20 Time Final Post

My 20 Time project was about converting regular concrete into pervious concrete. I was successful in making a slab of concrete porous by spraying it with chemicals. Gypsum and vinegar were the two chemicals that worked and I have submitted my project to Google Science Fair. Over the summer, I will continue to work on my project by finding the most effective mixtures of gypsum and vinegar for use on concrete. I will also test the structural stability of treated concrete blocks.

Gypsum I tested on the concrete in an ~1/5 solution in water

The TED Talk I gave in class about my project

I would say my talk went quite well. Although I stumbled a lot at the start, once I got on track, my speaking got smoother and I was able to articulate my thoughts in a way the audience could understand. I thought I would need my notes, but I ended up just using the images as cues. That being said, I was still very nervous beforehand because I had only written the script the night before. I also had no words in my slideshow, so there were no hints to read off of without looking down at my notes.

Even though I was more nervous before this presentation than before my "What on Earth Evolved?" Presentation, I felt this one looked more professional overall. This is because I had more true passion for what I was talking about, allowing me to walk around and look relaxed. However, I may have been unclear in some parts because during the questions, some people were asking me things that I thought I had answered while talking. Overall, this was a slight improvement from my Tiktaalik presentation, but a definite improvement from my public speaking skills at the start of the year.

20 Time Individual Reflection

For my 20 Time project, I challenged myself to develop a chemical which can make regular concrete pervious. My goals were realistic and although I did stray from my timeline, I still finished. My plan was to spread the experiment over 6 weeks, but I ended up buying my materials just 2 weeks before the deadline. As soon as I got my materials though, I created a plan to make sure the testing gets done before the project is due.

I think my plan was a success. Out of the 13 chemicals I tested, about 6 worked well. However, I only chose to retest 3 because the others were unrealistic to use in the real world or weren't very efficient. When retesting, I put a metal can (open on both sides) and sealed the base with wax. I then poured water into the can so it's resting on the concrete. Some water did drip through the sealant, but I watched the apparatus to make sure water wasn't cheating by entering the bucket from the sides rather than from through the concrete. One of the chemicals, gyspum dissolved in water, yielded 55ml of water. Considering that some of the 250ml had dripped outside of the bucket, the treated concrete had about a 30% efficiency.

I came into this project expecting basically nothing. I knew my idea was great, but I doubted that it would work. But when I got positive results, I realized that I might be on to something. I decided to team up with a friend from my old school and submit the project to Google Science Fair. The project is due in a week, and we are almost done with our written essays. If I have free time, I might put together a video with all the images and footage I captured while experimenting. In conclusion, I feel that my 20 Time project was really fun as well as successful, but I am still at the tip of the iceberg. Although the due date for Google Science Fair is coming up soon, I will spend some time this summer developing concoctions of gypsum and vinegar (my highest performing chemicals) and testing them.

Testing!

I finally started testing the chemicals last week. Yay! I know I'm about a month off schedule and that the project is due in barely a week, but I made a plan last week. I've stayed on track for the past 6 days. Here is what the past 6 days have looked like:

Chemical	Spray/Soak Time	Test Time	Amount of Chemical	Amount of Water Sprayed	Amount of Water Collected	Notes	Retest?
Control (nothing)	9pm 4/26-7pm 4/27	7:30-8:00	N/A	250ml	0
Sakrete	9pm 4/26-7pm 4/27	7:25-7:55	500ml	250ml	0	Edges crumbly and green on second day
Gypsum	9pm 4/26-7pm 4/27	8:04-8:34	250ml (60ml gypsum+250ml H2O)	250ml	~30ml (retest needed)	Retest needed	Yes
Alcohol and Burn	7pm 4/28 (but n/a)	9:41-10:11	500ml	250ml	~20ml	250ml spray then burn; 250ml spray while burning. Surface hot	No; unrealistic
Vinegar	7:15pm 4/28-9pm 4/29	9:13-9:43	250ml	250ml	~40ml	Bubbling a little after sprayed chemical	Yes
Ammonia	6:30pm 4/28-9pm 4/29	9:09-9:39	250ml	250ml	0	Poured instead of sprayed chemical
Hydrochloric Acid	3:45pm 4/30-4pm 5/1	4:33-5:03	250ml	250ml	~40ml	Foamed up yellow/green when poured chemical; Poured because of danger	No; unrealistic
Bleach	3:30pm 4/30-4pm 5/1	3:59-4:29	250ml	250ml	50ml		Yes; a lot of H20
Hydrogen Peroxide	3:20pm 4/30-4pm 5/1	3:56-4:26	250ml	250ml	~10ml	Greenish square formed in center; Fizzing/bubbles when spraying chemical	No; not enough
Sulfuric acid	3:20pm 5/2-4pm 5/3	4:20-4:50	250ml	250ml	15ml	Bubbling/fizzing when sprayed chemical	No; unrealistic
Coke	3:30pm 5/2-4pm 5/3	4:54-5:24	250ml	250ml	20ml
Calcium Chloride	3:15pm 5/2-4pm 5/3	4:23-4:53	250ml	250ml	10ml	White residue on concrete after 24 hours	No; unrealistic
Seawater	6pm 5/4-4:30pm 5/5	4:33-5:03	250ml	250ml	0	Salt residue on tub after 24 hours
Dry Ice	6pm 5/4-4:30pm 5/5	4:30-5:00	5 lb	250ml	0	All dry ice gone after 24 hours

Basically, I spray the concrete with 250ml of chemical one day and let it soak until the next day afternoon. After those ~24 hours, I put the slab on top of a bucket and spray it with 250ml of water. I let the water sit for 30 minutes, then measure how much has dripped through the concrete and into the bucket below.

There may be a few flaws in this experiment, including water seeping into the bucket from the edges of the slab and differences in amount of water actually landing on the concrete. To remedy this I will be retesting some of the highest performing materials. Here are my retest results:

Chemical	Spray/Soak Time	Test Time	Amount of Chemical	Amount of Water Poured	Amount of Water Collected	Notes
Gypsum	5pm 5/6-6pm 5/7	6:13-6:43	250ml (60ml gyspum)	250ml	55ml	Used crayon wax as sealant; no visible drip into bucket from sides
Vinegar	5pm 5/6-6pm 5/7	6:22-6:52	250ml	250ml	30ml	Used candle wax as sealant; no visible drip into bucket from sides
Bleach	5pm 5/6-6pm 5/7	6:59-7:29	250ml	250ml	50ml	Used candle wax as sealant; no visible drip into bucket from sides

Buying the Stuff

I have successfully purchased everything*! I got the pavers, spray bottles, sakrete dissolver, calcium chloride, gypsum, flammable alcohol, ammonia, and hydrochloric acid from Home Depot. I also just bought some 3% Hydrogen Peroxide from Walgreens because they don't have that at Home Depot. I already have liquid chlorine bleach and vinegar. I will buy some coca-cola from 7-11 when I need it, and Natalia Denenberg is going to Monterey Bay for her 20 Time so she will fill up a bottle of seawater for me there.

*I emailed San Jose Scientific about the Sulfuric and Nitric acid and here is what they said-

Thank you for your inquiry. We do carry both of those items in our Retail store we currently only sell these as Pints & Gallons. Though we do have Sulfuric Acid in a 1.0N solution in a liter $24.95.

Sulfuric Acid - Pint 95-98% $44.95, Gallon 96% $61.95

Nitric Acid - Pint 68-70% $44.95, Gallon 69% $53.95

I'm quite sure both sulfuric and nitric acid will just completely ruin the concrete without making it pervious or anything. So rather than spending 90 bucks for 2 pints of chemical which will probably do the exact same thing, I will be ditching the nitric acid and only purchasing sulfuric acid.

I don't exactly need a gallon though, because that's more than 7 times the 500ml of chemical I need. But I need more than a pint because that is about 30ml less than the 500ml I need. And because I can't just ask them to fill up a 500ml cup or something, it looks like I will just be choosing between 473ml of 97% sulfuric acid or 1000ml of 5% (see below for how I calculated) sulfuric acid. 

After much deliberation, I have decided to spend $25 on the 5% sulfuric acid. Although it has a concentration that is suboptimal, handling 97% sulfuric acid is extremely dangerous and I don't want to risk it. In addition, the 5% solution has double the volume I need, and there are ways to purify sulfuric acid by boiling solutions of lower concentrations. Having an extra 500ml to play around with may allow me to synthesize some purer sulfuric acid and use that on the concrete slab that would have originally be used for nitric acid. So now slab 2 has 5% sulfuric acid and slab 11 has sulfuric acid of a higher concentration that I will make.

How I calculated the percentage concentration of the 1.0N Sulfuric acid solution-

1.0N H2SO4 = 0.5M H2SO4

Molar mass of H2SO4 = 98.079 g/mol

0.5M x 98.079grams/mol = 49.0395grams

Mass of 1 liter of water = 1000.028 grams

49.0395/1000.028 = 0.04903812693

0.04903812693 x 100 = 4.903812693

~4.9% Sulfuric acid solution

Finding a place to purchase dry ice was annoying. I first searched up "dry ice" on google maps to find stores that might sell them. After digging through tons of industrial gas vendor websites, I landed on a wikihow page about how to buy dry ice. It said that most grocery stores including Safeway carried dry ice. I actually needed dry ice in 6th grade but never got it even after going from store to store for an entire day. But I decided to try calling up the nearest Safeway. They said that although they don't carry dry ice, a Safeway on El Camino does. I called the El Camino location up and was quite surprised that they actually do carry dry ice. Unfortunately, they are out of stock till Thursday, which is fine because I won't actually need it until Friday evening.

If I have 500ml of chemical, that means there will be a 0.2in. layer above each sq. inch of concrete if slab is 1 sq ft.

Already ordered

Already have

Have plan to get but haven’t gotten yet

No idea how to get

Concrete Pavers

http://www.homedepot.com/p/12-in-x-12-in-Pewter-Concrete-Step-Stone-71200/100333077

Spray Bottles

http://www.homedepot.com/p/Continental-24-oz-Sprayer-and-Bottle-3-per-Pack-CMC9223SP/205907081

1. Sakrete Dissolver

http://www.homedepot.com/p/SAKRETE-22-oz-Concrete-Mortar-Dissolver-65510207/204675360?cm_mmc=Shopping%7cTHD%7cG%7c0%7cG-BASE-PLA-D22-Concrete%7c

2. Sulfuric Acid

https://www.sanjosescientific.com/products/hazardous-chemicals

(I will pick it up from the store)

3. Carbonated Water Liquid

Use regular american coca-cola

4. Calcium Chloride

http://www.homedepot.com/p/Snow-Joe-10-lb-Jug-Calcium-Chloride-Crystals-Ice-Melter-MELT10CC-J/205668956

5. Gypsum dissolved in water

http://www.homedepot.com/p/Arizona-s-Best-0-5-cu-ft-Gypsum-433675/202311920

6. Seawater (or water with high salt concentration)

Natalia will give from Monterey Bay

7. Oil and then light on fire (not sure whether this will work and I might not actually do this)

Ethanol- http://www.homedepot.com/p/Klean-Strip-1-qt-Green-Denatured-Alcohol-QKGA75003/202249513

8. Vinegar

Already have

9. Ammonia

http://www.homedepot.com/p/HDX-64-oz-Lemon-Ammonia-19718615031/202676388

10. Hydrochloric acid

http://www.homedepot.com/p/Klean-Strip-1-gal-Green-Muriatic-Acid-GKGM75006/202690263

11. Nitric acid

https://www.sanjosescientific.com/products/hazardous-chemicals

Sulfuric acid of a higher concentration that I will synthesize from the 5% by boiling

http://www.amazingrust.com/Experiments/how_to/Concentrating_H2SO4.html

http://chemistry.about.com/od/makechemicalsyourself/a/How-To-Make-Sulfuric-Acid-At-Home.htm

12. Dry Ice (I will dump it in the bucket underneath so CO2 goes up)

785 East El Camino Real. Sunnyvale, CA 94087

13. Liquid Chlorine Bleach

Already have

14. Hydrogen Peroxide

http://www.walgreens.com/store/c/walgreens-hydrogen-peroxide-3-first-aid-antiseptic/ID=prod6056574-product

15. Nothing

While purchasing these products and finding places to purchase these products, I have learned more about molarity and chemical calculations, how useful home depot is, and just general stuff about chemistry. While writing this blog post, my ideas have morphed so much and I think that's great. Coming into this blog post, I thought I just wouldn't be using sulfuric acid, nitric acid, or dry ice. Now I have an updated plan that still utilizes all 15 slabs.

Finishing Finding Chemicals to Test

I have learned more about how tough chemical research is. I thought I would just have to find a few chemicals and then look for closely related ones on the wikipedia page. Unfortunately, I couldn't find many chemicals in this way and had to be much more creative. I am quite glad that I was able to find all 15 chemicals and didn't have to resort to choosing random things that I am sure won't work. Although I haven't had any setbacks, I still need to find places to buy some of the chemicals. The next step is to buy all of the stuff and start with my experiment.

Here are the rest of the chemicals I will be using (the first 5 are here):

6. Seawater (or water with high salt concentration)
Causes efflorescence or corrosion
7. Oil and then light on fire (not sure whether this will work and I might not actually do this)
Maybe the fire will do something?
8. Vinegart
Weak acid; I doubt it will do much
9. Ammonia
Base; I doubt it will do much
10. Hydrochloric acid
Generally strong acid
11. Nitric acid
Strong acid and oxidizing agent
12. Dry Ice (I will dump it in the bucket underneath so CO2 goes up)
The carbon dioxide may cause carbonatation
13. Liquid Chlorine Bleach
Might have some effect on the concrete
14. Hydrogen Peroxide
Strong oxidizing agent
15. Nothing
This is the control to see how much water naturally leaks through

Finding Chemicals to Test

Over the past couple weeks, I have been able to identify 5 substances that may cause porosity in concrete. I also found some concrete pavers and spray bottles on homedepot.com that are quite cheap but seem of good quality. I still have 9 substances to identify, which I expect to be completed by Monday (3/21). After that, I will get the entire set up prepared and start experimenting on the following Friday.

While researching the potential liquids, I realized how much searching and digging it takes to find substances that have a chance of changing the concrete. I learned that I like these kinds of research projects, but I get sidetracked easily. For example, I was looking at what effects carbonated water could have on the concrete, and within a few moments, I found myself on the Wikipedia page about FritoLay.

Concrete Pavers
http://www.homedepot.com/p/12-in-x-12-in-Pewter-Concrete-Step-Stone-71200/100333077
Spray Bottles
http://www.homedepot.com/p/Continental-24-oz-Sprayer-and-Bottle-3-per-Pack-CMC9223SP/205907081

1. Sakrete Concrete and Mortar Dissolver
Meant to remove concrete from surfaces, looking to apply it for creating porosity
2. Sulfuric Acid
Generally strong acid that should dissolve some of the concrete
3. Carbonated Water
The carbon dioxide may cause carbonatation
4. Calcium Chloride
Removes calcium hydroxide, an important component of concrete
5. Gypsum dissolved in water
Causes cracking and loss of "stickiness" in the concrete

What is 20% Time? What is pervious concrete? Why do you want to create it?

Twenty Time is a project idea that has been used by huge companies like Google as well as schools like Saratoga High. The basic idea is that students (or employees) are given 20% of their time in school (or at work) to do something they are passionate about. In our Biology class, everyone is doing a 20% Time project related to the sciences because the project needs to be relevant to what we are learning in some way.

In California, we have a huge drought problem. Even when it rains extremely hard, the water just floods and flows into the ocean rather than entering underground water deposits, known as "aquifers". The main reason for this runoff is that concrete covers virtually every square inch of ground in Saratoga. Pervious concrete, which was originally used due to it's lower cost, allows water to pass through it. Water is able to pass from the surface of the concrete to the soil beneath due to the absence of fine aggregates (small particles) in the concrete. The only problem is that most surfaces are paved with regular concrete rather than porous. And removing this regular concrete to put down porous concrete is a big hassle.

To get past this problem of having to remove and repave, my 20% Time Project asks the question "Can you convert regular concrete into pervious concrete by using chemicals? Can it be done while retaining the concrete's compressive strength? Can it be done using environmentally friendly chemicals?".

To answer this question, I will purchase regular concrete slabs and test their porosity. I will first place each concrete slab in a tub to spray it with a chemical and let it sit for 24 hours. I will then place the slab above a bucket and spray water onto the concrete slab. The amount of water that passes through and enters the bucket in 30 minutes after pouring will be measured. I will rate the concrete's porosity on a scale from 0 to 100 based on what percentage of water that I poured passed through the slab. My control will be conducting the porosity test on an untreated slab of concrete. I will execute the test on multiple concrete slabs that are each treated with a single chemical. I doubt I will find a "perfect" chemical by the end of this project that causes complete permeability, does not remove structural strength, and is environmentally safe.

By Saturday, March 19th, I aim to have completed my research on what 14 chemicals I will test. By the Saturday after that (3/26), I aim to have 15 18" x 18" concrete slabs as well as the chemicals that I will either find at home, order online, or get from a local science store. Each Friday evening starting April 1st, I will spray 3 chemicals onto 3 concrete slabs and let it sit for 24 hours. Then on Saturday evening, I will pour water on all three at the same time and watch them for 30 minutes while taking notes. At the end, I will measure any water that has entered the bucket. The following Monday I will write a blog post in class summarizing my observations. Because I will be out of town for 1 week in April, I should be done testing all 15 concrete slabs on May 6th.

If any of these tests give considerable results (porosity of more than 30 on my scale), I will check whether the chemical is environmentally friendly. If it isn't, I will find similar chemicals that are. This will all be done while another batch of 15 slabs is on the way. After determining 6 eco-friendly chemicals to test, I will spray all 6 slabs on Friday (maybe 5/27) and test them the next day. If any of these have the same effect as the prior ones that worked, I will name it the winner and consider my 20 Time project very, very, very successful.

However, I doubt I will ever get to this point and find an environmentally friendly chemical that converts regular concrete into porous concrete. But if I do, I may continue into summer break and find a chemical that not only increases porosity and is eco-friendly, but also preserves the structural integrity of the concrete.