Damage evolution in cement mortar due to erosion of sulphate

Abstract

a b s t r a c tUltrasonic technique is used to detect the velocity change of stress wave propagated in the cement mortar immersed in the solution of sodium sulfate for 425 days. Also the density change of specimens at different erosion time is measured. By curve fitting, the effect of solutions' concentration and water/cement ratio on the damage evolution is analyzed. The SEM observation on the growth of delayed ettringite is also performed. It shows that the damage evolution of specimens attacked by sulphate solution is dominantly induced by the nucleation and growth of delayed ettringite, and the average size of microvoids in cement mortar affects the damage evolution significantly.

Effect of sea water and MgSO4 solution on the mechanical properties and durability of self-compacting mortars with fly ash/silica fume

“…Seawater contains about 2800-3000 mg SO 4 À per liter and when those ions move into the concrete, they will react the solution of calcium hydroxide to form solid ettringite called as delayed ettringite [15]. Usually, the nucleation and growth of the delayed ettringite occur in the micro voids in cement mortar materials [13][14][15][16]. If the delayed ettringite will grow and touches to the boundary of the voids, producing an expansion force to cement mortar materials.…”

“…Because seawater movement can cause great damage to marine and offshore structures [14]. Seawater contains about 2800-3000 mg SO 4 À per liter and when those ions move into the concrete, they will react the solution of calcium hydroxide to form solid ettringite called as delayed ettringite [15]. Usually, the nucleation and growth of the delayed ettringite occur in the micro voids in cement mortar materials [13][14][15][16].…”

Study on the evolution of dynamic mechanics properties of cement mortar under sulfate attack

“…The second is concerne d with the changes in the performanc e of concrete structure s under sulfate attack, which includes changes in compress ive strength, damage and durability of cement mortar [11][12][13][14][15][16][17][18]. Moreove r, the damage evolution, Young's modulus and Poisson's ratio was carefully evaluated through wave speed measuremen ts considering specimens of cement mortars with different water to cement ratios [19]. The third category focus on material modification of concrete resistance to sulfate attack.…”

Evolution of surface hardness of concrete under sulfate attack

“…Mironova et al investigated the effect of liquid push out of the material capillaries under sulfate ion diffusion in cement composites [12]. Chen et al studied damage evolution in cement mortar immersed in sodium sulfate solution for 425 days using ultrasonic techniques [13], and measured the growth properties of delayed ettringite and 0950-0618/$ -see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.conbuildmat.2013.11.107 gypsum by virtue of XRD method [14]; Zhang et al tested the static and dynamic modulus of ettringite [15], and investigated the evolution of flexural strength of concrete due to sulfate attack [16]; Zhu et al studied the expansion strain of concrete immersed in sodium sulfate solution, and developed an increment model for expansion strain based on damage evolution [17].…”