Study On Wrapped Shell Modification And Its Application In Building Materials Of The Baking-free Ceramsite From Dredged Sediments

With the process of industrialization and the increase of dredging quantity in China, a large number of dredged sediment, which has large area, high moisture content and complex composition, is easy to produce two pollution. Therefore, it is very important to explore a new way for the utilization of dredged sediment.This paper is devoted to the exploration of the dredging preparation of brick, not only can effectively solve the dredged sludge disposal problem, the development of new building materials, in line with national policy guidance, and energy saving and waste, protection of land resources in China, wide application prospect.At present, the use of dredged sediment preparation brick no industrialization reports,most of the research work of sediment and cement and other materials directly mixed and pressed into brick.The bricks prepared by direct incorporation of low strength, poor water resistance, freeze-thaw resistance difference and a series of problems, basically no practical value. To solve this problem, this paper puts forward the dredging preparation of unbaked ceramic, and the mixed cementitious material, pressed into brick process, solve the problem of compatibility of sediment and cementitious materials.Aiming at the problems of low strength, poor freeze-thaw resistance and so on, this paper systematically discusses the technology of ceramic shell modification, which can improve the performance of ceramsite.The main research contents and results of this paper are as follows.Research results of ceramsite shell modification: (1) Particle size analysis: after modification of the sediment ceramsite, most of the particle size concentrated in 3-8mm, 8#and 9# mainly concentrated in 5-8mm. (2)The strength:the ceramsite with additive B ,15#-19# average single strength is relatively high, but in single, the shell wrapped the longest time the highest strength of 5# wrapped ceramsite, reached 2.47MPa, shell thickness of the 9# intensity reached 1.99MPa. (3) Frost resistance: the lowest mass loss rate of 9# ceramsite, the loss rate after the 21 freeze-thaw cycle is about 1.99%. Which add additives B, the frost effect is very obvious overall.Study results of modified wrapped ceramsite cement specimens: (1) Density:compared with 20# sintered ceramsite cement specimens, all specimens density is less than 2.0g/cm3, could meet the basic light requirements.(2)Water absorption: the water absorption of all ceramsite specimens is less than 7%. The group which with additives B , the overall water absorption rate is low, 19# ceramsite cement specimens has the lowest water absorption ,it is 4.38%.(3) Frost resistance: 3#, 4#, 5# cement specimens have good frost resistance, especially the longest shell wrapped 5#, after the freezing thawing in 21 times,the rate is only 7.42%. The most thick shell 9#, after 21 times freeze-thaw loss rate was only 2.04%. From 15# to 17#, with the increase of the amount of additives B, the frost resistance effect of the specimens gradually became stronger. Especially the 17#performance is optimal, after 21 times the mass loss rate is only 11.22%.The ceramsites were prepared for bricks. And the results showed that: (1) The strength :The wrapped shell brick single block test strength greater than 12Mpa, reach Mu 15 standard; the waterproof ceramsite brick single block test strength greater than 8Mpa,reach Mu10 standard.(2) The frost resistance: The frost resistance of ceramic tiles after 25 freeze-thaw cycles, the mass loss rate is less than 5%,which meet the use. (3) The waterproof aggregate and aggregate wrapped shell preparation process, can greatly improve the aggregate strength, which about water resistance, freeze-thaw resistance, they can be used as the basic raw material of building materials.