Date of Award

Spring 5-14-2016

Level of Access

Campus-Only Thesis

Degree Name

Master of Science in Civil Engineering (MSCE)

Department

Civil Engineering

Advisor

Eric Landis

Second Committee Member

Todd Rushing

Third Committee Member

Edwin Nagy

Abstract

Structural lightweight aggregate concrete is not a new concept; however, pushing past the traditional methods of including normal weight fines while still receiving the strength and durability desired is a unique challenge especially at a 1680 kg/m3 fresh density. The lightweight aggregate concrete produced at this density was done so using 0-9.5mm expanded shale aggregate, 363 kg of cementitious material containing 50% type II Portland cement, 45% slag and 5% silica fume, and various admixtures, including Darex II, an air entraining admixture to achieve 8% air content.

A study was performed that compared compressive strengths and bulk electrical resistivities for varying levels of slag and silica fume to attempt to pin-point an optimal ratio. Levels of slag used were 15, 30, and 45% of total cementitious material, and for each slag level three levels of silica fume were used (3, 5, and 7% of total cementitious material). From this study the combination of 45% slag and 5% silica fume usage was derived and chosen to move forward with additional testing.

Additional testing performed included the following: quality control fresh concrete tests (slump, unit weight, and air content), short-term creep, free and restrained shrinkage, freeze-thaw, hardened air void, modulus of elasticity, modulus of rupture, equilibrium density, and underwater abrasion. Based on the tests completed, the lightweight aggregate concrete mixture containing 45% slag, 5% silica fume, and 50% type II Portland cement for cementitious materials to be adequate for use in marine environment applications.

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