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In this present article, I intend to interpret and argue that Critical Literacy or Critical Language Awareness is a meaningful concept for ESL learners to transparently understand and English educators need to apply it in their daily educational practices. Through reviewing the relevant literatures, the theoretical knowledge of Critical Literacy is introduced at first. The second part concentrates on explaining the importance of implementing Critical Literacy in the instruction of ESL. Finally, rooted in former researchers' findings and argumentations, I elaborate on the analysis of the predictable difficulties and barriers about the cultivation of Critical Literacy for both native and non-native English speakers. In a meanwhile, some suggestive strategies are provided respectfully so as to assist ESL instructors to cope with these problems at the practical stage.

The accelerated carbonation, natural carbonation, fast freeze-thaw test, and pore structure analysis of C30 and C50 concrete with different proportions of iron tailings powder and slag powder were tested, respectively. The results show that the accelerated carbonation depth and natural carbonation depth of concrete increase with the increase of iron tailings powder content. The prediction model of carbonation depth of iron tailings powder concrete is established by introducing the iron tailings content coefficient and strength influence coefficient. The error between the calculated value of the model and the test value of 28 d curing concrete natural carbonation depth is small, which proves that the model is completely feasible. When iron tailings powder accounts for 50% of mineral admixture, it is helpful to improve the frost resistance of concrete. According to the pore structure analysis, the introduction of iron tailings powder can optimize the pore structure, improve the porosity of harmless and less harmful pores, and thus improve the frost resistance.

Tailings are one of the largest solid wastes in stock at present. In order to improve the comprehensive utilization rate of tailings, especially to solve the problems of fine-grained tailings treatment, the concrete composite admixture was prepared by using iron tailings powder and slag powder. In order to study the influence of iron tailings powder on the workability and long-term mechanical properties of concrete, C30 and C50 concrete with different iron tailings powder dosages were prepared, and the slump, expansion, flexural strength, splitting tensile strength, and compressive strength of concrete at different ages were tested. The results showed that the proper addition of iron tailing powder is beneficial to the working performance of concrete and can effectively reduce the time-loss of concrete fluidity. When the content of iron tailings powder in the composite admixture is 50%, the 1080d long age strength of C30 and C50 concrete can reach 50.3 and 80.7 MPa. Based on the 28d compressive strength, the relative strength-age prediction model of iron tailings powder concrete was established. The calculation and experimental results show that the model can accurately predict the compressive strength of micro-powder concrete of iron tailings at long age, and the error rate is less than 1%. The results lay a theoretical foundation for the utilization of iron tailings in concrete.