Durability assessment of Gerdoi and red travertines from Azarshahr, East Azerbaijan province, Iran

摘要

Durability is the most important characteristic of stones in sustainable architecture. Salt crystallization has been known to damage porous building stones. Gerdoi and red travertines are extensively used in new buildings in East Azerbaijan province. To this end, petrographic and physical properties, dry and saturated P-wave velocity, uniaxial compressive strength and Brazilian tensile strength were obtained for each freshly quarried stone in the laboratory. The samples were subjected to an aging test in order to examine their resistance against sodium chloride crystallization. Water saturated-to-dry strength ratio (a crude immediate estimator) and a decay function model were applied to assess durability of stones. Gerdoi travertine consists of alternation of densely packed layers (laminated fabric) while red travertine exhibits massive fabric. Albeit Gerdoi travertine has laminated fabric, it shows higher initial strength, P-wave velocity and lower effective porosity and water absorption than Gerdoi travertine. The results showed that a crude immediate estimator is not a sensitive indicator for estimating durability of travertine stones. P-wave velocity, uniaxial compressive strength and Brazilian tensile strength decreased with increasing number of salt cycles. A decay function model confirmed that the integrity loss was higher in red travertine in comparison with Gerdoi travertine. It was found that the integrity loss of both stones based on Brazilian tensile strength is highest than those based on uniaxial compressive strength and P-wave velocity.