Experimental Study On Seismic Behavior Of Recycled Aggregates Concrete Brick Masonry Under Freeze-thaw Cycle

Masonry structure has a long history in our country, and still been the main form ofbuilding structure in some small cities and rural areas. Recycled concrete brick wouldbe the main development direction of masonry materials in future for it could be fullused of construction waste and complied with environmental concept. In many cities ofthe north, freeze-thaw environment has great influence on the masonry structuredurability, and the effect of seismic performance with the degeneration of masonrystructures durability could not be ignored. Domestic and foreign researches on masonrystructures under freeze-thaw environment are less, therefore, the masonry structuresdurability and seismic performance researches are necessary and urgent.Four brick walls specimens were designed, the freeze-thaw cycles system and thefreeze-thaw test of masonry walls specimens was developed based on simulationlaboratory system in the paper. The seismic performance indicators of specimens underlow cyclic loading tests, for example, the destruction process and characteristics, energydissipation capacity, stiffness degradation, ductility and so on was analyzed in differentfreezing and thawing cycles. The results show that: with the increase of freeze-thawcycles, the seismic performance indicators of walls falling, the energy dissipationcapacity continues to decline, the shear capacity and stiffness, ductility decreasedsignificantly. The test results could not only provide the reference for the evaluation ofthe existing masonry structure reliability, but also provide theoretical support for theimprovement of current code in future.Combing with statistics and analysis of test results, this paper puts forward thetrilinear restoring force simplified model of recycled aggregates concrete brick wallconsidering freeze-thaw damage, defines the formula of the model’s feature points, the loading and unloading stiffness degradation and hysteretic rule. It will providetheoretical support and computation basis for masonry structure seismic responseanalysis that considering freeze-thaw damage in the future.Numerical simulation of masonry walls has been made utilizing finite elementanalysis software ABAQUS based on experimental investigation. Load-displacementcurve which is monotonously increased is obtained by importing Stress-strainrelationship and elastic modulus in different frequency of freeze-thaw cycle. As a resultof comparative analysis, the calculating results agree well with the experimentalstructure, and it verifies the consistency and accuracy of the model. This paper will lay afoundation of multi-parameter and deep dynamic analysis on masonry structure underfreeze-thaw environment in the future.