K. S. Satyanarayanan

Augmentation of mechanical and bond strength of coconut shell concrete using quarry dust

The properties of concrete using quarry dust (QD) as fine aggregate and coconut shell (CS) as coarse aggregate were examined in this investigation. Workability, density of concrete, compressive, flexural, splitting tensile strengths, impact resistance and bond strength were considered and evaluated with the theoretical values as recommended by IS 456 and BS 8110 standards. For comparison, both conventional and CS concrete mixes are selected with sand and QD have been considered to study. The bond strength was determined as per IS 2770 (Part-I 1987) and ASTM C 234. This study proves that the use of QD in place of sand augmented the mechanical and bond properties of both CSs concrete and conventional concrete as well.

High Energy Absorbent Sustainable Concrete Element From Used Tin Cans

Large quantities of solid wastes are being generated worldwide which lead to environmental concerns. One such major component is tin cans. Utilization of tin cans wastes in making building construction materials can reduce the magnitude of many associated problems. “Energy Block” is a type of block which has high energy absorption when kept under load. It is mainly composed of cement, sand, fibers, and tin cans. This paper shows the energy block is an environment friendly and lightweight building block from cement mortar, waste tin cans and fibers, without the use of coarse aggregate providing high energy absorption to the concrete. The paper concludes the results of laboratory tests and the actual behavior and performance of such building materials in practical application providing lightweight and the usage of tin cans can be economical for conservation of environment.

Confining effect by hot rolled steel and cold formed steel on coconut shell concrete with quarry dust

Properties of concrete using quarry dust as fine aggregate and coconut shell as coarse aggregate were examined. Hot rolled and cold formed steel were used as an external confinement on both conventional concrete and coconut shell concrete mixes. Workability, density of concrete, compressive, flexural and impact resistance were considered and evaluated. Uses of quarry dust in place of sand reduce workability and increase density of concretes. In case of without confinement, the compressive strength variation between cubes strength and cylinders strengths are traditional and it is not if it is confined. Flexural specimen with confinement does not fail and stands enough without any sign of failure in case of hot rolled steel. However, in case of cold formed steel, flexural specimen with confinement enhances approximately nine times of the flexural specimen without confinement and stands enough with ductile manner. Hot rolled and cold formed steel confinement effect is not allowing the impact specimen to form crack and in turn not allows failing the specimen. This study proves that the use of quarry dust in place of sand augmented the mechanical properties of both coconut shells concrete and conventional concrete as well. Confinement effect improves promptly the mechanical properties of concretes.

Effect of Masonry Infill Structure with Openings during Progressive Collapse by Removing a Middle Column

Background/Objectives: Progressive collapse occurs when primary structural element fails due to many reasons such as impact, bomb blast, earthquake, abnormal loading etc., resulting in the failure of adjoining structural elements, which in turn causes partial or total collapse of the structure consequently. It is studied widely in Reinforced Concrete (RC) framed structure. Methods/Statistical Analysis: The present study investigates the comparative behaviour of four bay, five storey RC bare frame, infilled frame and infilled frame with openings and to assess the effect of infill to resist the progressive collapse. A linear static analysis is carried out using finite element software using SAP 2000 and maximum moment (M), shear force (V), axial force (P), deflection (U) for both beams and columns generated before and after middle column removal are studied and compared. Findings: There is an average of 30% and 34% decrease in moments for infilled frames when compared to a bare frame. The percentage of decrease in moments increases to an average of 71% when the column is removed. Similarly, the deflection for infilled frames decreases by35% when compared with bare frame and only 17% increase when infills are provided with openings on removal of column there is average of 88% decrease in deflection for infilled frames when compared with bare frame. It shows that the presence of infilled frames will delay the progressive collapse when compared to bare frames. Application/Improvements: The study can be extended to the non-linear range and also to find its dynamic response.