Experimental Study On Mechanical Properties And Durability Of Iron Mine Tailings Self-compacting Concrete

The iron mine tailings self-compactingconcrete is a new self-compactingconcrete mixed with a certain amount of iron ore tail in place of natural sand as fineweight self-compacting concrete. Base on the research of work performance in theprevious period, the paper researches and analyzes the age change law of basicmechanical properties in early period for the iron mine tailings self-compactingconcrete, the structure characteristics of microscopic void and durability test. Themain results include the following aspects:1. It has the similar laws for the cube compressive strength of ISCC-2andSCC-1which varies with age, and the strength close to it more or less. Although therewill be a discrete, the change curve of axes resist compression strength for ISCC-2,which varies with age, is similar to the SCC-1on growth trend. It is affected little bythe age for the relationship between compressive strength and tensile strength, and itcan introduce the same formula to fit the analysis of data for ordinary self-compactingconcrete and iron mine tailings self-compacting concrete in tension and compressionratio.2. Elastic modulus of iron mine tailings self-compacting concrete is similar toordinary self-compacting concrete. When compressive strength of iron mine tailingsself-compacting concrete reaches to the range of high strength concrete, it canintroduce the formula of (3.22) for comparison of data fitting, and the result is closest.But when the compressive strength continues to grow, the curve will be lower. Itshould not be applied to the iron mine tailings self-compacting concrete. Meanwhile,it should also not be applied to computing iron mine tailings self-compacting concretefor the model of elastic modulus by calculating the low strength self-compactingconcrete.3. It has the same change laws for the mercury curves of ISCC-2and SCC-1.From the range of3000psia to6000psia, the phenomenon is that the amount ofaccumulated mercury rises rapidly for ISCC-2. While before this range, the curve rises slowly. However, when the pressure reaches this range, the mercury levelsincrease dramatically, and the mercury rate is greater than the SCC-1significantly.4. In the experiment of mortar-pressure mercury holes testing, the test samples isimpacted significantly by the sampling parameters, which means, it has a greaterimpact by the man-made factors. In general, we can also find the change law. Thespecimen pore size distribution approximates to normal distribution for the two kindsof conjunction ratio based on SCC-1and ISCC-2self-compacting concrete. Highestpoint of the normal distribution is the most probable aperture，and the highest point islocated in environmentally sound holes within norms. The content of harm hole forISCC-2is greater than SCC-1, but the porosity of ISCC-2is significantly less thanSCC-1.5. Experiment results of chloride ion impermeability of SCC-1and ISCC-2allmeet a good performance levels of the resistance to chloride ion erosion. The DRCMof ISCC-2is greater than SCC-1. According to structure analysis of the microscopicpore, the phenomenon is due to that the harmful hole and multi-harm hole of theISCC-2is greater than SCC-1in the proportion.6. It shows non-linear trend for the carbonation depth of SCC-1and ISCC-2which varies with carbonation-age, and the carbonation depth for both of them isclose to each other with the change of age. At the same time, it can be seen that thedepth of carbonation is faster in the early development of carbonation. When thecarbon age is more than14d, the growth rate of carbonation depth is graduallysmaller with the change of age. Data points of carbonation depth and compressivestrength of respective Self-compacting concrete is more discrete for each other, butpopulation remains a significant linear growth trend.