Quantifying the Effect of Ammonium Nitrate Attack on Mechanical and Physical Properties of Cement Mortars

Abstract

The purpose of the current study is to quantify the effect of ammonium nitrate attack on the mechanical and physical properties of cement mortars. After 28 days of curing, the mortar specimens were immersed in ammonium nitrate solutions with 5%, 20% and 50% concentrations. The specimens were then tested after 10, 20, 40 and 60 days. The results showed that at 5% and 20% concentrations, the compressive strength loss of cement mortar after 60 days of exposure was 23% and 43%, respectively. For 50% concentration, the loss in compressive strength reached 55% at 60 days of exposure. At 50% and 20% concentrations, the porosity of cement mortar increased by 10.9% and 3.9% after 60 days of exposure, respectively. The loss in the bulk density at 5% and 20% concentrations of ammonium nitrate solution after 60 days of exposure was about 3% and 6%, respectively. The increase in porosity and the losses in compressive strength and bulk density could be overcome by using high compressive strength concrete, pozzolanic additives and low water-cement ratio.