Research On The Durability Of Low-clinker Cement

With implement of sustainable development strategy, resourcesn energy and environmental problems become the main factor to restraint the cement industry. Low-clinker cement, which is produced from little portland cement clinker and more industrial waste residue, is a task of environmental and economic assignment. Fly ash and coal gangue are the largest amount waste residue, exiting low-clinker cement has much shortage in durability. In this paper, low-clinker cement is mainly developed from fly ash and coal gangue, in order to build tow new gel system, and admix concrete with various good performances. This paper emphasizes on durability of low-clinker cement and concrete in those subjects investigated. The main research contents and the result of the study in this article are generalized as the following:First, correlation between admixture ratio and strength of compound cement is determined from test, so as to determine mixture ratio of,composite material selected. Result of this part is the theoretical foundation of two low-clinker cements mixture test.Second, according to phase composition and reactivity of fly ash and coal gangue , mixture ratio is determined from orthogonal test. Test of fundamental characteristics shows that these two kinds of low-clinker cement measure up to standard of 32.5MPa cement. At the same time, SEM microstructure shows the hybrid cement paste and the aggregate-paste interfacial zone are improved in different extent. The result of this part is also the foundation of the following researches.Later on, part of durability properties of low-clinker cement are researched, especially long-term strength, reinforcement corrosion, carbonization performance, sulphate erosion, et. Test shows that low-clinker cement dominates on long-term strength and sulphate erosion, falls short on carbonization performance and reinforcement corrosion, but much better than slag cement. All those just show tow kinds of low-clinker cement have better durability.Last, part of fundamental and durability performances of low-clinker cement concrete are researched, especially workability and physical mechanical performance in fundamental performance, impermeability frost resistance and auto-shrinkage in durability performance et. Low-clinker cement is similar to ordinary cement concrete in fundamental performance, but dominates on above durability performance, especially chloride ion erosion is much improved.Each of the two kinds of lwo-clinker cement in this paper can meet the challenge of general civil engineering, and has the extensive engineering application perspective.