Alkali Silica Reaction - Diagnosis

  1. Hobbs (1988) recommends answering each of the following questions before pronouncing alkali-silica reaction as the original corrosion perpetrator.
  1. According to Hobbs (1988), if map cracking exists in unreinforced or lightly loaded concrete, oriented cracking occurs in unreinforced or lightly loaded concrete, the macrocracks are visibly discolored, gel is exuding from the macrocracks, and there is visible expansion of the concrete, ASR is the probable cause.
  1. ASTM C 856 Petrographic Examination
  1. Ultrasonic Pulse Velocity
  1. X-ray diffraction and infra-red spectroscopy produce charts of the minerals in the concrete.
  1. Resonant frequency will change with increased deterioration in the concrete.