This research concerns moisture absorption through nanoclay/vinylester composites in artificial seawater medium and the resulting properties of degradation. Cloisite 15A, an organomodified nanoclay, and Cloisite Na, a naturally occurring nanoclay, were studied to examine the influence of organomodification on the moisture ingress behavior of the nanocomposites processed by using ultrasonication and twin-screw extrusion. Although X-ray diffraction and transmission electron microscopy analysis revealed exfoliation of Cloisite 15A in vinylester, Cloisite Na was only intercalated. Moisture diffusivity decreased by 72% due to the addition of 5 wt% of Cloisite 15A to vinylester. However, the same increased in the case of the addition of Cloisite Na, suggesting a positive influence of the organomodification on the moisture barrier properties. Although Fick's Law of Diffusion showed deviation from the experimental data in the nonlinear region of moisture absorption as a function of duration of exposure, the Langmuir Model was in better agreement with the experimental data in the entire range. (Cloisite 15A)/vinylester showed lower levels of microhardness deterioration due to moisture absorption than that of (Cloisite Na)/vinylester. J. VINYL ADDIT. TECHNOL.,

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Cement, fine aggregate, coarse aggregate and water are important constitutes of concrete that are obtained naturally. So we can replace new materials instead of natural sources such as M Sand, fly ash, Metakaolin, etc. Aim of this project is to study the strength properties of the concrete by partially replacing coarse aggregate by waste Cuddapah stones and using PPC-Fly ash based as cement. This thesis covers the properties of materials and mix proportions, preparation of concrete with waste Cuddapah stones, hardened state characteristics, and influence of various parameters on hardened state concrete and utilization of various materials in the structural members. Waste Cuddapah stones (WCS) were partially replaced as coarse aggregates in 20%, 40% and 60% respectively are casted and tested for 7 and 28 days. Fresh and hardened concrete properties are evaluated by workability test, compressive strength and split tensile test with a fixed water cement ratio 0.4. The test results were compared with the conventional concrete properties and show that there is an increase in strength of the concrete.

Concrete, an abundant material used in the construction industry uses huge amount of natural resources. These resources being exploited rapidly due to rapid growth in infrastructural construction resulted in the use of industrial wastes for concrete manufacture. The mechanical properties, durability properties are also important for the better understanding of the concrete to use it in the industry. Concrete of high grades such as M60 can be produced with fly ash, bottom ash and silica fume. In the present investigative study, Fly ash and silica fume combindly used as a cement replacement material at 15% and 10% respectively to that of cement. Bottom ash is used as a replacement to fine aggregate at the variable replacements of 0%, 10%, 20%, 30%, 40%& 50%. The compressive strength, non destructive tests such as rebound hammer test and ultrasonic pulse velocity test, durability tests like acid resistance, sorptivity were studied on the concrete. The observations showed that the concrete with constant replacements of fly ash and silica fume and 30% bottom ash gave the optimum results to use.