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Abstract

Three types of bricks were selected for testing properties of brick aggregates and brick aggregate concrete. W/C ratios from 0.63 to 0.24 were investigated. The mix design method given in 'Design of Normal Concrete Mixes' specified by the Department of Environment U K. was followed initially. Permeability testing for concrete with brick aggregates was carried out by the help of ISAT, capillary rise test and Voltage driven chloride diffusion test. Tests for evaluation of frost resistance of concrete with brick aggregates were carried out along with sulphate resistance tests on concrete with brick aggregates. Investigations on high strength concrete with brick aggregates were also made along with tests on mixes with Thames Valley gravel replaced partially by brick aggregates.

Mixes with brick aggregates were generally observed to be less workable as compared to mixes with gravel. Performance of concrete with brick aggregates depends basically on the crushing strength and absorption of bricks from which the aggregates are obtained. Brick aggregate concrete developed satisfactory cube compressive strength. Cylinder strength was observed to be about 10% lower, as compared to concrete with gravel. Split cylinder tensile strength varied from 18% lower to 20% higher whereas flexural strength was observed to vary from 13% lower to 22% higher than concrete with gravel. Strains were observed to be 10 to 83% higher at failure, for brick aggregate concrete. Static modulus of elasticity was found to be 28 to 59% lower whereas dynamic modulus was also observed to be lower by 13 to 2 6% as compared to concrete with gravel. Densities of concrete with brick aggregates were lower by 5 to 13% than concrete with gravel. Coefficient of thermal expansion varied from 35% lower to 5% higher than the values of normal concrete. Concrete with brick aggregate was found to have the values of surface absorption ranging from about the same to twice than for concrete with gravel aggregate. Chloride ion diffusion rates also varied from two to three times the amount for concrete with gravel.

Concrete with normal construction brick aggregates was observed to be highly frost susceptible whereas concrete with sand lime brick aggregate performed better and concrete with engineering brick aggregate performed in a similar manner to concrete with gravel aggregate.

In the sulphate resistance test, the reduction in dynamic modulus for concrete with gravel was rapid as compared to a gradual reduction for concrete with brick aggregates. High strength concretes with engineering brick aggregate developed satisfactory strengths up to 80N/mm2. Concrete with brick aggregates mixed with gravel showed reduced frost resistance, 37% reduction in static modulus and 23% reduction in dynamic modulus of elasticity as compared to concrete with gravel aggregate.

Publication Type:	Thesis (Doctoral)
Subjects:	T Technology > TA Engineering (General). Civil engineering (General)
Departments:	School of Science & Technology > School of Science & Technology Doctoral Theses Doctoral Theses School of Science & Technology > Engineering

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