Sub-Systems Design ReviewP14416

Concrete Arborloo Base

October 29, 2013

Team Intro

Member Role

Victoria Snell (ISE) Project Manager

Evan Burley (ME) Engineer

Joe Omilanowicz (ME) Engineer

Mac Keehfus (ME) Engineer

Anthony Deleo (ISE) Engineer

Agenda• Background• Functional Decomposition/Architecture• Updated Customer Requirements• Subsystems

– Geometry– Composition

• Compression Test Results– Features

• Cost/Trade-off Analysis• Engineering Requirements• Project Management Updates

• A latrine-like sanitation device designed to function over a small pit and to be moved to a new pit when filled

• Utilize compost by planting tree in used pit• Purpose to provide affordable sanitation in poor,

underdeveloped areas– Originally designed for use in Zimbabwe (Peter Morgan)

Arborloo

Functional Decomposition

Functional Architecture

Meeting with Francius Estimable (Johnny)

• Weight

• Price: ~25 USD = 1100 HTG

• Type of Cement is still unknown

• Prefers a DIY kit to educate locals

• Design should be simple

Updated Customer Requirements

2) Weight

• 25 dollars• Make it available to

all Haitians coming from different economic states

• Make it transportable through all environments

• Can be moved by 1-2 people comfortably

• Easy to make• Simple mold• Limited materials/

ingredients

1) Cost 2) Simpler the better

Meeting with Manitou• Self consolidating Concrete

– Self Leveling – Higher Slump– No Vibration– Chemical Needed (Water Reducer)

• More Efficient Mix Ratio– More Aggregate – Less Cement

• Specific Gravities• Finishing Tools• Use of Fibers

Geometry

• Shape• Thickness• Feasibility of

Molds

Theoretical Analysis• Maximum allowable

flexural and compressive strength for each mold design:

• Assume square slab• To make up for the

lack of stress concentrations due to the hole: Factor of Safety of 3

Θ

b: width into the board σcomp=σflex=

Theoretical Graph

0 50 1000

200

400

600

800

1000

1200

Theta (Degrees)

Str

engt

h (p

si)

Flexural Strength vs Theta

Shear Stress

0 50 1000

10

20

30

40

50

60

70

Theta (Degrees)

Str

ess

(psi

)

Compressive Stress vs Theta

Compressive Stress

Feasibility of Molds

• Wood– Plastic sheets

(release agent)– Reusable– Not as precise

• Metal• Plastic• Plastic injection methods• Foam

– Expensive (concrete canoe~$800)

– Very accurate– Trying to figure out

the release agent

Composition

• Aggregates• Bind properly• Provide strength• Reduce cost

• Cement Replacements

Mixtures• 6 different mixtures (each contained cement, course aggregates,

fine aggregates, and water)• Cement (ternary mix)

– Portland, slag, fly ash (improves strength, workability, and requires less water)

• Aggregates (all mixtures contained sand)– Course

• Coconut shells• Rubber• Limestone

– Fine• Sand• Plastic Beads• Styrofoam

Why?• Slag and fly ash improve strength

of concrete when combined with Portland

• Aggregates can be found in Haiti• Coconut shells

– considered trash/ in abundance

• Rubber– Need to figure out a way

to grind up tires

• Limestone/Sand– In abundance in Haiti

• Plastic Beads/Styrofoam– Could grind up plastic

water bottles

Cylinder Testing Procedure

• Slump test: General idea on mold capability as well as the proper amount of water

• After 7 days/28 days of curing– ASTM C39: radius= 4” height= 8” Cylinder is loaded

axially. Determines maximum compressive strength (psi)

Units (lbs) Mix 1 Mix 2 Mix 3 Mix 4 Mix 5 Mix 6 Mix 7 Mix 8 Mix 9

Cement 12.49 12.49 12.49 12.49 12.49 12.49 2.35 4.83 2.96

Slag 5.85 5.85 5.85 5.85 5.85 5.85 0.83 X 1.05

Flyash 4.82 4.82 4.82 4.82 4.82 4.82 0.65 X 0.82

Sand 1.50 1.50 1.50 1.50 1.50 1.50 6.95 8.87 8.87

Rubber 1.20 X X 1.20 X X 2.21 X X

Styrofoam 0.01 0.01 X X 0.01 X 0.04 X X

Plastic X X 0.68 0.68 X 0.68 X X X

Coconut X 1.20 1.20 X X X X 4.14 4.14

Limestone X X X X 1.77 1.77 X X X

Water 7.75 7.75 8.26 7.5 8 8.26 1.72 2.18 2.18

Glenium X X X X X X 10mL 8mL 8mL

Weight/cyl 6.45 6.77 6.70 6.73 6.88 7.08 4.53* 7.16* 7.32*

*weight measured before curing

Test Mixtures (lbs.)

Cylinder Plan• 70% Strength at 7 days• 28 day Accepted

Standard• Fibers add mild

Compression Strength• Limestone/Rubber/

Coconut/Shells/Sand/Stryofoam/Plastic

Results from 7 Day Cylinders

Trial 1 2 3 4 5 61 (7 days) 22.64 37.67 34.67 21.35 47.07 58.58

2 (28)3

Trial 1 2 3 4 5 61 (7 days) 1801.634 2997.683 2758.95 1698.98 3745.71 4661.65

2 (28) 0 0 0 0 0 03 0 0 0 0 0 0

Trial 1 2 3 4 5 61 (7 days) 270.24509 449.6525 413.843 254.847 561.857 699.247

2 (28) 0 0 0 0 0 03 0 0 0 0 0 0

Max Compressive Force For Mix (Kips)

Max Compressive Strength (psi)

Recorded

Mix Tensile Strength (psi, assume 15% compression)

Area of Test cylinder= 12.56637

A= π*r2 σ=F[lbf]/A[in2]

Mix performance

104

106

108

110

112

114

116

118

120

122

124

Mixture lb/ft^3

Mix 1 Mix 2 Mix 3 Mix 4 Mix 5 Mix 6

lb/ft

^3

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000Mixture Compressive Strength

Mix 1 Mix 2 Mix 3 Mix 4 Mix 5 Mix 6

Com

pres

sive

Stre

ss (p

si)

Improvements Moving Forward• Add more aggregates

– Used too much cement in first round of testing– Will reduce weight

• Make more viscous (less water)– Styrofoam floated to the top of cylinders– Use Glenium

• Use of finer aggregates– Sand is more dense than concrete– Higher strength with less voids

Features• Modular upgrades for additional cost• Prepare basic design to allow for add-ins

• Handles• Textures• Shelter connection points

Transportability

• Handles• Wheels• Rope Attachments

• Terrain is too rough for wheels• Anchor bolts require $ and drill

• Mold holes in sides for handles/hooks– Can this be done?

• Multi-functional attributes simplicity

$5.98

$2.80

$0.48

All require holes and

screws

$4.12

Shelter Interface• Holes?

– Consistent with transportability features– Pole connection

• Grooves?– Sheet metal

connection• Small size?

• Also reduces material and weight

• Depends on ground hole

Odor/Pest Reduction• Cheap, simple cover• What can be reused?• Simple hinge?

• Additional holes for toilet seat cover?

• Recommendation for household materials to use– Five gallon bucket

How to make it visually appealing and simple at the same time:

Material CostsMaterials Cost Weight (lb) Cost/lb

Rubber Mulch 10.98$ 19.8 0.55$ Coconut* -$ - -$ Limestone 10.00$ 2000 0.01$ Sand* -$ - -$ Styrofoam 14.99$ 2 7.50$ Plastic 7.99$ 2 4.00$ Cement* 6.28$ 94 0.07$ Slag 90.00$ 2000 0.05$ Fly Ash 70.00$ 2000 0.04$

*Reflects Cost in Haiti

Fly Ash/Slag?• Need to evaluate cost/strength trade-off

– Fly ash and slag are not produced in Haiti– Shipping costs are unknown– Currently testing mixes with and without flyash and

slag

Cost Breakdown

Weight Cost/lb Weight Cost Weight Cost Weight Cost Weight Cost1 Cylinder 4.2 0.28$ 1.6 0.06$ 2.0 0.09$ 0.2 0.11$ 0.2 -$ Arborloo 117.0 7.82$ 45.3 1.58$ 54.8 2.47$ 5.6 3.12$ 5.6 -$

Weight Cost Weight Cost Weight Cost Weight Cost1 Cylinder 0.6 0.00$ 0.5 -$ 0.003 0.02$ 0.2 0.92$ Arborloo 16.6 0.08$ 14.1 -$ 0.079 0.59$ 6.5 25.84$

Sand StyrofoamLimestone

Cement Fly Ash Slag Rubber Coconut Shells

Plastic Pellets

Summary of Results

ScoreMixtures Coarse Ag Fine Ag Total Cost Weight Compressive Tensile* Total Cost Weight Strength TotalMix 1 Rubber Styrofoam 15.58$ 181.41 1801.63 360.33 4 6 2 12Mix 2 Coconut Styrofoam 12.46$ 190.41 2997.68 599.54 6 4 4 14Mix 3 Coconut Plastic 37.71$ 188.44 2758.95 551.79 3 5 3 11Mix 4 Rubber Plastic 40.83$ 189.28 1698.98 339.80 1 3 1 5Mix 5 Limestone Styrofoam 12.54$ 193.50 3745.71 749.14 5 2 5 12Mix 6 Limestone Plastic 37.80$ 199.13 4661.65 932.33 2 1 6 9

Cylinder Strength (psi) Ranking

* Assume 20% of compression strength

PM Arborloo

Engineering Requirements– Purchase Cost

• Plastic expensive• Ranges from $12-$40• Target <$25

– Load it can support• Compression Results• Only 70% strength• Ranges from 1500 psi to 4600 psi• Target >2500 psi

– Ground Hole size Over design– Weight

• Average weight per/cylinder = 6.832 lbs.• Per/arborloo= 190.36 lbs.

Project Schedule: Past/Current

Project Schedule: Future

Budget Tracker

Item Store Price94 lb Portland Cement Home Depot $10.47

40" PVC Fencing Home Depot $9.97

48"x.25" Round Steel Rod Home Depot $9.26

Bird Netting Home Depot $14.47

.8 cu ft Rubber Mulch Home Depot $5.97

Plastic Sheeting Home Depot $10.98

Hardware Cloth Home Depot $9.22

Chicken Wire Home Depot $7.97

Bean Bag Filler Bed Bath and Beyond $14.99Cement Mixer Lowes $8.54Platic Beads Jo-Ann Fabrics $14.992 gallon Bags Target $8.18

Styrofoam Michael's $8.994”x8” Test Cylinders Forney LP $57.06

Total: $191.06

Updated Risk Assessment

Moving Forward• Refining concrete mixtures

– Aggregates for low cost compressive strength• Flexural testing

– Mold for test block– Finalize reinforcements

• Cost estimates– Availability in Haiti– Shipping costs

• Finalizing features– Continue to assess feasibility

• Divide team between mold and mixtures