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his paper studies the feasibility of preparation high strength fired bricks from iron tailings with addition of clay and coal gangue. The results indicated that the optimum conditions were found to be that the hematite tailings content were 35%–50%; the firing temperature was 1000 °C. Under these conditions, the mechanical strength, the water absorption and the bulk density of the fired bricks were 21.17–26.14 MPa, 14.55–15.47% and 1.648–1.629g/cm3, respectively, these were well conformed to standards MU20 of Chinese Fired Common Bricks Standard (GB/T5101-2003).The phase composition and microstructure of the fired specimen were characterized by XRD and SEM. The results showed that the major crystalline phases present in fired brick were quartz, albite, amphibole, hematite and muscovite, and glass phase encapsulated and cement the crystalline phases forming strong entirety which promoted the strength of bricks.

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The compressive strength of ultrafine white cement samples at three ages: 3, 7 and 28 days and micro appearance of hydrates were tested. The influence of the usage of superplasticizers on the compressive strength of ultrafine white cement paste and hydrates were investigated. The results indicated that the 28d compressive strength of ultrafine white cement with 3% naphthalene based superplasticizers added was 92.9 MPa, 22.9% of that of pure ultrafine white cements (75.6 MPa). The addition of superplasticizers was beneficial to the density of white cement paste. A large number of hydrates (AFt, C-H-S, and so on) were generated in the capillary pores, which would improve the structure of capillary pores of hardened cement paste, increase the density and strength.