Study on Strength Characteristics of High Strength Rice Husk Ash Concrete

AbstractThe objective of the study is to investigate the mechanical properties of high strength concrete with different replacement levels of ordinary Portland cement by Rice Husk Ash. The standard cubes (150mmX150mmX150mm), cylinders (150mmdiaX300mm height) and prisms (100mmX100mmX500mm) were caste. In all 144 specimens with M40 and M50 grade mix cases were caste and tested. The strength effect of High-strength concrete of various amounts of replacement of cement viz., 0%, 5%, 10%, 15% with Rice Husk Ash of both the grades were compared with that of the high-strength concrete with out Rice Husk Ash. The compressive strength at 7, 28 and 56 days have been obtained. The results of the mechanical properties of the rice husk ash at 28 days have shown quite encouraging and interesting results. The optimum replacement of rice husk ash found to be 10% in both the grades of the concrete

Substantiation of concrete core rational parameters for bending composite structures

In order to provide bending structures rationalization for reducing the materials consumption, labor and power inputs, construction or renovation terms, the authors considered the possibility of utilizing the structures with external steel sheet reinforcement and concrete layer made from fibers of different types. Experimental researches of various authors, both domestic and overseas, have been analyzed during the preliminary investigations. As a result, the steel and basalt fibers were selected for further inquiry, proved their rational sizes, percentage to concrete mass in structures worked under thermal and force impacts. It was developed the algorithm and software, helps to determine the stress-strain state and carrying capacity of composite floor slabs with different end and load conditions. It was concluded the necessity of physical-mechanical and thermal physic properties clarification of heated fibrous concrete. The experiment planning was performed to obtain the temperature dependences of strength and modulus of deformation, thermal conductivity and specific heat capacity of fibrous concrete mix

Mechanical properties of steel fiber reinforced recycled aggregate concrete

This study experimentally investigates the mechanical properties of steel fiber reinforced recycled aggregate concrete (SFRRAC). The smaller strength and ductility of recycled aggregate concrete (RAC), compared to those of natural aggregate concrete (NAC), have restricted its use to mainly non‐structural applications in the construction industry. Such limitations in the mechanical behavior of RAC can be overcome by adding industrial steel fiber (SF). In this study, the split‐tensile strength, the compressive strength, the toughness under compression and the elastic modulus for 25 SFRRAC mixes are experimentally investigated. These 25 mixes were prepared from combinations of five different volume fractions of SF, 0, 0.3, 0.5, 0.7 and 1.0% and five different replacement proportions of natural aggregates (NA) by recycled aggregate (RA), 0, 30, 50, 70 and 100%. From experiments, it was observed that the split‐tensile strength, the compressive strength and the elastic modulus of SFRRAC mixes decreased with RA content; the split‐tensile strength and the toughness under compression increased with SF content. However, there was no clear correlation observed between the SF content and the compressive strength or the elastic modulus. Regression models were established based on the RA and SF contents in the SFRRAC mixes to predict their split‐tensile strength, compressive strength and elastic modulus