Study On Maoming Kaolin Tailing Sand Cycle Used In Construction

With the rapid development of the building industry and the importance of environmental protection,now natural sand can not meet the needs of engineering,and the mine tailings currenting did not make appropriate use of,so it is very necessary to use tailings artificial sand to slove problem between resource and environmental.Therefore,this article mainly on test study of Maoming kaolin tailing sand cycle used in construction and main content are as follows:The system comparative analysis of the various indexes of the physical properties was used in between Maoming kaolin tailing sand and natural sand as fine aggregate in construction.The results showed that small particle tailing sand quite a lot,tailing sand are less than river sand in soundness,bigger edges and comers and larger surface roughness than the river sand,and the other is close to the river sand.The system study of tailing sand,river sand,sea sand and crushed sand on particle morphology and microstructure analysis by equipment of analyse particle image and scanning electron microscopy.The results showed that the roundness of the fine aggregate from the grain size 5.00mm～160μm,the roundness of crushed sand is smallest,followed by the tailing sand, and the river sand is very the same as sea sand;the particle of aggregate is bigger than 1.25mm ordiary have a bigger roundness,but the particle smaller than 1.25mm ordiary have a smaller roundness.Natural sand particles is sleek,less angular,crushed sand particles is rough and more edges and comers,and the tailing sand is in the middle of natural sand and crushed sand.The study of tailing sand and river sand mixed in tailing sand on solve the problem of optimization of tailing sand grading,influence of species and volume of mineral admixture,the distribution of particle size,water reducing and ratio of water and cement to the performance of cement mortar made by tailing sand.The results showed that the fluidity and compressive strength of cement mortar made by tailing is smaller than river sand,but higher than river sand on flexural strength;the fluidity of tailing sand motar mixed with river is basically an increase in the proportion of linear;the best ratio of tailing sand mixed with river sand is 6:4.Silica fume, rice husk ash and metakaolin are not good for the enhancements of workability of mortar,but can enhance the cohesion of its sticky and capacity of water-holding,also can enhance its strength,but fly ash,limestone and quartz gray have opposite effect of tailing sand mortar.Slag is good for both workability and mechanical;with the single-volume of fly ash and slag,the fluidity of tailing sand mortar is increasing,but the strength of fly ash mixed is downward trend, but upward trend with slag mixed.The particle size of slag contribute to the strength of tailing sand morar is below 30μm,particles size larger than 40μm are not good for wordability of mortar.With the volume of water reducing,the fluidity of tailing sand mortar is increasing,but the strength of it is decreasing.Finally,study of preparation C40 and C65 high performance concrete in use of kaolin tailing sand,on the basis of it,C100 high performance concrete was successful prepared by using tailing sand,too.The results showed that:a,the workability of C40,C65 concrete prepared by use of tailing sand was less than by use of river sand,and after the use of river sand mixing, performance of concrete significantly improved.The workability performance of C65 concrete was good when carried out in accordance with the ratio of 6:4 between tailing sand and river sand,Slump reached 245mm,the expansion degree of 600mm,down time of barrel is 23s;the compressive and splitting tensile strength of C40 and C65 use of tailing sand in every age was higher than natural sand prepared;The resistance to penetration of chloride ions into tailing sand concrete of C40 and C65 by ASTM C1202 and NEL,have reached a evaluation standard of "low",and with the improvement of strength and age period of growth,tailing sand concrete of resistance to penetration of chloride ions has obviously increased;b,The workability performance of C100 high performance concrete prepared by use of tailing sand was good, slump reach 230mm,the expansion degree was 530mm,down time of barrel for 23s,the performance of it is less than river sand;the use of slag and silica fume and superplasticizer make concrete very strong.The compressive strength of C100 tailing sand concrete in age of 28d is higher than concrete prepared by river sand,and the rate of early strength development was quick;the influence of resistance to penetration of chloride ions into C100 concrete used either tailing sand or natural sand is not very different,and early of coulomb electric charge at 6th and Cl~- diffusion coefficient on C100 tailing sand concrete sharp decline,tends to slow in the future.The researches in the thesis would establish basis for study and application of tailing sand concrete,and the test results would also provide important references for constituting technical specification of tailing sand concrete.