Although, it would be expected that there were not differences between as-designed and as-built layer thicknesses, the practice shows differences due to excess or imperfection because of the lack of accuracy during constructive processes or poor quality control. Construction tolerances on layers thicknesses allowed by Colombian specifications for highways construction are shown by Table 1 Invias, 2007.
Aunque lo ideal sería que no existieran diferencias entre los espesores de las capas terminadas y su correspondiente diseño, la realidad es que se presentan diferencias que pueden ser por exceso o por defecto, y que son debidas a la falta de precisión de los procesos constructivos o a deficiencias en control de calidad.