Perlite & Asparagus

A friend has given me 2 bags of 100 litres (yep, that's 200 litres!) of Perlite....! I have pretty heavy clay soil up at the allotment, but am hoping to set up a new asparagus bed this year and wondered if I could add the perlite to help with the drainage? What are your thoughts...?

I'd recommend the sharp sand and gypsum as well. Eventually, as the perlite reaches the surface it can blow away and create another problem.