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Red-bed soft rock covers a large area in China and is often used as filling materials for highway roadbed and embankment, while the disintegration of red-bed soft rock often causes serious settlement of the roadbed and decreased stability. To thoroughly study the disintegration properties of red-bed soft rock, a series of slake durability tests were performed using different test methods. First, the gradation of disintegrated red-bed soft rock was investigated, and the shape of the gradation curve mainly presented as reverse sigmoidal and hyperbolic. Moreover, the evolution model of the disintegration breakage of red-bed soft rock using the Morgan-Mercer-Florin (MMF) model was derived, and the model parameters were analysed. Based on the test results, the disintegration behaviours of red-bed soft rock were measured by the disintegration ratio; then, the new formula to calculate the disintegration ratio based on the concept of the traditional disintegration ratio was derived using the established model. Finally, the effect of different test methods, i.e., different test devices, drying temperatures and sizes, on disintegration breakage under cyclic wetting and drying was analysed, and the test results showed that the rate of disintegration was accelerated by the slake durability apparatus, a higher drying temperature and a larger size. • The evolution model of disintegration breakage based on the Morgan-Mercer-Florin (MMF) model was derived and verified. • The effect of different test methods, i.e., different test devices, drying temperatures and sizes, on the disintegration breakage under cyclic wetting and drying was analysed. [ABSTRACT FROM AUTHOR]

Objectives: Complications during contraceptive implant removal are important for users and programs. We describe breakage rates during Sino-implant (II) removals at four Chinese family planning clinics., Study Design: We collected data by observation of consecutive removal cases and subsequent data transcription onto a standardized case report form. Three sites used the "pull out" removal technique, and one site used the "U" technique., Results: Sino-implant (II) rods were removed from 318 women. There were 16 implant breaks (5.0%), with the breakage rate varying by site from 0% to 7.4%. All 16 breaks occurred at the three sites that used the standard "pull out" technique. Six implants were cut by the scalpel, five were snapped by the clamp, and five were unspecified. Other contributing factors included deeper or wider positioning of the implants (n=6) and implants that were enveloped by thick fibrous tissue (n=3). There was no relationship between breakage rate and duration of implant use. Less than 1% of removals took more than 10 min., Conclusions: Both the standard "pull out" technique as well as the "U" technique can be used to remove Sino-implant (II). Breakage during implant removal may not be problematic if all fragments of the rod are readily removable. Breakage occurs with predictable low frequency, and training is needed to assure that providers can deal with breakage events., Implications: Contraceptive implant removal complications are important for users and programs. These are some of the first data on breakage during removal of Sino-implant (II). More than one removal technique can be used, but training is required to ensure that providers can deal with the infrequent implant breaks., (Copyright © 2014 Elsevier Inc. All rights reserved.)