Sivakumar Naganathan

Nanotechnology in Civil Engineering - A Review

Nanotechnology can be used for design and construction processes in many areas since nanotechnology generated products have many unique characteristics. These characteristics can significantly fix current construction problems, and may change the requirement and organization of the construction process. This paper reviews the basic concept of nanotechnology, different types of nanomaterial and their manufacturing process as well as the applications of nanotechnology in different fields such as concrete, pavement engineering, construction materials. Use of nanotechnology is found to offer high performing and efficient materials. Specific application areas include water and waste water treatment, construction materials etc. The use of nanotechnology in civil engineering is still in infancy stage. The production methods, pollutions caused to human health, manufacturing difficulties, performance are the issues to be addressed in order to use the nanotechnology in civil engineering.

Repair effectiveness of damaged RC beams with web opening using CFRP and steel plates

This paper presents an investigation conducted on repairing damaged Reinforced Concrete (RC) beams with a large rectangular web opening using externally bonded plates. Carbon Fiber Reinforced Polymer (CFRP) and steel plates were used as repair materials with two types of configuration hexagonal and rectangular for each material. The beams contain a rectangular web opening at one of the shear spans. The externally bonded CFRP sheet and steel plate were found to be effective in repairing RC beams with a large rectangular web opening. The results showed that CFRP plates perform better than steel plates and that the rectangular configuration is better than the hexagonal one.

Repair effectiveness of CFRP and steel plates in RC beams with web opening: effect of plate thickness

The effect of steel plate thickness on the repair effectiveness of RC beam is presented in this paper. A total of four beams were tested, one beam repaired by CFRP with a thickness of 1.2 mm and used as a control beam, and three beams repaired by a steel plate. Steel plates with a thickness of 2 mm, 3 mm, and 4 mm were used in repairing the beams. The maximum loadcarrying capacity, deflection at mid span and edge of the opening, strain in steel bars, strain in externally bonded plates, crack patterns, and failure modes were observed on each beam. The externally bonded CFRP sheet and steel plates were found to be effective in the repairing of RC beams with large rectangular web opening. The results show that increasing steel plate thickness has little effect on the maximum load capacity. The CFRP plate is more effective than steel plate in increasing the load capacity of beams.

Experimental investigation of bond characteristics between CFRP and steel under tensile loads

Rehabilitation of damaged infrastructure has become a priority in recent years as an alternative to the daunting costs of rebuilding structures. Traditional strengthening methods have drawbacks, many of which can be overcome through the use of carbon fiber reinforced polymer CFRP. Considerable research has been directed to investigate the effectiveness of bond length and strength between CFRP and steel. Research results indicated that significant increase in strength due to CFRP strengthening can be obtained. Nevertheless, in-depth understanding of debonding failures along the steel-epoxy interface is still a challenging issue. This paper presents three different experimental models with new surface preparation to increase bond strength and control debonding failure between CFRP fabrics and steel. The experimental results indicated that debonding failure can be controlled to some extent with proposed surface preparation technology.

Use of Wastes in Developing Mortar – A Review

This paper is a literature review about the use of wastes in masonry mortar. Wastes such as wood waste ash, municipal solid waste, ground waste seashells, glass waste, fly ash, corn cob ash and palm oil fuel ash are used to replace cement as the binding material. Wastes of Cathode Ray Tube (CRTs) glass, plastic waste, construction demolition wastes, foundry sand and quarry dust are used as a replacement for fine aggregates. Additives such as recycled copper tailings and animal proteins also improve the properties of masonry mortar. It is learnt that certain percentages of wastes can be used as substitutes for binding materials and fine aggregates and therefore the ideal amount of waste can be determined.

Green bricks from waste

This paper presents the findings on an investigation done on the use of Quarry dust, Fly ash and Billet scale in developing bricks. Bricks were made with various proportions of those materials and cement. Tests for fresh density, compressive strength, and water absorption were conducted. The compressive strength of bricks ranged from (7.2-26.3) MPa, the water absorption fell in range between (13-14.26) %. The optimum ratio of Fly ash and Billet scale is 1:1. It is shown that bricks with enhanced properties can be developed using these industrial wastes.