Investigate On The Preparation Of CBC Composite Material And Concrete Strength With Slag And Fly Ash

CBC(Chemically Bonded Ceramics)cementing material is widely noted as a environment-friendly material,prepared by some simple mechanical or chemical ac-tivations with large quantity of industrial solid wastes as raw materials.Compared with the traditional cement,CBC processing is simple without the need of high tem-perature sintering and cost is low with the high efficiency and environment-friendly.CBC is generally composed of 20%-70%slag powder,10%-20%fly ash,5%-30%Portland clinker and 5%-15%lime,which eventually formed-Si-O-Si-and-Si-O-Al-three-dimensional network structure with the characteristics of the ceramic.Therefore,the mechanical properties of CBC are better than ordinary Portland cement material and possessing high consolidation ability,especially under the circumstance that clay is involved,thus compared with cement CBC owns a good application prospect.However,there are less researches on the formation mechanism、properties and application of CBC cementing materials because of the great difference of composi-tion between CBC cementing material Portland cement.In order to realize large scale utilization of slag powder and fly ash,we systematically studied on the mixture ratio of slag powder and fly-ash cementing material and the mechanical properties of con-crete,and detailed analysis on the C30、C40 strength grade of concrete mixture ratio design and optimization of mixture ratio.In addition,due to the early strength of CBC cement concrete is weak.Therefore,we also research on the chemical activator and optimization combination to effectively solve the problem of low early strength in the preparation of CBC,and the curing methods of concrete with CBC cementing materi-al is used to further study.In this paper,the main research work and research results are as follows:(1)The raw materials need to be activated before production of CBC cementing materials.First,we will discuss the activation mechanism of industrial waste residue by analyzing the nature of the raw material,and the physical activation method is adopted according to the properties of slag powder,fly ash and clinker.Then the C40 and C30 of CBC cementing materials are designed based on the different proportions of fly ash,slag powder,clinker,lime and gypsum.(2)According to the design regulations of mix ratio of portland cement concrete and the properties of CBC cementing materials,the C30 flowing concrete was pre-pared,and identify the optimum ratio of the water cement ratio and the bone-glue ra-tio by the optimization experiments.The study shows that the compressive strength can reach 32.52MPa when the ratio of water cement and bone-glue is 0.48 and 0.43 respectively,which can meet the requirement of C30 flowing concrete.In addition,the ratio of C40 cementing materials and C40 flowing concrete are further researched based on the material ratio C30 flowing concrete of CBC cementing materials and the study results.The results showed that the compressive strength up to 39.55MPa with 0.53 water cement ratio and 0.39 bone-glue ratio,which can basically meet the design requirements of the C40 flow concrete.(3)By study the effect of different chemical additives on the compressive strength of CBC concrete.The results showed that the early compressive strength of concrete will improve significantly when the mixing ratio of sodium sulfate is 0.8%.At the same time,by the research and analysis the influence of natural curing,steam curing,temperature and humidity conservation,static stop time and curing time to the mechanical properties of concrete.The results showed that the curing effect of CBC concrete is best under the vapor pressure of 100℃ and compressive strength will im-prove with the increase of curing time.Based on the above research,we have prelim-inary mastered the curing methods,static stop time,additive types and adding amount of CBC cementing material concrete.(4)XRD analysis of the raw materials and CBC concrete showed that the main composition of the mineral chemistry of slag powder and fly ash are SiO2,Cao and Al2O3,and mineral phase is from silicate and vitreous.In addition,we found CBC concrete appears a small amount of crystal phase,which are mainly wollastonite,cus-pidine,silicon acid second calcium and other compounds.