Study On The Influence Of Waste Cathode Ray Tube Glass Sand With Different Particles Sizes On Concrete Performance

With the continuous development of civil engineering,the use of concrete is increasing year by year,and the natural sand as a raw material for concrete is continuously reduced,so the search for alternative materials for natural sand has become the focus of research on concrete sand.At the same time,along with the rapid development of electronic technology,Cathode Ray Tube(CRT)to be being washed out gradually,to produce a large amount of waste CRT glass.Due to the high content of heavy metals such as lead,antimony and iron in waste CRT glass,direct use of waste CRT glass may cause environmental pollution;current research shows that as long as the proportion of waste CRT glass sand is controlled within a reasonable range and the waste CRT glass sand is used to replace river sand and mixed into concrete,it will not cause pollution to the environment and can meet the basic performance of concrete and improves the ability of concrete to prevent γ-rays.However,there is little research on the influence of the particle size of waste CRT glass sand on the performance of concrete.Because the grinding of waste CRT glass sand is laborious,time-consuming and costly,the waste CRT glass sand mixed into concrete does not need to be ground fine.It can meet the requirements of concrete performance and will bring greater practical application value.In this paper,the different particle sizes waste CRT glass sand was used to prepare radiation protection concrete,the following conclusions were obtained:1.The waste CRT glass sand was divided into four kinds of maximum particle sizes,which were 4.75 mm,2.36 mm,1.18 mm and 0.60 mm respectively,and used as fine aggregate to replace 25% river sand.With the decrease of the maximum particle size,the slump and apparent density of the concrete decrease,the compressive strength and modulus of elasticity increase first and then decreases.When the maximum particle size of the waste CRT glass sand is 2.36 mm,the strength of concrete is the maximum.2.The alkali aggregate expansion reaction of waste CRT glass sand with different particle sizes was studied by rapid alkali-silicic acid reaction.As the maximum particle size of waste CRT glass sand decreases,the expansion value of mortar decreases.However,there is a most unfavorable particle size in the alkali aggregate reaction.The most unfavorable particle size of the waste CRT glass sand in this test is 2.36 mm.When the particle size is larger than or smaller than the particle size,the reaction expansion value will be reduced.3.Lead leaching of waste CRT glass sand concrete with different particle sizes was studied by leaching toxicity identification method.With the decrease of the maximum particle size,the leaching amount of lead increases,but all met the requirements of 5.0mg/L stipulated by the US environmental protection agency for the leaching of toxic properties.4.Through γ-ray shielding test,waste CRT glass sand can improve the radiation protection performance of concrete.With the decrease of the maximum particle size,the linear absorption coefficient of concrete increases,the thickness of the half decay layer and the ten times of the thickness of the decay layer decrease,resulting in better shielding performance of concrete.5.The performance of different grades of waste CRT glass sand concrete is numerically simulated by using PFC3 D discrete element software.From the collapse cloud diagram of concrete,it can be seen that the slump value of concrete decreases with the decrease of the maximum particle size.The results are consistent with the experimental results.