If next/prev posts exist, the next/prev button will show.
What i did here is to modify the next/prev labels 🙂
while( have_posts() ) :
// Your loop
endwhile;
// Pagination
$pagination_args = array(
'prev_text' => '<i class="fa fa-chevron-right" aria-hidden="true"></i>Previous post',
'next_text' => 'Next post<i class="fa fa-chevron-left" aria-hidden="true"></i>' ); ?>
<div class="paginate_container"><?php echo paginate_links( $pagination_args ); ?></div>