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ABSTRACT In order to study the fatigue performance of composite beam with steel-plate-concrete composite deck under fatigue load, both static test on two specimens and fatigue test with constant-amplitude fatigue [...]

A new type of composite slab is introduced in this paper, which is composed of normal flat steel plates and concrete slabs, connected and interacted by perfobond shear connectors (PBL shear connectors). Experiments on six specimens of this type of composite slab, loaded at two symmetric two-points, were described in this paper to get mechanical behaviors under bending moments. During the experiments, the crack patterns, failure modes, failure mechanism and ultimate bending capacity of specimens with composite slab were investigated, and the strains of concrete and flat steel plates were also measured and recorded in order to obtain the moment action. From the experimental results, it was found that composite interaction between the steel plate and the concrete fully developed, and such composite slab was verified to have good mechanical performance with high bending capacity, substantial flexural rigidity and good ductility. Plane section assumption was also verified and moreover, a design approach including calculation methods of bending capacity and flexural rigidity was established and proposed based on the experimental results, and the calculation methods were also verified and revised on the basis of comparisons of the calculated results and experimental results. Results from this paper provide references for the application of this new type composite slab.

Soil contamination with heavy metals has caused serious environmental problems and increased the risks to humans and biota. Herein, we developed an effective bottom up metals removal system based on the synergy between the activation of immobilization metal-resistant bacteria and the extraction of bioaccumulator material (Stropharia rugosoannulata). In this system, the advantages of biochar produced at 400 °C and sodium alginate were integrated to immobilize bacteria. Optimized by response surface methodology, the biochar and bacterial suspension were mixed at a ratio of 1:20 (w:v) for 12 h when 2.5% sodium alginate was added to the mixture. Results demonstrated that the system significantly increased the proportion of acid soluble Cd and Cu and improved the soil microecology (microbial counts, soil respiration, and enzyme activities). The maximum extractions of Cd and Cu were 8.79 and 77.92 mg kg–1, respectively. Moreover, details of the possible mechanistic insight into the metal removal are discussed, which indicate positive correlation with the acetic acid extractable metals and soil microecology. Meanwhile, the “dilution effect” in S. rugosoannulataprobably plays an important role in the metal removal process. Furthermore, the metal-resistant bacteria in this system were successfully colonized, and the soil bacteria community were evaluated to understand the microbial diversity in metal-contaminated soil after remediation.