Textbox showing default value as 0 for int data field

[Tamexhissemes]

I have a textbox which is holds int data field. When the page loads, 0 appears by default. Following is the code for displaying text box : \[code\]<%:Html.TextBoxFor(model => model.Ssn, htmlAttributes: new { @class = "txtBox txtBoxMediumSmall" })%>\[/code\]where model.Ssn is a int.
Why isn't is blank? And what should be done to make it blank?
Please let me know if more information is required.