Abstract
Chicken feathers are composed mainly of avian keratin, a fibrillar protein with a complex structure, and important properties such as durability, hydrophobicity, being chemically unreactive, and depending on the specific function can change its morphological and inner structure. This study takes advantage of these features and for the first time the use of keratin from chicken feathers to modify characteristics on expansive soils is reported. Swelling characteristics of remolded expansive soil specimens were studied through varying the percentage of keratin fiber content using 0.25, 0.50, 1.00 and 3.00 wt%. One-dimensional swell-consolidation tests were conducted on oedometric specimens, specific surface area was determined using methylene blue, and degree of saturation was also analyzed. Finally random distribution and interaction between keratin structures and soil were studied by scanning electron microscopy. The results show that randomly distributed fibers are useful in restraining the swelling tendency of expansive soils. The maximum reduction of pressure (43.99%) due to swelling is achieved by reducing the void ratio, which can be reached with the addition of chicken feather keratin structures to the expansive soil. Finally, the mechanism by which discrete and randomly distributed fibers reduce swelling pressure of expansive soil is explained.
Highlights
In the field of geotechnical engineering, it has long been known that swelling of expansive soils caused by moisture change results in significant distresses and in severe damage to overlying structures
The value of void ratio depends on volumetric changes of soils; in order to evaluate the effect of keratin over these parameters in soils, void ratios were studied in all samples as well as swelling pressure
In this graph it is possible to appreciate that keratin barbs diminish the values of pressure needed to return to initial void ratio in the soil, since all curves with modified soils are below the natural soil
Summary
In the field of geotechnical engineering, it has long been known that swelling of expansive soils caused by moisture change results in significant distresses and in severe damage to overlying structures. Shrinking and swelling are aggravated by wide swings in the water content, which are due to climatic conditions and wide variations in the rainfall; in addition expansive clays soils are extensively distributed worldwide [1]. These facts cause severe safety and economic problems [2]. An adequate model is presented by Tang et al [13]; they considered that the bonding force between the fiber and the contact area of soil particles contributes to the
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
