View
212
Download
0
Category
Tags:
Preview:
Citation preview
TEMPLATE DESIGN © 2007
www.PosterPresentations.com
Optimization of Concrete Composites Using CCBs as Additives
Joshua L. Baker
Rockdale Magnet School for Science and Technology
Introduction
Coal combustion byproducts have potential for use in concrete composites. If a mix ratio of these byproducts that allows for a strong, yet flexible end product can be achieved, it will be possible to apply the concept to other building materials once the composites’ environmental interactions can be investigated.
Experimental Design Diagram
Materials
• Hydraulic Wedge• Concrete Mixer• Plastic 4” x 8” Cylindrical Molds, 42• CEMEX® Portland Cement, 76.52 lbs.• Headwaters Class C Fly Ash, 6.94 lbs.• Natural Sand, 155.10 lbs.• Headwaters Bottom Ash, sieved, 12.96 lbs.• Stone, Granite, 252.87 lbs.• Water, 40.29 lbs.
Experimentation Procedures Experimentation Procedures (continued)
Data Analysis
Data Analysis (continued)
Discussion and Conclusions
Acknowledgements
OPTIONALLOGO HERE
OPTIONALLOGO HERE
Hypothesis• Research Hypothesis: If 25% of the standard
cementitious material or fine aggregate is respectively replaced with Class C fly ash or bottom ash, then the resulting composite will perform within a 20% margin of similarity to the control.
• Sub-hypothesis: Mix 2 (25% Class C fly ash, 75% Portland cement, sand, stone) will perform similarly to or better than the control mix.
Rationale
Successfully using CCBs as additives at a 25% replacement rate would greatly decrease negative human environmental impact stemming from dumping of these wastes in landfills and provide a strong, environmentally-responsible composite that can be adapted to new uses.
Each of the four concrete mixes was created using a concrete mixer.
A small amount of the first mix was poured into a unit weight container, and the unit weight was obtained. The cover was placed on the container, sealed, and the air content data was obtained. The unit weight container was cleaned out and the process was repeated with the remaining mixes.
A small amount of freshly-mixed concrete is poured into a mold and leveled off. The mold is then lifted off from the concrete, and the concrete is allowed to spread out. The slump, the distance the concrete spreads out is measured for each mix.
Concrete from each mix is poured into fourteen molds each, fifty-six in total, and then are left to set in room conditions for three days. The cylinders are then removed from their molds and placed into a curing room for another four days. Seven days after being poured in the molds, three samples from each group are placed in a hydraulic wedge, and the compressive strength and ultimate load data for each is obtained. The data and averages for each group are obtained in this way.
ANOVA Data:• Ultimate Load (Day 7): p = 0.005; 0.005 < 0.05; Null
hypothesis rejected• Compressive Strength (Day 7): p = 0.005; 0.005 < 0.05;
Null hypothesis rejected
• Based on the currently available data from experimentation and from data analysis, Mix 2 performed within the 20% margin of similarity to the control for its average compressive strength and ultimate load, thus rejecting the null hypothesis
• The data gathered for Mix 3 performed outside of this margin, supporting the null hypothesis
• More ultimate load and compressive strength data will be collected at the Day 90 curing point
RMSST:John Hendrix
Ernst Enterprises:Tony Dowdy
TEC Services:Steven Maloof and TechniciansBrian Wolfe
Future Research• Investigating the potential environmental effects the
composites may have in certain conditions• Determination of the toxicity of CCBs and their
flammability at different burn stages
Mix 1 (Control): 27.82 lbs. Portland Cement, 58.80 lbs. Natural Sand, 84.49 lbs. Stone
Mix 2: 6.94 lbs. Class C Fly Ash, 20.88 lbs. Portland Cement, 57.87 lbs. Natural Sand, 83.89 lbs. Stone
Mix 3: 27.52 lbs. Portland Cement, 12.96 lbs. Bottom Ash, 38.43 lbs. Natural Sand, 84.49 lbs. Stone
3 Trials 3 Trials 3 Trials
IV: Substituted Coal Combustion Byproduct
DV: Performance of Concrete Composite (Slump, Unit Weight/Density, Air Content, Water Content, Compressive Strength)
Constants: Brand and Type of Portland Cement, Class C Fly Ash, Bottom Ash, and Coarse Aggregate; Ambient Mixing Temperature; Ambient Curing Room Temperature and Moisture
Control 25% Class C Fly Ash 25% Bottom Ash136
138
140
142
144
146
148
150
152
Density
Target DensityActual Density
Mix Type
Den
sity
(lb/
f3)
Control 25% Class C Fly Ash 25% Bottom Ash0
0.5
1
1.5
2
2.5
Air Content
Mix Type
Air C
onte
nt (%
)
Control Fly Ash Bottom Ash0
10000
20000
30000
40000
50000
60000
70000
80000
90000
100000
54606.6666666667 55350
42946.6666666667
79870
93276.67
73530
Average Ultimate Load
Ultimate Load (lb) - Day 7Ultimate Load (lb) - Day 56
Ulti
mat
e Lo
ad (l
bs.)
Control Fly Ash Bottom Ash0
1000
2000
3000
4000
5000
6000
7000
8000
4343.33333333333 4403.33333333333
3416.66666666667
6356.67
7420
5850
Average Compressive Strength
Compressive Strength (psi) - Day 7Compressive Strength (psi) - Day 56
Com
pres
sive
Stre
ngth
(psi)
Recommended