HOW TO GET URINE SMELL OUT OF CONCRETE
Urine odors on concrete areas such as patios and driveways are often powerful and difficult to remove. Concrete is porous. When urine lands on a concrete area, it bonds tightly to the concrete as it dries, penetrating deep within its pores. This can make odor removal particularly difficult.
That terrible stench lingers long after the liquid has been absorbed, and can last months unless treated properly. To really get these odors out, make sure you're eliminating them, not just covering up the smell (like many products do).
Use a cleaning product with enzymes and live bacteria to break down and eliminate the source of the tough odors. Simple Green Outdoor Odor Eliminator uses safe, naturally-occurring bacterial microbes that eliminate odors at the source.
Directions:
For best results, use product during cooler times of day such as dawn or dusk.
Tip: Every third or fourth time you apply the product, you should give the concrete a quick scrub and rinse with plain water to avoid buildup.