Penetration of water into cracked geopolymer mortars by means of neutron radiography

Abstract

Water transport into cracked fly ash geopolymer mortars were investigated, for the first time, using neutron radiography. Three samples were prepared and cracks were induced in these samples. The first sample does not contain internal waterproofing additives, the second contains Lignosulphonates based waterproofing admixture and the third sample was covered with external waterproofing slurry coat. Neutron radiography images were acquired continuously during the moisture absorption process. The results obtained showed that water absorption into first sample is the fastest. The internal waterproofing additives minimized water absorption into the second sample. The waterproofing slurry coat stopped water ingress into the third sample for 109 min, however after that time it started to absorb water from the crack region only. Water is fed to all portions of the samples from the water filled cracks. The advance of water from the cracks into the matrix of the samples follows the square root of the absorption time.