Keep in mind that QlikView always stores values as Dual values. That means that the values always have two components, one text part and one numerical part. The text part is the visual value that you actually see in the application, and the underlying numerical part is the one used for calculations and processing.
If you apply the Num() function on your date values, you will see if the underlying number is an integer or a decimal value. For example you could do this in a listbox showing the date field, and then ad an expression to the list box showing the corresponding numerical value for your dates.
Num( DateField )
If your field has underlying decimal values, the value represents a timestamp. The integer part is the date and the decimal part is the fraction of a day that the time represents.
As Jonathan pointed pointed out above you can eliminate the decimal part in a value by using the Floor() function. For an opposite scenario where you want to remove the integer part in order to generate a time value, you can use the Frac() function.
Always keep in mind to validate the underlying values, to ensure your data integrity.