Structural analysis of reinforced concrete beams affected by alkali-silica reaction with focus on material models for concrete

Abstract

Alkali-silica reaction (ASR) is a chemical reaction that occurs in concrete between the alkalized cement and silica within the aggregates. ASR produces a gel around the aggregates which absorbs water, expands, results in local stresses, and causes the concrete to crack internally and externally. Research on this chemical reaction and development of concrete models including this reaction has been extensive. However, limited research about the structural effects of ASR and load actions due to ASR has been carried out. Due to lack of applicable constitutive models including the effect of ASR in finite element softwares, simplified methods for the assessment of ASR damaged reinforced concrete structures are used.

In this master thesis structural analyses of reinforced concrete beams affected by ASR have been carried out. Analyses on one span- and three span beams have been carried out to study the effect of using more complex concrete material models which includes the stress dependency of the ASR expansion and the stiffness reduction due to ASR. The load actions due to ASR with different concrete material models are computed and compared. From the case studies it was found that the non-unifrom ASR expansion and the stress dependency of the ASR expansion had significant impact on the load actions.