Study On Influence Of Manufactured Sand Shape Characteristics Of Limestone On Concrete Strength

The demand for concrete in the construction of China's port waterways is huge,and the natural sand resources are gradually deficient.The research on mechanism sand is one of the important issues for the development of China's transportation industry in the future.There are a large number of limestone resources in the eastern and central western regions of China that can be used as the mechanism sand mother rock.At present,the research on the sand particle shape of the mechanism is relatively limited,and the grain shape of the machined sand has an important influence on the mechanical properties of the concrete.Therefore,this article mainly focuses on the following aspects.First of all,from the main aspects of the sand-shape characteristics of the influencing mechanism,the literatures at home and abroad are studied.Then the basic theory of the granular shape and concrete strength of the sand is elaborated.At the same time,the concept of the grey system theory and its application in the concrete research are introduced..Then,the prismatic angle test and digital image processing technique analysis were carried out for different kinds of fine aggregates,and the data of angular characteristics and grain shape parameters of different types of mechanical sands and natural sands were preliminarily studied to obtain the grain shape parameters of limestone mechanism sands.Superior to other types of machined sand.Secondly,under the same mix ratio,the slump test and concrete compressive strength test were performed on five kinds of fine aggregates,and the correlation degree between the granular characteristic parameters and compressive strength of concrete was analyzed based on the grey correlation analysis method.According to the analysis,it can be concluded that the aspect ratio Rd has the greatest correlation with the strength of the machined sand concrete.Then the weights of the remaining parameters are calculated based on the obtained correlation degree,and the granularity characteristic coefficient Q is defined as the sum of the product of the four granular characteristic parameters and the product of their weights.The grain shape characteristic coefficient Q is used as a new index to characterize the sand grain shape of the mechanism.The test results show that the grain shape coefficient Q has a positive correlation with the concrete strength.Finally,the correlation coefficient of grain shape coefficient Q with other factors affecting concrete strength,such as water-binder ratio,machine-made sand MB value,and fly ash content,was analyzed using the grey correlation method.According to the analysis,the water-binder ratio is the factor that has the greatest correlation with the strength of the concrete,and the particle shape coefficient is the next.It shows that the coefficient of grain shape has a good correlation with the strength of concrete.Through the analysis of the sand particle shape test of the mechanism,the relationship between the grain shape characteristics and the strength of the concrete is discussed.