Advanced construction materials

Joseph Paul · 01-15-2010, 10:50 PM

Concrete is a wonderous thing. And it may be getting better.

Currently there are a couple of different products being used to retro fit existing buildings to make them less susceptible to bombs. Essentially it is a high rupture strength material bonded to the walls. When struck by an explosion the wall may break but it doesn't spew debris into the building. The bonding material helps take up some of the blast energy but more importantly it keeps the wall together to help prevent collapse and more wall coming down.

High strength concrete may be getting mixed with carbon fiber to improve its resistance to breakage and there may be more benefits in doing that at the nano level.

Anybody got any insights on ball parking such advances in regards to HP and DR?

Dwarf99 · 01-16-2010, 05:19 AM

You'll have to get more information before I can give you a decent answer but I'd say this new stuff is probably ruggedized, and it probably makes HT rolls against collapse. I could be off base...

I'm sure that if you can find some stats on the differences in pressure that each type takes to break that ratio would probably be good 'nuff. Also HP would probably be off the HP table in the back of campaigns.

Joseph Paul · 01-16-2010, 11:54 AM

And that HP and DR increase is what I am looking for.

From BigFuture.com - There are higher strength fiber reinforced concretes and geopolymers available. These run in to the 50,000 to 60,000 PSI range. Normal construction grade concrete is 3-5,000 PSI. The Massive Ordnance Penetrator (~30,000 lbs)is designed to penetrate 60 meters of 5,000 PSI concrete and can do 8 meters of 10,000 PSI concrete. That is quite a fall off in performance. If a doubling cuts penetration by a factor of ~7 then 20,000 PSI concrete would stop one with 1.1 meter of material.

Why use such strong (and therefore more expensive) materials? Well if you are in the future it may not be all that more expensive to build more resistant structures. In reality there is a brand of concrete with a 14,000 PSI rating getting a lot of use in NYC. Apparently people there want something a little stronger. Higher incidences of natural disasters may be a factor, or providing for currently unknown threats in a new environment, or by having it legislated as the government wants to make sure that buildings can be of use in event of invasion. Under UT firepower (ETC, ETK, APEP etc) buildings are of no use as cover against light ordnance.

So given that Basic pegs concrete at DR 12/inch and HP is the cube root of 8 times the mass what should better concrete have? Right now I get a DR 0f 90/inch for the 10,000psi material. I don't know how much denser it may be though for the HP.

For the MOP to work in GURPS it needs to deliver 28260 pts of damage to penetrate 60 M.

Dwarf99 · 01-17-2010, 11:21 PM

HP is based on the weight according to Object Hit Points Table and Size and DR of Structures both found on B 558

"typical weights per 1,000 square feet (sf) of area are 50 tons for wood frame or mud brick, 100 tons for steel frame or brick, and 150 tons for stone."

Joseph Paul · 01-18-2010, 08:50 PM

I get what RAW says about HP. I just don't know if the better quality concretes have a significantly different density. Also if the DR of an object is pegged to any specific property. Tensile strength, compression strength, factoring in toughness etc. If doubling the compressive strength increases DR by a factor of 7.5 do further doublings also increase DR 7.5 times? Or does it level out? Or should DR change per every 5,000 PSI?

Dwarf99 · 01-19-2010, 08:32 PM

Not sure, there may be diminishing returns, then again there may be a square cube relationship.

Joseph Paul · 01-22-2010, 09:22 AM

What I am finding so far shows that other properties like impact resistance and tensile strength are all over the place depending on what test and when it was done compared to the compression test. Some research shows correlation with the compressive strength and others don't. Hmmm.

Dwarf99 · 01-22-2010, 08:03 PM

Compression strength seems the simplest guideline.

Fred Brackin · 01-23-2010, 08:17 AM

Quote:

Originally Posted by Dwarf99

Compression strength seems the simplest guideline.

Yet the thing about composite materials is usually that what starts out as a compression load on the base material turns into a tensile strength load when it meets the reinforcing fibers. That's why high tensile strength fibers are being used as reinforcement.

Is it complicated? Yep. Grown men with advanced degrees spend their working lives on it. Can it be reduced to a rule of thumb for rpg purposes with any degree of accuracy? Probably not.

So if you really feel as though you have to have a rule of thumb use whatever you find simplest.

Joseph Paul · 01-23-2010, 07:16 PM

Woot mon! That leads to high strength concretes in construction at TL9-10 which means that it is cost effective to build hasty and deliberate defensive positions out of the buildings in an urban campaign. My favorite rationale for mechs is resurrected with materials that can resist the attacks of 100mm ETK APEP ammo.

Next material -<Edwin Star voice>Foam steel - What is it good for?</Edwin Star voice>

01-15-2010, 10:50 PM	#1
Joseph Paul Custom User Title Join Date: Oct 2007 Location: Indianapolis, IN	Advanced construction materials Concrete is a wonderous thing. And it may be getting better. Currently there are a couple of different products being used to retro fit existing buildings to make them less susceptible to bombs. Essentially it is a high rupture strength material bonded to the walls. When struck by an explosion the wall may break but it doesn't spew debris into the building. The bonding material helps take up some of the blast energy but more importantly it keeps the wall together to help prevent collapse and more wall coming down. High strength concrete may be getting mixed with carbon fiber to improve its resistance to breakage and there may be more benefits in doing that at the nano level. Anybody got any insights on ball parking such advances in regards to HP and DR? __________________ Joseph Paul

01-16-2010, 05:19 AM	#2
Dwarf99 Join Date: Nov 2006 Location: Fayetteville, Arkansas	Re: Advanced construction materials You'll have to get more information before I can give you a decent answer but I'd say this new stuff is probably ruggedized, and it probably makes HT rolls against collapse. I could be off base... I'm sure that if you can find some stats on the differences in pressure that each type takes to break that ratio would probably be good 'nuff. Also HP would probably be off the HP table in the back of campaigns.

01-16-2010, 11:54 AM	#3
Joseph Paul Custom User Title Join Date: Oct 2007 Location: Indianapolis, IN	Re: Advanced construction materials And that HP and DR increase is what I am looking for. From BigFuture.com - There are higher strength fiber reinforced concretes and geopolymers available. These run in to the 50,000 to 60,000 PSI range. Normal construction grade concrete is 3-5,000 PSI. The Massive Ordnance Penetrator (~30,000 lbs)is designed to penetrate 60 meters of 5,000 PSI concrete and can do 8 meters of 10,000 PSI concrete. That is quite a fall off in performance. If a doubling cuts penetration by a factor of ~7 then 20,000 PSI concrete would stop one with 1.1 meter of material. Why use such strong (and therefore more expensive) materials? Well if you are in the future it may not be all that more expensive to build more resistant structures. In reality there is a brand of concrete with a 14,000 PSI rating getting a lot of use in NYC. Apparently people there want something a little stronger. Higher incidences of natural disasters may be a factor, or providing for currently unknown threats in a new environment, or by having it legislated as the government wants to make sure that buildings can be of use in event of invasion. Under UT firepower (ETC, ETK, APEP etc) buildings are of no use as cover against light ordnance. So given that Basic pegs concrete at DR 12/inch and HP is the cube root of 8 times the mass what should better concrete have? Right now I get a DR 0f 90/inch for the 10,000psi material. I don't know how much denser it may be though for the HP. For the MOP to work in GURPS it needs to deliver 28260 pts of damage to penetrate 60 M. __________________ Joseph Paul Last edited by Joseph Paul; 01-17-2010 at 01:55 PM.

01-17-2010, 11:21 PM	#4
Dwarf99 Join Date: Nov 2006 Location: Fayetteville, Arkansas	Re: Advanced construction materials HP is based on the weight according to Object Hit Points Table and Size and DR of Structures both found on B 558 "typical weights per 1,000 square feet (sf) of area are 50 tons for wood frame or mud brick, 100 tons for steel frame or brick, and 150 tons for stone."

01-18-2010, 08:50 PM	#5
Joseph Paul Custom User Title Join Date: Oct 2007 Location: Indianapolis, IN	Re: Advanced construction materials I get what RAW says about HP. I just don't know if the better quality concretes have a significantly different density. Also if the DR of an object is pegged to any specific property. Tensile strength, compression strength, factoring in toughness etc. If doubling the compressive strength increases DR by a factor of 7.5 do further doublings also increase DR 7.5 times? Or does it level out? Or should DR change per every 5,000 PSI? __________________ Joseph Paul

01-19-2010, 08:32 PM	#6
Dwarf99 Join Date: Nov 2006 Location: Fayetteville, Arkansas	Re: Advanced construction materials Not sure, there may be diminishing returns, then again there may be a square cube relationship.

01-22-2010, 09:22 AM	#7
Joseph Paul Custom User Title Join Date: Oct 2007 Location: Indianapolis, IN	Re: Advanced construction materials What I am finding so far shows that other properties like impact resistance and tensile strength are all over the place depending on what test and when it was done compared to the compression test. Some research shows correlation with the compressive strength and others don't. Hmmm. __________________ Joseph Paul

01-22-2010, 08:03 PM	#8
Dwarf99 Join Date: Nov 2006 Location: Fayetteville, Arkansas	Re: Advanced construction materials Compression strength seems the simplest guideline.

01-23-2010, 07:16 PM	#10
Joseph Paul Custom User Title Join Date: Oct 2007 Location: Indianapolis, IN	Re: Advanced construction materials Woot mon! That leads to high strength concretes in construction at TL9-10 which means that it is cost effective to build hasty and deliberate defensive positions out of the buildings in an urban campaign. My favorite rationale for mechs is resurrected with materials that can resist the attacks of 100mm ETK APEP ammo. Next material -<Edwin Star voice>Foam steel - What is it good for?</Edwin Star voice> __________________ Joseph Paul