How long will Allan Block last (life expectancy)?

This is a subject that comes up quite often, but is truly a hard question to answer. Allan Block is manufactured by dozens of different companies around the world, which all have different aggregate and testing on their blocks.  Each block will act differently due to the type of aggregate and manufacturers output product.  With that being said, there is a set of standards that each block manufacturer must meet.  By achieving those minimum requirements, a life expectancy can be calculated.  Since the dry cast block industry looks to the National Concrete Masonry Association (NCMA) for guidance, that is where we can extrapolate a true life expectancy.  The NCMA puts a life expectancy of upwards of 100 years when the product is not exposed to chemicals that increase the breakdown of the concrete.  Since most retaining walls incorporate geogrid reinforcement, we have to look at the life expectancy of that material as well which the NCMA provides guidance of 75 to 100 years.  Since geogrid is the limiting factor in this case, the industry then can use a 75-year life expectancy of a retaining wall block.  With all this information, we have given a long answer to such a simple question!