How to put simple MVC4 checkbox without model binding?

I am developing MVC4 application. I am having troubles in getting checked value in checkbox. I am using MVC4 razor. I am receiving null in the controller action method. This is my Index.cshtml code.

 @for (int i = 0; i < Model.EmploymentType.Count; i++)
  {
  @Html.CheckBoxFor(m => m.EmploymentType[i].isChecked, new { id = "employmentType_" + i })
  @Html.HiddenFor(m => m.EmploymentType[i].checkBoxName)
  @Html.DisplayFor(m => m.EmploymentType[i].checkBoxName)
  } 

this is my actionmethod.

[httpget]
 public ActionResult Index(int? clientId,DateTime?,bool? employmentType_0)
{

}

In the above action method I am receiving null value for employmentType_0 This is my class

public class logDetailsEnumeration
{
  public List<checkboxClass> EmploymentType { get; set; }
}
       public class checkboxClass
        {
        public int checboxID { get; set; }

        public string checkBoxName { get; set; }

        public bool isChecked { get; set; }
        }

I have initialised with checkboxes in controller as follows.

EmploymentType = new List<checkboxClass>
                {
                 new checkboxClass { checkBoxName = "ChangedValues" }
                }

May I know Why I am getting null values on back in controller on form submit? Thank you.