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Here are some topics for research offered by Dr J D Bapat:

(a) Combustion of rice husk under controlled conditions to produce pozzolanic rice husk ash

(b) Concrete with binary mixtures of cement and rice husk ash 

(b) Concrete with ternary blends of cement, fly ash, ground granulated blast furnace slag and rice husk ash

(c) Rheology of concrete with different compositions and its relation with fresh concrete properties

(d) Other industrial wastes as concrete admixtures

(e) Long term studies on concrete durability

(f) Using pond ash in road construction

(g) Bacterial concrete

PORTLAND SLAG CEMENT/GGBS FOR DURABLE STRUCTURES UNDER MARINE CONDITIONS

 Dr J D Bapat

Abstract :  The  corrosion of reinforcement is the major factor responsible for distress and deterioration of concrete structures under marine conditions. The ingress of chlorides is the principal cause of corrosion; carbonation and sulphate attack are the main factors assisting it. The ground granulated blast furnace slag (GGBS) is a mineral admixture and can be added to the ordinary Portland cement (OPC) , in the cement plant, and  marketed as Portland slag cement (PSC) or as an admixture to cement concrete, at the site. The paper reviews the impact of all the three deteriorating factors  on the concrete , considering corrosion as principal factor , and the contribution of mineral admixture like GGBS towards improving its durability, under marine conditions. The carbonation depends upon the relative humidity of the environment, permeability of the concrete and the curing conditions. The data on the carbonation of structures available through a number of long term researches carried out world over, on different types of cements, have established that there is no connection between the degree of carbonation and the type of cement. The sodium and the magnesium sulphate, both deleterious to the concrete, are obtained under marine conditions along with high content of chlorides. The deterioration caused due to magnesium sulphate is mainly seen in terms of the reduction in the compressive strength and that due to sodium sulphate in terms of expansion, in the concrete structures. The long term experiments carried out under actual sea water conditions reveal that the concrete with PSC/GGBS has better resistance towards sulphate attack. The refinement of pore structure and the chloride binding capacity of concrete with PSC/GGBS are the principal causes behind the reduced permeability, higher electrical resistance and the resultant higher corrosion resistance and the durability of such concrete under marine conditions.  

Key words :  cement, concrete, construction, durability , service life , slag cement, blended cements , ground granulated blast furnace slag (GGBS), reinforcement corrosion , chloride attack, sulphate attack , marine structures , carbonation

Topics for further research: Using other slags as building materials, developing high volume slag concrete

Read technical article: Portland slag cement / ggbs for durable structures under marine conditions