as gator said there are some things that lime does. however in the examples he listed you would have to introduce a water lime mixturer to the soil in the amount of 50% or better to the soils your mixing it to. also the content of clay in canada is somewhat rare, the amount that i am talking to mix in is less than 10% and is only to bind the soil together. lime is one key additive to make concrete. as your track dries over the first couple of weeks it will harden similar to concrete it absorb more water and hold it in longer, which helps to prevent the track from cracking which then leads to it breaking up and potholing. also with it staying together better, tighter, it will blue groove much faster for big ROAR events and thus provide better traction. if you track is exposed outdoors when it rains it will absorb that moisture better and faster so you can get back to racing sooner.as for soil expansion it does not stop that if you have high clay soil only excessive water when doing a new build with very limited compaction will help prevent expansion. if mix lime with those soils without the proper amount of lime and water will only cause it to severally crack when it starts to expand since the lime will bind it but only to a point,ultimately it will expand and break up even worse. plus when lime mixed with soil is wet down it becomes tacky and provides better traction during club night racing when your watering your track. the theory of using soda or other compounds that tracks use on thier on raod tracks, only becoms slick once watered, as tacky as there are dry once wet its like drive a zamboni without studded tires.