Strong Coupling of Freeze-Thaw Cycles and Alkali Silica Reaction - Multi-scale Poro-mechanical Approach to Concrete Damages -

Abstract

This paper aims to upgrade the poro-mechanical scheme to simulate concrete volume change and damages which are strongly coupled with both alkali silica reaction (ASR) and freeze-thaw cycles (FTC). The interaction of two impacts are modeled by considering ASR gel intrusion and ice formation in micro pores and crack gaps, gel movement and unfrozen water suction into entrained air, gel and water migration through cracks as well as equilibrium and mass conservation of both concrete skeleton and mixed pore substances. For the assessment how the proposed numerical scheme works, sequence of events on ASR and FTC is focused on. It shows that ASR can reduce the FTC expansion for nonair-entrained (non-AE) case, but increase the frost damage for air-entrained (AE) concrete. Similarly, the FTC damaged concrete will have a smaller ASR expansion for non-AE case, but a greater expansion when AE admixture agent is dosed. The simulated behaviors also agree well with past experiments of combined ASR and FTC. Finally, the analysis on short-term strength shows that the ASR damaged concrete has a higher residual compressive strength and ductility rather than FTC damaged one due to viscous ASR gel which stand for broken symmetry of damage fields.

Multi-scale computational modeling for concrete damage by mixed pore pressures – case of coupled alkali–silica reaction and cyclic freeze/thaw

“…A simplistic rate-dependent model of ASR gel flow is assumed as: where V̇ ASR→AIR is the speed of gel flow into air bubbles, k AIR is a constant which can be determined by the sensitivity analysis (3 × 10 −9 Pa −1 s −1 ), β ASR→AIR = V ASR→AIR / Air is the ASR gel occupying ratio in the air bubbles (0-1) and Air is the total air content (entrained and entrapped air). The functional air bubbles for the frost resistance is around 10 per cent of the total air volume (Gong et al , 2017; Promentilla and Sugiyama, 2010). Thus, if the ASR gel occupation ratio is larger than 10 per cent, the frost resistance from entrained air will totally disappear.…”

“…Deterioration process of concrete is of high complexity since structural concrete usually suffers from 29 coupled mechanistic and multiple ambient actions, such as high cycle fatigue loads, alkali silica reaction (ASR), 30 freeze-thaw cycles (FTC), carbonation and steel corrosion. Considering the complexity of durability problems 31 in terms of the coupling effects in chemical, physical and mechanical processes, a multi-scale modeling system 32 is necessary to provide a strong linkage between each process and concrete material itself.…”

“…ASR gel intrusion and ice formation in pores considering the pore size and shape(Gong et al, 2017) 12…”

Coupled thermo‐hydro‐mechanical analysis of reinforced concrete beams under the effect of frost damage and sustained load

“…The second method is an integrated thermo-hydromechanical approach which is developed by the authors in the past. [20][21][22][23] This approach is beneficial to capture the structural damage behaviors from the stage of concrete casting and curing until the usage under various material and environmental conditions. [21][22][23] In this article, thermo-hydro-mechanical simulation of structural behaviors under the coupled effect of frost damage and sustained load is carried out.…”

Stiffness Evaluation and Current Status of a Degraded Road Bridge Slab Located in a Mountainous Area

“…Moreover, the relationship between the degradation tendency of bridges and the regional characteristics causing salt damage, ASR, and frost damage is also a problem that needs to be solved. Since structural concrete usually experiences the combined effects of ASR, carbonation, freeze-thaw cycles, steel corrosion, and high-cycle fatigue loads (Gong et al 2017), concrete degradation is a complex process. As a part of the present study, a statistical analysis (namely, survival analysis) (Maki et al 2017) was performed using the inspection data for bridges in the Hokuriku region to solve the above problems.…”