Study of Durability and Mechanical Properties of No-Aggregate Concrete

Abstract

Construction industry has a very large carbon foot print on the environment. The manufacturing of cement releases large amount of carbon-dioxide in the environment. The thermal power stations also release carbon-dioxide along with a by-product called as y ash. The disposal of y ash is a tough job to perform because of its fine nature. Fly ash has approximately similar char- acteristics like cement. Generally, during manufacturing of concrete, 20-30% of y ash is used as a replacement of cement. One of the alternatives to produce more environmental friendly concrete is to replace the amount of Portland cement in concrete with by-product materials such as y ash. A new type of material comes into picture over here termed as No-Aggregate Concrete which has been innovated by Dr. N Bhanumathidas and Mr. N Kalidas [1][2] . It is generally defined as the concrete without any type of aggregates. In this concrete, 80% of cementitious material is contributed by

y ash and remaining 20% by cement. This type of concrete has excellent

ow characteristics. It ows readily in any type of formwork without any problems which are generally observed during the placement of conventional concrete. It is also cheap as compared to control concrete because none of the type of aggregates are used and also the y ash which contributes to a large portion of the concrete is about 82% cheaper than cement. The main aim of the study is to replace bulk of cement with y ash, reduce cost of concrete by removing aggregates and increase strength of concrete. Experimental work in this major project comprises preliminary investigation on No-Aggregate Concrete. The most important characteristics to be studied are compressive strength, exure strength, split tensile strength, modulus of elasticity, bond strength, chloride attack, sulphate attack, acid attack and corrosion resistance. Results are compared for No-Aggregate Concrete and Control Concrete made with same cement content used in No-Aggregate Con- crete. The results related to mechanical and durability properties for both con- crete mixes have suggested adequate performance of No-Aggregate concrete as compared to control concrete. The results show significant improvement in behaviour of No-aggregate concrete as compared to that of control con- crete for various mechanical properties attempted in the present investiga- tion such as compressive strength, exure strength, split tensile strength and modulus of elasticity, respectively except the bond strength. Test re- sults have indicated that No-Aggregate concrete posses good durability re- sistance. Acid resistance test results shows very low mass loss and strength loss of No-Aggregate concrete after various exposure period compared to con- trol concrete. Sulphate and chloride resistance also indicate good resistance of No-Aggregate concrete with no significant change. Further the investi- gation about corrosion resistance demonstrates that No-Aggregate concrete consumes more time to develop crack as compared to that of control con- crete. Half-cell potentiometer readings of No-Aggregate concrete are lesser on negative than control concrete. Thus investigation suggests No-Aggregate concrete is a good alternative as a construction material from strength considerations. Furthermore investi- gation is to be done related to the durability properties of No-Aggregate concrete. Results of present investigations are definitely suggest that No- Aggregate concrete could be one of the very efficient material to be used as a structural concrete.