How to manage time in php?

Question

PHP

Good night, there is an array in it

array(3) { 
[0]=> string(8) "00:05:23" 
[1]=> string(8) "06:23:00" 
[2]=> string(8) "05:00:00" 
}

How to add this time so that it turns out 11:28:23, given that the array will be added with new values?
ps maybe for the question it is necessary to clarify that the format is H: i: s