Two layovers in two months

I will be flying through China twice in two months with my flight itinerary (once in April for three hours, and once in June for nine hours). Do I need an actual visa for China, since I will be in the airport on two occasions this calendar year, or can I simply get two 24-hour direct transits, since I will not be leaving the airport? I am flying from Canada to Australia, and have a three hour layover in Guangzhou. I will be staying in Australia for two months, and then headed from Australia back to Canada with a nine hour layover in Guangzhou.