Study On The Effect Of Aggregate Particle Size And Mixture On Alkali-aggregate Reaction

Alkali aggregate reaction refers to the reaction of alkali and the active substances in the aggregate to form expansive colloids to cause concrete damage,the study of alkali reactivity abroad earlier,and our country until 1990 or so began to attach importance to the problem of alkali aggregate reaction The Aggregate particle size and grading are important factors affecting the reaction of alkali aggregate.At present,scholars have studied it,but because of the difference of test methods and environment,the results are different.In order to solve this difference,it is necessary to study the effect and mechanism of aggregate size and gradation on alkali aggregate reaction.Mineral mixture is one of the important measures to inhibit the alkali aggregate reaction,and the activity and specific surface area as an important indicator of the mixture,it is necessary from these two aspects to study its impact on the alkali aggregate reaction.At the same time,we further study the mechanism of the mixture to inhibit the reaction of alkali aggregate.In addition,the effect of the mixture on the inhibition of ASR is related to the curing age,it is necessary to investigate the inhibition admixture timeliness.Alkali aggregate reaction can cause concrete cracking and damage,which will affect the strength of concrete,dynamic elastic modulus,pore structure,etc.Therefore,it is necessary to explore the relationship between Expansion amount and strength,dynamic elastic modulus and other indicators in order to comprehensively evaluate the alkali Aggregate reaction.Firstly,through Fast mortar bar method made of different particle size and grading alkali aggregate reaction test,we get a expansion rate data of specimens with different particle size and grading.Summed up the different particle size and grading specimens the law of change of expansion rate with age,combined with the strength and dynamic elastic modulus data presented optimum aggregate grading.Through different mixtures of alkali aggregate reaction test,the influence of specific surface area and activity of the mixture on the reaction of alkali aggregate was analyzed,the swelling rule of different mixed material specimen was found to change with time,At the same time the use of mathematical methods for data processing,the mixed material suppression of alkali aggregate reaction timeliness was analyzed from the perspective of suppressing the rate and the mixed material content of 20% fly ash and 5% silica fume with an timeliness was proposed.By Matlab numerical simulation,the long-term prediction of the inhibition of ASR expansion by the mixture was carried out and it is concluded that the long-term effectiveness of inhibition of expansion is directly related to the content of the mixture.Through the strength and dynamic elastic modulus test,summed up the change rule of strength and dynamic elastic modulus with age with different mix ratio,and the influence of the ASR deterioration on the strength and the dynamic elastic modulus was analyzed,and the correlation curve and regression formula of ASR deterioration stage of expansion and strength and dynamic elastic modulus change are obtained by using data processing software.Through the stomatal scan test,the effect of ASR deterioration on the internal pore structure of the specimen was analyzed,and the correlation curve and regression formula of expansion and Pore structure related parameters were obtained.By electron microscopy and energy spectrum analysis,the relationship between microscopic element composition and m ASR oscopic expansion of the gel was studied,It is found that the Ca / Si ratio of the gel is an important factor affecting the expansion.At the same time,the relationship between the number and distribution of the gel and the expansion was analyzed by using the micrograph.Finally,it was found that the microcosmic element composition,quantity and distribution of the gel were consistent with the specimen expansion variation.