Experimental study on recycled steel fiber concrete
Some basic properties of recycled steel fiber aggregate were tested, such as surface features, water absorption, apparent ensity, crushing index, cube compressive strength and so on. Recycled steel fiber aggregate were used to replace the natural aggregate by 0%, 25%, 50% and 100% proportion to make concrete. Afterward, compressive strength, splitting tensile strength and flexural strength were investigated at ages 3, 7 and 28 days. The results showed that thorn appearance of recycled steel fiber aggregate makes packing density decrease, crushing value and absorption increase. The compressive strength, splitting tensile strength and flexural strength of the recycled concrete depend on the mix proportions. Generally, the strength of recycled concrete can be 15–25% lower than that of concrete made with virgin aggregate.
On the study and application of steel fiber reinforced high strength concrete
The strengthening mechanism of SFRHSC(steel fibre reinforced high strength concrete)and some examples of engineering applica-tion are introduced.The present status of the research and engineering application of SFRHSC were summarized.The application foreground of SFRHSC was discussed.In addition,some problems for the study and application of the SFRHSC were brought forward.
Semiautomated quantification of the fibrous tissue response to complex three-dimensional filamentous scaffolds using digital image analysis.
Fibrosis represents a relevant response to the implantation of biomaterials, which occurs not only at the tissue-material interface (fibrotic encapsulation) but also within the void fraction of complex three-dimensional (3D) biomaterial constructions (fibrotic ingrowth). Usual evaluation of the biocompatibility mostly depicts fibrosis at the interface of the biomaterial using semiquantitative scores. Here, the relations between encapsulation and infiltrating fibrotic growth are poorly represented. Virtual pathology and digital image analysis provide new strategies to assess fibrosis in a more differentiated way. In this study, we adopted a method previously used to quantify fibrosis in visceral organs to the quantification of fibrosis to 3D biomaterials. In a proof-of-concept study, we transferred the "Collagen Proportionate Area" (CPA) analysis from hepatology to the field of biomaterials. As one task of an experimental animal study, we used CPA analysis to quantify the fibrotic ingrowth into a filamentous scaffold after subcutaneous implantation. We were able to demonstrate that the application of the CPA analysis is well suited as an additional fibrosis evaluation strategy for new biomaterial constructions. The CPA method can contribute to a better understanding of the fibrotic interactions between 3D scaffolds and the host tissue responses.