Looking for a formula to take short dates from multiple cells and paste into a single cell with spaces in between.

E.g

A1 - 01/01/2017
A2 - 15/02/2017
A3 - 24/03/2017

A4 = 01/01/2017, 15/02/2017, 24/03/2017

Tried using the formula for copying text (=(A1&" "&A2.......) but the result displays as 5 digit numbers)

Any help would be appreciated.