Redirect vs load view

When should I use redirect and when

Code:

$this->load->view('projects/page');

?
For example, in the following code snippet what will be more preferable to use?

PHP Code:

class Projects extends CI_Controller
{
   public function __construct(Type $foo = null)
   {
       parent::__construct();
       if (!$this->session->userdata('logged_in')) {
           $this->session->set_flashdata('flash_danger', 'Please login to view this page');
           redirect('home'); // maybe to use `$this->load->view` here?
       }
   }

   public function index()
   {
      ... 


And another question  - am I uderstand it right, that controller object (the object of class  Project) will being created every time I request to this controller?
So will the function  `__construct` be process every time before controller logic will be processed?