Transport properties of concrete after drying-wetting regimes to elucidate the effects of moisture content, hysteresis and microcracking

Abstract

Drying and wetting induce a number of microstructural changes that could impact transport properties and durability of concrete structures, but their significance is not well-established. This research examines pastes, mortars and concretes with different w/b ratios, binders, aggregate sizes, curing and conditioning regimes. 50 mm thick samples were dried to equilibrium at either 105C, 50C / 7% RH, 21C / 33% RH or gentle stepwise at 21C / 93% RH  3% RH, and then rewetted stepwise by humidification at 21°C / 33% RH  86% RH and full saturation to produce varying degrees of damage and moisture content. Oxygen diffusivity and permeability, electrical conductivity, microcracking, accessible and total porosity were measured at different conditioning stages over 3-year period to better understand the effects of shrinkage, hysteresis and drying-induced damage on transport properties. The effect of supplementary cementitious materials (GGBS, SF) and implications of dryingwetting on concrete durability are discussed.

Seismic Damage Model of Bridge Piers Subjected to Biaxial Loading Considering the Impact of Energy Dissipation

“…The diminution of a structure's self-weight provides several advantages. For example, excessive hydration heat produced by cement hydration can be reduced to mitigate the thermal cracking of massive concrete piers and thus may increase the durability of concrete [1,2].…”

Assessment of enclosing structure moisture regime using moisture potential theory

“…where 1 F -moisture potential of enclosing structure section, which contacts with outside air, Pa, N F -material moisture potential next to enclosing structure surface, which contacts with inside air, Pa.…”

“…Errors in overwetting protection design can reduce enclosing structure durability and result in premature failure of the building [1][2][3][4][5]. Moisture in enclosing structure thickness influences both on power saving properties of building thermal protective shell [6][7][8][9][10][11], and on human health [12].…”

Unsteady-state moisture behavior calculation for multilayer enclosing structure made of capillary-porous materials

“…Error in construction material moisture condition assessment can result in premature deterioration of the enclosing structure [1,2], high heat loss of the building [3,4], and negative humidity effect on human life [5].…”