Evaluation of Silica-Based Materials for Use in Portland Cement Concrete

Project Details









Christopher Ferraro, Jerry Paris, Kyle Riding, Timothy Townsend, Eduard Tora Bueno


Florida Department of Transportation


Ash content, Evaluation, Paving materials, Portland cement concrete, Silicates




Project description

The purpose of this research was to evaluate the mechanical performance and long-term durability of concrete containing alternative supplementary cementitious materials (ASCM) available in the state of Florida that were identified in a previous research project (FDOT BDV-31-977-06) as warranting further investigation. The ASCM chosen were two types of Florida sugarcane bagasse ash, ground sand, ground recycled container glass, and ground volcanic rock, all of which were identified as potential substitutes to class F fly ash for future use in concrete. Both Type I/II and Type IL cements were included in the investigation to account for the increasing use of IL cements in industry. Mixes containing Class F fly ash, Class C fly ash, and silica fume were used for comparison and Class C fly ash was used for all ternary mixes. Raw material testing included elemental and mineralogical compositions determined by x-ray fluorescence (XRF) and x-ray diffraction (XRD), chloride content, particle size distribution employing laser particle size analysis, apparent specific gravity determined with a helium pycnometer, specific heat capacity using a differential scanning calorimeter (DSC), and quantity and rate of heat generation of the cementitious materials found by isothermal calorimetry. Fresh properties of mortars and concretes examined included mortar flow, time of set, slump, temperature, density, and air content. Hardened mechanical properties measured included compressive strength, splitting tensile strength, flexural strength, modulus of elasticity, and coefficient of thermal expansion. Durability testing included surface and bulk resistivity, resistance to alkali-silica reaction and resistance to sulfate attack. Ground glass produced the most promising results of all the ASCM that were evaluated. Sugarcane bagasse ash performed well in some regards but has a variety of barriers towards implementation. Volcanic rock and ground sand produced results indicating that both are likely filler materials with little pozzolanic reactivity.