SynopsisAn experimental study of the viscosity and principal normal stress difference of a polystyrene melt filled with aramid (Kevlar), glass, and cellulose fibers is reported. The influence of loading level and mastication on the rheological properties is discussed. The effects of mixing and mastication on fiber damage are considered. Glass fibers break down rapidly to very small aspect ratios, while aramid shows a "kinked" structure, with kinks occurring every 100 pm. A mechanism is proposed for fiber breakage based on buckling during rotation in shear flow. It is found that addition of fibers increases the viscosity in the same manner as a reduction in temperature, and data may be superposed by reduced plotting. This indicates that the viscosity increase is due solely to enhanced viscous dissipation in the matrix and not to interparticle forces as is the case with smaller particles. The principal normal stress difference increases at fixed shear stress with fiber loading. The extent of increase depends upon fiber loading, aspect ratio, and modulus.
The search for durable and sustainable construction materials inspires the developments in the world of cement concrete, as well as in the world of concrete-polymer composites. Both worlds recognize, strive for and accept each other's contribution to the synergic effects that are realized by the combination of classical building materials and polymers. A better knowledge of materials behaviour, especially in the field of admixtures, and a better understanding of curing processes allowed the development of highly performing mineral or modified mineral concretes, mortars and grouts. CPC-science becomes an invaluable element in the development of sustainable construction materials. ICPIC organises practitioners and scientists, dealing with concrete-polymer composites in all industrial fields, but with emphasis on construction industry. The 11th International ICPIC Congress took place in Berlin, 2-4th June 2004. New trends and evolutions have been presented and discussed. The highlights of the Congress, and the synergies that emerge from the congress for the construction world in combination with cement concrete, will be presented and discussed in the paper.
Sustainable development is one of the leading civilization ideas. This term means such a development that satisfies the present needs without a limitation of the possibility of satisfying the needs in the future. Sustainable development in construction is particularly important, as this branch of the industry is consuming enormous amounts of mass and energy. A new research area has been created by this idea. The new fields of investigation are involved with material, energetic, and environmental conditions, but also with such topics as protection against noise and the methods of the evaluation of the efficiency of waste materials storage. Implementation of the idea of sustainable development in the construction industry will be a source of scientific and engineering inspiration for many years to come.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.