Time Of Use Puts Your Business: Fill & Download for Free

Oh, man. I’m a bit of a walking assortment of fetishes. It might be faster to list the things that aren’t my fetish, in fact.I will almost certainly forget some, but I’ll take a stab at answering this question:Group sex: This was the first fetish I discovered—literally the first day I had sex. I lost my virginity in a threesome. A few months later, I started dating my (now ex) wife, and 24 hours after we started dating, almost to the minute, another woman asked me out. She ended up dating my best friend, who had nearly started dating my ex-wife, and we formed what would today be called a “polyamorous quad,” though we didn’t have that language back then. Threesomes and foursomes became a regular part of my sex life…and still are today.Bondage: I’ve always been interested in bondage, for as long as I’ve been interested in sex. My second celebrity crush as a kid was Louise Jameson, who played a character called “Leela” in the Tom Baker episodes of Dr. Who. She was often getting tied up or strapped down, which totally carbonated my hormones.On my first date with my ex-wife, I had some rope in the back seat of my car (for reasons unrelated to bondage). When she saw it there, she asked me to tie her up. That date was interrupted when a scrawny, half-starved kitten jumped through the car window, but bondage remained a regular part of our sex lives from then on, and is still part of my sex life today.Fisting: I honestly don’t remember how or where I first heard of fisting. I remember very clearly the first time I did it, with my ex-wife. She had a single continuous orgasm that lasted for nearly half an hour. I thought I’d never get my hand back! I have fisted almost all my lovers (I’ve had two first dates that ended up with fisting, in fact), and it rarely fails to produce epic orgasms. I’ve had lovers go completely nonverbal from it.Flogging/impact play: For a long time, back when I was young and naive, I always thought “well, yeah, I’m kinky and all, but this whipping stuff is just way too much. I’d never be into that.That changed when one of my girlfriends took me to my first BDSM convention in Atlanta. She was a straight-ahead sexual sadist, and she loved pushing my boundaries. During open play in the dungeon one night, she volunteered me as a flogging bottom, and I discovered it was nothing like what I imagined.That story is the basis for a Mystery Box Theater presentation I’m planning to do in Portland in the not too distant future, Mystery Box Theater being a regular monthly event where people get up on stage in front of a large audience to tell stories from their sexual past.Domination and submission: This came about as a result of experimenting with bondage. I discovered that, much as I like tying people up and being tied up, I like telling people what to do and being told what to do even more. My ex-wife and I explored D/s in a number of ways from both directions. Great fun!Orgasm denial: My ex-wife really loved doing this to me. So does my crush. It’s interesting, because extended periods of teasing and denial (by which I mean for days or weeks, or even months, at a time) create a kind of background fog of sexual arousal that adds color and flavor to everything I do.I had a FWB relationship for about six years, and she really enjoyed orgasm denial. One night, we decided to see how long I could keep her right on the edge of orgasm without letting her get off. The answer turned out to be “six hours and forty-seven minutes.” I sent her home in that state without an orgasm.Forced orgasms: I’m capable of multiple orgasms. I have been for most of my life. One day, while my ex-wife and I were housesitting for her parents while they were on vacation, she tied me down to the floor, got on top of me, and decided to see how many times she could get me off.The answer turned out to be 22 times, which was a personal record that lasted almost 30 years. The first few were awesome. After that, I was afraid I was going to die. By the time we hit 15 or 16, I was afraid I wasn’t going to die. There’s a reason forced orgasms are a popular torture/punishment in BDSM!My partner Maxine is really into forced orgasms…in fact, the last time I saw her, she held me down and forced me to get off over and over until I passed out. That was interesting. My crush is a huge fan also.Humiliation play: Another one my ex-wife introduced me to, at first through dirty talk (which is really almost a fetish of mine in its own right) and later through physical degradation. Fantastic, fantastic fun.Needle play: I’m not sure if it really counts as a fetish, but I do enjoy putting needles in people. This was my first date with my partner Maxine, who is very much into it.Erotic wrestling: My partner Zaiah and I met online. When we met in person for the first time, we negotiated an arrangement where when we met, we would wrestle…winner gets possession of the loser’s body for the night.She won. Barely, but she won.Pegging: My ex-wife really really wanted to do this to me. A strapon was one of the first of many sex toys we owned. I was a bit hesitant at first—it didn’t sound terribly pleasurable to me, but hey, she wanted to do it, and I’m usually game for trying things my lovers want.Turns out prostate stimulation is absolutely the shizzle. It’s been one of my favorite sexual activities ever since. Damn, I love me some pegging.Teledildonics: I was one of the first people in the world doing this. I invented a prototype Internet controlled sex toy back in 1998. Wrote the software for it and everything. Tried to market it. Sold a handful of units under the name “Symphony.” Lost a ton of money—I didn’t have the capital to have them manufactured, so I was making every one by hand (I sat there soldering circuit boards on the kitchen table). Lost money on every sale, which, as it turns out, is not the way to make money.Since then, I’ve built a wide range of high-tech prototypes as a hobby: a prototype vibrator connected to an EEG that you can learn to control by thinking about it; a prototype proximity controlled wearable vibrator that starts running when anything gets within four feet of you and runs faster and faster as things get closer (the idea is you put on a blindfold and learn to navigate just by sexual stimulation), a prototype wearable vibrator connected to a random number generator so it runs in a constantly changing pattern that you can’t ignore but also won’t get you off; and a sensor-equipped strapon that uses direct neural stimulation so you can feel touch in the dildo (I’ve applied for a patent on that one).Electrical play: I own not one, not two, but three violet wands. They’re always a hit at sex parties. I was introduced to the violet wand at a play party in Tampa by a woman whose name I no longer remember.Erotic body art: My partner Zaiah turned me on to this. She loves drawing and painting on my naked body.Blading: Another fetish Zaiah introduced me to. This is the process of using a very sharp knife such as a scalpel to make shallow surface cuts in the skin in intricate and elaborate designs. There are photos of me somewhere with a design based on the Kanji character for “Toy” cut on my back.Resistance play/rape fantasy: I started doing this with my ex-wife. She liked role-playing scenarios where she would be “blackmailed” or “coerced” into having sex. Later, my current wife and another partner of mine really liked more physical, jump-out-and-grab-me, throw-me-against-the-wall styles of rape play. I’ve had a partner who really, really got off on acting out abduction scenarios.Consensual non-consent: This takes a lot of forms other than rape fantasy. Zaiah and I have a long list of negotiated agreements in which we explicitly waive the right to say “no.” When we go on long trips, whoever’s driving can do whatever they like to the passenger’s body at rest stops, and the passenger can’t say no. Coming to bed naked is consent to be molested in one’s sleep.I’ve had a partner who really liked taking sleeping pills and then having me have sex with her. (She wouldn’t remember what happened the next morning except in jumbled fragments, so I would write on her body a record of the things I did to her, which she would find the next morning.)Designing sex toys generally: This is an offshoot if the teledildonics stuff. In the process of making prototypes for the sensor-equipped strapon, I have had to teach myself 3D modeling, 3D printing, moldmaking, and silicone casting. Right now, as I type this, I have two 3D printers downstairs that are busy making molds for sex toys (a single mold can take over a day to print, because 3D printers are appallingly primitive, low-tech devices about in the same state of development as the He earliest dot matrix impact printers).Phone sex: Back in the days when I used to run an old-school dial-up computer BBS, I hosted parties where users could get together in real life and meet each other. One of my users was an absolutely stunning, scorching-hot woman named Tracey, who used the BBS handle Black Magic. We became good friends.I was talking to her on the phone one night when she mentioned she liked phone sex. I was all like “I don’t get phone sex. It seems like it would be boring to me. I enjoy seeing and touching my lovers. That’s the whole point of sex! You can’t do that over the phone. Phone sex sounds boring.” She said “I bet I can get you to change your mind.” She was right.Sexting/Cybering: In the early days of America Online, I had a profile that linked to my polyamory site. I got a random IM one day from a woman who said she and her husband were interested in exploring it, but didn’t know how to get started. We started chatting, and over the next few months we became online friends. She mentioned one day she really liked cybering. I’d never done it, so she was all like “Oh, we need to fix that, it’s fun!”She was right. She was and still is one of the more creative people I’ve ever encountered. We were cyber and text lovers for more than five years. We talked on the phone as well, though we never met in person.Blindfolds: My ex-wife and I played with these a bit, but never really got into them. It wasn’t until I had another lover who was really really into being blindfolded that I totally got the appeal. There’s something incredibly intense about not being able to see or anticipate what will happen next that’s just absolutely intoxicating. It’s not the blindfold, it’s what it means at the hands of a skilled, creative lover.Sensation play: During my FWB relationship, my FWB was a big-time sensation junkie. We would use all kinds of things for sensation: rabbit’s fur, ice, the end of a toothpick, you name it. She would lie still for hours while I worked my way over every square inch of her body creating all kinds of sensations.Mummification: The same partner who introduced me to the joys of blindfolds also introduced me to mummification. She really liked tight bondage. I would get rolls of pallet wrap (think heavy duty Saran Wrap) and wrap her tightly from shoulders to feet so she couldn’t even wiggle, often while she was wearing a vibrator or other sex toy. Then I’d cut holes in the wrap to play with her nipples and clit.My partner Zaiah enjoys mummification too, though she uses vet wrap rather than pallet wrap. She’s done this to me many times. It’s fun to be completely wrapped up and totally immobilized, with just my head and penis exposed.Sounding: My partner Maxine introduced me to sounding during an orgy for her birthday a few years back. She and my crush both really, really like sounding me. I wouldn’t go so far as to say I enjoy it, exactly, but it certainly is intense, I’ll give it that. I now own not one but two sounds as part of my sex toy collection.Dollification: Also something my partner Zaiah introduces me to. She really likes being used as a sex doll. We have a doll mask I can put on her, with the rule being while she’s wearing it she is absolutely forbidden to move or speak. I can just place her in whatever position I like and use her as a masturbatory toy. It’s really really hot.Fucking machines: When I lived in Tampa, I attended a monthly play party whose hosts owned a Sybian, a very high end fucking machine that a guy I know once described as “the machine that rips orgasms out of women.” I’ve never known anyone to use one and not have massive, screaming, earth-shattering orgasms.Later, I had a lover for a time who was dating the guy who invented the Monkey Rocker fucking machine. He gave me a two-person Monkey Rocker as a gift (which raised some eyebrows going through airport security at LAX!), that I still have today. It’s quite popular when I host sex parties.Grope boxes: I was introduced to these at a play party and instantly thought it was one of the hottest things ever. It’s a large upright wooden box, big enough to stand a person in. You tie someone to the inside of the box and close the door. The box has holes in the sides and front that people can reach through to grope and fondle whoever is inside. The person inside can’t see who’s fondling them and can’t do anything to prevent it.I’ve always wanted to build a grope box. The only reason I haven’t is we don’t have enough space for it.Objectification: This is yer another fetish I first started exploring with my ex-wife. She really enjoyed being objectified during sex—a lot of our dirty talk revolves around me telling her how I was just using her for my own pleasure, which really got her hot. This is one of Zaiah’s favorite fetishes as well.Erotic hypnosis: After I burned my foot earlier this year and then discovered I can no longer tolerate opioid pain medications because they make me throw up, I started using cannabis for pain management. I learned that in addition to being extremely effective at pain management, cannabis places me in a hyper-suggestible state…something my crush absolutely loves. We’ve both been wanting to explore erotic hypnosis, but haven’t been able to do so yet.Medical play: I don’t actually remember how I got into this particular fetish. It’s always held a certain appeal: the patient on the exam table with her feet up in the air, while the doctor of questionable integrity probes and examines her… I’ve explored this with some of my partners (did you know you can get speculum ridiculously cheap on Amazon?), but it’s something I’d love to do more of. I have a friend with whom I frequently flirt. She owns a hulking, heavy, mid-1940s antique gyno exam table. I’ve often entertained thoughts involving that table.

You don't need to make an appointment for an oil change at Walmart, no matter who comes first. Some customers mentioned that Wal-Mart’s timing of oil changes has never been a problem. They even rode in multiple cars at the same time and changed their oil in a relatively short period of time.All appointments are welcome, and your waiting time will vary according to how busy the automated center is.When will Wal-Mart Motor Oil open? When will the Wal-Mart Auto Center open?The Walmart Care Center usually opens at 7 a.m.When will Wal-Mart Motor Oil shut down? When will the Wal-Mart Auto Center close?The Wal-Mart Car Center usually closes at 7 or 8 pm. Call your local Wal-Mart Automotive Center to confirm.Some comments of people about the Walmart Supercenter oil change service——do they need an appointment?“As long as they show up on most Saturdays, they will drive the car right away. After 20 minutes, I received the car and they gave me the car keys. In addition, you will never have the trouble of a big store trying to sell you electric shock... exhaust system... or needing a new gearbox BS again! They even checked the work carefully and marked the filter and drain plug to indicate that they had been checked before completion.”“My wife and I are in self-isolation due to Covid-19 and she suffers from congestive heart failure. We are all worried that she will be sick or that I will bring the disease home. The oil in her car is running out, we know we need to get a new one. I called the local Wal-Mart in Dodge, Kansas, and talked to a lady named "Rory". She is so understanding and sympathetic to our situation. She said I can park the car in the parking lot and stay in the car. She helped me put the new battery in the trunk and said that I didn’t even need to sign the application form. She is very good, very respectful, and does not make me feel paranoid or hygienic. Wal-Mart generally does not take out the battery and the like. It usually requires personal transactions and signatures, but at this terrible moment, they put these regulations aside.”“I have to change the oil. An employee greeted me. Then he told me the price of the oil change, and I let them do it. The waiting time is a bit longer than expected.”“ This was in Portland Texas. It varies greatly depending on location! Many things are better with service workers in Portland TX. Most of the service workers are polite & engaged in whatever the task is they are working on.”“Very clean and organized service. Fast, courteous, friendly, and affordable. Called and they scheduled an appointment for my truck to be serviced and gave me the exact details and the process to take place.”Therefore, all appointments are welcome, and your waiting time will vary according to how busy the automated center is.It is important to note that if you are going to perform certain maintenance or the type of filter your vehicle uses is not common, it may take longer to change the oil at Walmart.Many experts suggest that you either always perform oil changes at Wal-Mart or not. This is because Wal-Mart’s technicians may tighten the bolts too much so that others may find it difficult to loosen the bolts. On the other hand, if you prove to them that you only change oil at Wal-Mart, Wal-Mart is willing to change the oil pan of your vehicle.Walmart is rated as the cheapest company to provide high-quality motor oil, but the exact cost depends on the make and model of the vehicle and the year and type of oil. Generally, a traditional engine oil replacement costs about US$20, while a synthetic engine oil replacement costs up to US$75.Although changing the oil can save you a lot of money, you still need to consider your own risk and change it yourself, especially if this is the first time. Oil changes do not require a lot of money, so unless you have the required mechanical skills, it is recommended that you risk saving a few dollars.Walmart oil change costsWal-Mart’s oil replacement cost depends on the brand, model, and year of your vehicle and the type of oil you choose. Generally, the cost of an oil change is less than $20; however, if you use certain oil types, this number can be as high as $100.In an in-depth survey of the cheapest and best oil change services, Wal-Mart topped the list. For example, if you pay about $20, you can get the following services:Fill up to 5 quarts of Quaker State Advanced Durability regular motor oilInstall case lubricantInstall the oil filterCheck your battery performanceAdjust tire pressureOn the other hand, if you pay an extra $10, you can get the so-called "Wal-Mart Standard Oil Change Kit", which includes regular engine oil plus some vacuuming and additional oil level checks.Now, if you decide to use a different type of oil, the price may be slightly higher, but still lower than the retail price of other companies. For example, Wal-Mart’s synthetic oil replacement cost is about $50, while the cost of synthetic blends is about $40.Wal-Mart’s synthetic oil replacement is considered the cheapest on the market because it is about 41% lower than any other company’s price of at least $85.How much is Wal-Mart’s cheapest oil change?Wal-Mart provides the cheapest oil change service on the market, and if you want to use regular oil, the lowest price you can get is about $19.88. However, if you decide to upgrade and use synthetic oil, then the cheapest oil change price at Walmart is about $40.Does Walmart have oil change coupons?There are many websites where you can find good deals on Wal-Mart’s oil change. Even if you don't get the discount for the oil discount, you can get the discount when you buy the oil itself, and then bring it to the mechanic as needed.Will Wal-Mart change the oil?Some people worry that Wal-Mart’s oil is not good because they will reduce the quality of the oil. However, this is incorrect because the oil cannot be diluted. If there is water in the oil, you will see the oil floating on top of the water.Another thing is that several people mentioned that Wal-Mart’s SuperTech company’s house is connected to Shell. Shell’s products are very good.However, some customers complained about staffing, not the oil itself. Although you can hire a very professional Wal-Mart worker to change the oil for you, you may encounter a situation where people without the required experience change the oil.What kind of oil motor does Wal-Mart provide?Wal-Mart Engine Oil Change offers four different types of engine oil, including:Fully Synthetic Motor OilThink of synthetic motor oil as the best motor oil that provides maximum motor lubrication. Very useful for vehicles that require a high level of performance and lubrication.In order to obtain this lubrication quality, synthetic oil is sometimes two to four times more expensive than any ordinary engine oil. Therefore, customers who prefer cheap oil changes may not regard synthetic oil as the best choice for their vehicles.Synthetic hybrid motor oilThis oil is between ordinary oil and synthetic oil. It provides lubrication similar to synthetic oil to a certain extent and is considered to be cheaper than synthetic oil. The mixing option uses some additive fluids to improve the quality of this oil and increase the lubricating ability.Conventional oilConventional oil is the conventional and most common type of oil you will hear and encounter. Although widely used, conventional motor oils cannot provide the highest lubrication quality. Therefore, it is most suitable for light vehicles that do not require high lubricity.High mileage motor oilThis is a special type of motor oil used in vehicles with high mileage (above 75,000). High mileage oil has some characteristics that can help these old cars last longer by reducing oil consumption and oil leakage.There are common questions about oil change:Should I change the oil?An oil change may sound like a saving. However, for many reasons, you need to take a step back and think again. First, you need to consider the convenience and other risks.Although changing oil is a simple task, there are many other steps you need to take, and this requires a lot of time and effort. For example, if this is your first oil change, you need to spend time learning how to change the oil, the materials to be used, and the mistakes to avoid when changing the oil. In addition, dirty oil must be discharged into a specific container in some way. Is it all worth it?In addition, it is well known that any first attempt at DIY can go wrong. Therefore, you may risk saving only a few dozen dollars. Professional technicians are ready and well-trained to ensure that they carry out oil changes correctly.Can I refuel without changing the oil?Every car must have a certain level of oil to lubricate and prevent the engine from overheating. This oil must be very transparent and have a honey-like color. Over time, the oil may absorb some dirt and become contaminated. If the oil is too dirty, your engine may have many problems, which may eventually lead to a complete engine failure.Now, adding oil instead of changing oil does not solve the problem. This is because when you add engine oil, the dirt is not washed away from the engine oil, so it can properly lubricate and maintain the engine.Therefore, you may need to spend some time in the garage or Wal-Mart to change the oil, but in a short period of time, you can save a lot of energy and money to deal with more complex problems.How often should I change the oil?As mentioned earlier, using clean engine oil can save your vehicle and reduce the hassle of dealing with complex problems. Therefore, it is important to maintain and fully understand how often the oil should be changed.Generally, the frequency of oil changes depends on the make, model, and year of the vehicle, as well as the driving style and conditions. The best starting point is your vehicle manual. Although the manual has good expectations about when to change the vehicle oil, in some cases you may need to change the vehicle oil more frequently.As experts recommend, you need to change the oil every 3,000 miles. If you own a newer vehicle and use high-quality oil, you may have to wait for 5,000 to 7,500 miles.How much oil do I need to change?Every car has a certain oil capacity. You don't want to add too much oil and let this oil enter the engine and cause damage to it. In addition, you do not want to add a little oil to the engine oil, which will cause complicated engine problems.The best starting point is the user manual of the vehicle. It should have exact information about how much oil you need to add, and some suggestions for specific types of oil. The capacity depends on the make, model, and year of the vehicle.In general, how much should I pay to change the oil?According to the Kelly Blue Book, the cost of oil replacement depends on the manufacturer, model, and year of the vehicle, and the type of oil you want to use. Generally speaking, the price of conventional motor oil is between US$35 and US$75, while the price of synthetic motor oil is between US$65 and US$125.Is it cheaper to bring your own oil to change the oil?If you want to change the car oil yourself, many people will buy it. Interestingly, others bring their oil to the garage or dealership to save some money. Well, dealerships and garages allow you to carry oil. In this way, you can save the total bill to be paid.Therefore, yes, it is cheaper to carry your engine oil for an oil change.Is synthetic oil worth it?According to AAA, synthetic engine oil is considered "significantly better" than regular engine oil because it improves engine oil test scores by approximately 47%.Compared with traditional engine oil, synthetic engine oil has several advantages, including:It provides fewer emissions and is therefore environmentally friendly in this respect.It helps reduce the fuel consumption of the engine. As a result, the vehicle will have a better fuel economy.Compared to standard options, it reduces engine wear by providing significantly better lubrication.You don't need to change the vehicle's oil frequently, because it takes longer intervals to change synthetic oil.This oil is of high quality and is considered more effectiveWhen you seek "all-weather protection", synthetic oil is better.Synthetic oils can provide additional help to eliminate engine dirt or sludge deposits.

From what I can see, the lunar soil and lunar dust contain at least the elements, if not the molecules, needed to make Portland cement; though, some processing of it would be necessary to make Portland cement, which is the most common type of cement used in ready-mixed concrete today. It certainly is not the only type of cement possible; Roman cement is another historical example. Both Portland and Roman cements are hydraulic cements.Ultimately, whether lunar dust will be used for making, on the moon, the cement needed for making lunar concrete will depend on the economics of the situation (e.g., “How much of paradise are we paving?” / “Is it more expensive to build a cement plant on the moon with components transported by rocket from Earth to the Moon, or based on our level of demand, is it more cost efficient to transport the cement, ready-to-use?”). Intuitively, I think excavating the lunar surface for coarse and fine aggregates, since these are, by far, the most abundant constituents of concrete, will pass the economics test over lifting them into low Earth orbit and then transporting them one light-second to their destination stockpiles.I would like to explain this answer so as to incorporate the notion of whether concrete can be made on the moon from materials found on the moon and, also, while considering whether this would be cheaper than shipping the necessary materials from Earth to the Moon.We need some basic data about ready-mixed concrete mix design to do this. Thankfully, I ran a concrete plant for over half a decade.3000psi concrete is a standard strength building material here on Earth, though we can achieve twice that strength or more with a bit of luck, with maintaining appropriate (i.e., low) levels of the water-cement ratio, and with careful placement.You have a general range of 300 lbs to 650 lbs of cementitious materials needed per cubic yard of concrete made from silaceous coarse and fine aggregates in order to achieve compressive strengths of at least 3000psi at 28 days.Already, we have some jargon terms.Cementitious materials: In general, we’re talking about Portland cement and fly ash. Fly ash is made from burning coal; it’s a pozzolan. I’m unsure if this has any economic value on the Moon, if it could even be made there, so I’m just going to recognize that such things exist and then, immediately, forget that they exist, so as to condense away some of the jargon. Our lunar concrete will be made with Portland cement as the only cementitious material.Coarse aggregates: These are rocks. I could go more into it, but there’s really no purpose in it. Crushed river gravel and crushed limestone are common coarse aggregates used here on Earth. The size of the rock you need depends on the thickness of the slab you’re casting. If my memory serves, the largest coarse aggregate should be about 1/4 the thickness of your slab; e.g., if you’re casting a 4″ slab, then your coarse aggregate should be no more than 1″.Fine aggregate: This is (again, in general) concrete sand. Sand you excavate from river bottoms and pass through various sieves to achieve a distribution of particle sizes appropriate for the use in ready-mixed concrete.Compressive strength is measured by casting cylinders filled with your concrete. Usually, you don’t add any steel reinforcement in them, such as rebar, wire re-mesh, or nylon or steel fibers. After a specified amount of curing time (e.g., 7 days, 14 days, 28 days, 56 days, etc.), the concrete core you cast will be subjected to a concrete cylinder compression test (i.e., break test). Force is applied to the concrete cylinder until it fails (e.g., it breaks apart in some fashion). Whatever amount of force it took, per square inch [PSI], to cause the concrete cylinder to fail is the concrete’s compressive strength.Ex. You are building a home, and your architect tells you that you need 3500psi concrete for your foundation. Unless otherwise stated the architect is telling you that the concrete you order and place should reach at least a compressive strength of 3500psi at 28 days.Modern concrete uses chemical admixtures to alter the end results of your concrete; for the sake of brevity, I will just admit those from this analysis, for I have no idea how these chemicals will work on the lunar surface, or if they would even be appropriate.After that, all you need is water! Once you add water to cement, you start a process, an exothermic reaction, that is an irreversible chain of hydration events.We should go over some arithmetic first before we move on to mix design.In the United States, it’s common to sell concrete by the cubic yard (CY), though I’m sure it’s more common to sell by the cubic meter in other places. Since I know the CY conversions by heart, I’m going to go with that.One thing you need to know is “How much concrete do I need (e.g., to cover a certain area with a slab of concrete of a certain thickness?” — For simplicity, we’re going to stick to square and rectangular slabs.The general formula is# CY Needed = [(length in feet) * (width in feet) * (thickness in feet)] / 27.Ex. I have an area that is 100′ x 200′ that I want to be 6″ thick.[math]\frac{100*200*\frac{6}{12} }{27} = \frac{10,000}{27} \simeq 370.37 CY[/math].This represents the minimum amount of concrete that you would need to cover a 20,000 square foot (SF) area with a slab half a foot thick.We can imagine that this might be the foundation for a permanent structure we would like to build on the moon. In order to determine the economics of this build (e.g., “Should we use materials on the Moon that we have to process, or should we transport materials that can be used as-is from Earth to the Moon?”), we need to know how much a CY of concrete weighs.Unless we can find water on the Moon, water will have to be transported from Earth anyway, so we can omit water weight from our calculation. I will assume the transport cost of water is a sunk cost, because I have no reason yet to think, even if water were to be found on the Moon, that it would be of appropriate quality for use in the manufacture of ready-mixed concrete; and, even if it were of suitable quality, I don’t know that it would be cheaper to excavate, drill for, or otherwise harness the lunar water, compared to transporting water from Earth, or even whether lunar water reserves would be allowed for industrial uses (e.g., rather than exclusively for human consumption).What we need is the expected weight of an amount of our dry mix concrete, which, when the appropriate amount of water is added to it later, will yield 1 CY of concrete.I have no understanding of the characteristics of lunar aggregates, so I must use a mix design that assumes the use of those of terrestrial origin. Once we have that, we can make some qualifications to it to apply the concept to lunar-origin possibilities.I assume we want a strong concrete and that such long-term high compressive strength will come, on the Moon, in part due to higher levels of cementitious materials — particularly, Portland cement, in this limit — just as would be true on Earth.Portland Cement = 650 lbs per CY.When the coarse aggregate (CA) size is, on average, 1″, thinking of needing 51% to 55% of coarse aggregates, in proportion to the total amount of non-cementitious aggregates and with the resulting amount of fine aggregate (FA) deriving therefrom, is a fine place to start for our mix design.CA(1″) = 1725 lbs per CY = [math]\frac{1725}{3271}[/math] = 52.7%FA = 1546 lbs per CY = [math]\frac{1546}{3271}[/math] = 47.3%We are now able to determine the 1 CY dry mix weight: 650 + 1725 + 1546 = 650 + 3271 = 3,921 lbs.While I have experience creating mix designs, we would need to add water to this mix, on the Moon, and cast break test cylinders on the Moon, and break the cylinders, on the Moon, in order to verify that this design, indeed, achieves or surpasses the minimum compressive strength required for our project.We use our experience to create a prototype concrete mix design, and then we test it, empirically, to verify our assumptions.It could be that the mix design fails to achieve the strength required in the time allotted. This could result for a variety of reasons; we’d need to figure out what was going on, and fix it.If the break test cylinders consistently broke at higher-than-required compressive strengths after being allowed to cure for the allotted period of time, then we should be able to reduce the amount of Portland cement in the design. Anything we can do to save on the materials needed per CY (i.e., their weights per CY produced) will reduce our transport costs attributable.Even more importantly, if the coarse and fine aggregates found on the moon were substandard compared to their terrestrial “equivalents,” we might be able to substitute the lunar aggregates for the terrestrial ones and still achieve the required compressive strengths in a timely fashion. Rather than reducing our Earth-to-Moon transport costs, we’d be eliminating them.Another important empirical test is that of volume produced versus volume expected to be produced.If you haven’t already figured it out, the reason why, in the arithmetic equation above, the divisor is 27 is that one CY has 27 cubic feet in it.This is a yield calculation, and you can imagine a few ways of doing it, some of which are smarter than others.Let’s say that I batch up 1 CY of concrete per my wet mix design; you need to add your water to do this, and we can calculate, at this point, the expected value of the weight of 1 CY of fresh (wet) concrete. For the aficionados among you all, the jargon term for fresh concrete is plastic concrete. That doesn’t mean it has plastic in it! Plasticity is the characteristic of concrete to the extent that the dry mix and the water recently have been mixed together. Plastic is sort of like flowable, but there is nuance in the meanings of the two words.So far, I’ve just been assuming that 1 lb of 1″ rock on Earth has the same volume as 1 lb of 1″ rock on the Moon, not taking into account the difference in gravitational acceleration between the two objects, with respect to the rock, and other relevant ambient factors. We’re going to continue that limiting argument for brevity’s sake.I will impose on the mix design that it has 28 gallons of water needed per CY of plastic concrete ready-mixed.So many factors affect the weight of a gallon of water here on Earth; we just have to pick something for our purposes at the moment. 8 lbs per gallon was an Earthly approximation that I, in the business, used with good luck for years.Ergo, if the dry mix per CY weighs 3921 lbs, and the water needed to hydrate 1 CY of dry mix weighs (28 * 8 lbs =) 224 lbs, the total weight of 1 CY of plastic ready-mixed concrete is 4,145 lbs.Yield Test Ex. — Impractical:I construct a very sturdy box that has an interior volume of 1 CY.I batch 1 CY of wet mix, using the highly calibrated weigh scales of a ready-mix concrete plant, and dump it into the box.If it overflows the box, then our mix design is yielding too much.If the box is not completely full, then our mix design is yielding too little.If it exactly fills the box, then our wet mix design, for 1 CY of plastic concrete, yields 1 CY of plastic concrete. We can trust our arithmetic formula to tell us how many CY of concrete we need to cover a specific area.Yield Test Ex. — More common:I construct a very sturdy 1 cubic-foot box and weigh it.I batch 1 CY of wet mix and discharge some into a wheelbarrow.Immediately, I use a scoop to transfer enough plastic concrete so as to fill the box, and I weigh the box when it is exactly full. I record how much it (concrete + box) weighs and subtract out what the box’s empty weight was. This gives me a #.(# lbs * 27) should equal 4,145 lbs.In practice, likely it won’t do that exactly. These are sampling techniques, of course, so we’re in the statistical realm, and the more trials like this that you do, the closer the average should be to 4,145 lbs.Unless your yield is off!Repeat this test five times and average your results, and compare what the average yield is, in pounds, compared to your expected yield in pounds.You can determine if you’re overproducing, underproducing, or yielding as expected, using this method. It doesn’t require you to have a forklift that can lift a very sturdy box onto a very sturdy and accurate weigh scale.Not all ready-mix plants will have ground weigh scales; usually, these are associated with aerial weigh hoppers.Whether using the practical or impractical method of yield testing, if you find variances, then likely you need to alter your mix designs even if the break test results give you the end compressive strengths you require.If you’re going to be as economical as possible, then you need to be able to figure out how much concrete to batch for a specific job without having too little or too much produced. Both of those scenarios are examples of wastefulness.On the moon — you can’t afford to waste materials that you have transported the 1 light-second, or more, that separates the Earth from the Moon.In the literature you can find that it costs about $10,000 per pound to lift something into low-Earth orbit.In 1999, NASA famously estimated the cost of putting "a pound of payload in Earth orbit" at about $10,000.Moon Express itself says its first unmanned mission to the Moon, carrying just 500 pounds of payload, will cost about $10 million.We can do the circumlunar calculation using the latter: $10,000,000 / 500 lbs = $20,000 per lb.If the materials for 1 CY of wet mix concrete all come from Earth, then per CY, you have a transport cost of, hopefully at maximum, $20,000/lb * 4145 lbs/CY, given that water is carried from Earth to the Moon, and disregarding any fixed assets needed to be established on the Moon in order to make this happen.We get a transport-only cost of $82.9 million per CY.The Space Launch System (SLS) of NASA has heavy lifter variants of its rockets that will allow 57,000 lbs of trans-lunar-injection (TLI) payload, to 82,000 lbs of TLI payload, to 99,000 lbs of payload to be delivered to an orbit even past one that would include the Moon and bring it back toward Earth.An unofficial 2011 NASA document estimated the cost of the program through 2025 to total at least $41bn for four 95 t launches (1 uncrewed, 3 crewed), with the 130 t version ready no earlier than 2030.If we just take this number, ($41 billion / 4 launches) = $10.25 billion per launch, then we can estimate the cost per TLI payload, with a liberal or minimal (who knows?) payload of 99,000 lbs, to be[math]\frac{[\frac{41,000,000,000}{4}]}{99,000} \simeq $103,535[/math] per lb.From these analyses, we appear to have a five-fold difference in the cost-per-pound to deploy resources to the moon. If I were to guess, that would be because the NASA documents take into account sunk initial and continuing capital expenditures, and the others, like Moon Express, are thinking and reporting in terms of delivery on systems whose costs are already paid for in the model and not properly (i.e., conservatively) allocated to the delivery vehicles and their contents.Using this data the per-CY cost of Earth-to-Moon transport of concrete materials would be $103,535/lb * 4145 lbs/CY.This suggests a cost to transport the materials from Earth to the Moon at $429,152,575 per CY.If we go back to our 6″ thick 20,000 SF slab, where we already figured we’d need about 370.37 CY of concrete to cast this slab, we can now say we need370.37 CY * 4145 lbs/CY = 1,535,184 lbs of material;the cost of transport to the Moon is $20,000/lb to $103,535/lb.The total cost for this 20,000 SF slab would be between $30,703,680,000 and $158,945,239,203.It’s worth noting, that with only one rocket, with a payload capacity of 99,000 lbs, it would take (1,535,184 / 99,000 =) just over 15.5 trips to carry the payload requested, even if you were NASA.We can check this, using a different set of data, such that each TLI mission costs $10.25 billion; rounding up, it will take 16 trips. Ergo, the expected cost is ($10.25bn * 16 =) $164 billion. Due to rounding the calculation checks out.For that amount of money, we’d only have a 20,000 SF slab. We’d have nothing to put on it; we’d have no lunar infrastructure with which to do anything more. So, we need to think about how much it would cost, inclusive of equipment and transportation costs, to create the capacity to produce ready-mixed concrete on the moon.For sure, I know that the moon does not have a dump truck or concrete mixer truck on it; we’d need at least one of those. The liberal estimate of for an empty weight of a proper, revolving-drum concrete mixer truck is 30,000 lbs. I wouldn’t expect an internal combustion engine to work in the vacuum of the moon, so we’d end up with an electrically powered (e.g., cord or battery) truck. The weight of the cab of these trucks is negligible compared to that of the frame, tires, drum, and mechanisms that allow the drum to revolve. As I have no idea what the difference in weight is between an internal combustion engine and batteries or whatnot, we’ll just assume the launch weight of one appropriate concrete truck is 30,000 lbs.A reasonable portable ready-mix concrete “plant” has an empty weight of 68,000 lbs. This includes the various cement and aggregate bins, conveyors, augers, weigh scales, admixture pumps, and control apparatus.One will need a loader with which to load materials into the bins. Komatsu is a great brand. Again, it runs off of internal combustion, so I assume something similar to it will be found. Considering the size of our production plant, a Komatsu loader that weighs around 41,500 lbs seems minimally appropriate.Let’s tabulate this just this far:30,000 + 68,000 + 41,500 = 139,500 lbs.These have an associated Earth-to-Moon transport cost of $2.79 billion to approximately $14.443 billion.Using another measure, we must think that our rocket has a max payload of 99,000 lbs, which — for the equipment — may or may not be able to be split up into smaller pieces, or constituent parts, for transport.Thus, it would take us 2 TLI missions to deposit this equipment on the lunar surface, and we’d have some extra capacity for transport of other things. Since these equipment structures and pieces of equipment must be maintained, I’d sink the cost and just say that another measure of how much this would cost would be 2 TLI missions, which would be $20.5 billion.So far, we have a loader on the moon; we have a small, portable concrete plant. This plant has bins for cement, coarse aggregate, and concrete sand. We have a concrete mixer truck into which to dump this material and mix it.To a realistic extent, our loader can scoop up lunar soil and dust and move it and raise it to a point that this material can be dropped into a set of sieves and conveyors to separate outthat which will become the fine aggregate;that which will become the coarse aggregate;that which will become the Portland cement.The FA will require a set of sieves and a mixing apparatus.The CA will require a set of sieves and a rock crusher.The lunar dust will have to be processed to some extent, which may involve chemical separation and process in a kiln.In the vacuum on the lunar surface, even with the other equipment we do not have yet on the surface — assuming we did have it —, you could move the fine and coarse aggregates from the processing location to the bins of the concrete plant.You could do that with the loader or the concrete mixer truck.How to move the cement created on the lunar surface from processing station to concrete plant is a more interesting thought. You wouldn’t be worrying about it aerosolizing as might happen on Earth; you’d be wondering how much of what you dumped into the loader would reach (and stay in) the bin.As fine of a powder as cement is, and with significantly lower gravity, this would be a task. You’d have to contain it in some manner, meaning even more equipment necessary.What can be said, at the moment, is that concrete probably can be made using the lunar soil and lunar dust. Not until you reach a critical production mass would it make sense to do this on the Moon, at least with respect to the Portland cement. It would be more economical to transport the cement from Earth and harvest the fine and coarse aggregates from the Moon.During the early-to-mid 20th century, men loaded materials from river basins, using loaders and excavators, onto dump trucks, from river basins; the proportions of river rock to sand excavated was not known with constant precision; and, buildings sitting on foundations constructed from concrete thereby mixed still stand today.There is an intuitive thought that, with an appropriate amount of cement, a variety of materials will “stick together.”That is what leads me to believe that lunar soil can be used for the coarse and fine aggregate portions of the mix design.Being able to process lunar dust into Portland cement is a capability of the future, when what we’re talking about already is something of the future.We will start by getting a truck, plant, and loader to the Moon. We will transport the quality cement from Earth and excavate the coarse and fine aggregates from the Moon, and that will be sufficient to build the foundations of many structures on the Moon.Once we have those, we can reconsider cement manufacturing on the lunar surface.