Dim timeString1 As String = "11:00:00"
Dim timeString2 As String = "00:05:00"
Dim time1 As TimeSpan = TimeSpan.Parse(timeString1)
Dim time2 As TimeSpan = TimeSpan.Parse(timeString2)
Dim timeResult As TimeSpan = time1.Add(time2)
Console.WriteLine(timeResult.ToString())