Ferro Cement Hulls ?

[CaptainK]

Hey Wheels,

I believe your last post that had this address:

http://www.ferrocementmethods.org/2.html

Seems to be a bad link. Or that their servers down?

Maybe you should check their website again. And then, see if it's a wrong link. Or confirm that their server is down?

I'm interested in what you have to show all of us here in this forum?

[Alan Wheeler]

Thanks for the heads up on that cpt K. I may have copied it wrong. Here is the link to the site and just navagate around. It is interesting.
www.ferroboats.comhttp://www.ferroboats.com

[CaptainK]

Dear Wheeler,

I have this website bookmarked in my "favorite places," folders.
Great website. I was going to purchase some books from them. Til after I joined this forum, and made me change my mind?

Unless somebody can convince me otherwise. I was wanting to build a ferrocement hull at first. Then, I think Wheels and probably somebody else suggested to buy a abandon boat project ferro hull. And go from there. But, buying someelse's ferro hull. Probably would be a major headache. Due to them not building it right?

We'll see what happens?

[Talbot]

I believe there is one fundamental rule about buying a S/H ferro boat - only buy one that had the hull done professionally by repurtable builders, preferably to a Lloyds standard.

[CaptainK]

I agree, Talbot.

If I would have to buy a used ferro hull from anyone. I would buy one that has been built to professional standards. Like Lloyds. And other standards equal to Lloyds!!

[Talbot]

Wheels,

just had a quick look at your link and after having looked at the pi-in-the-poke stuff, after falling down laughing at a couple of the "designs", the picture of the "concrete worms" caught my eye.

This blamed the problems on salt in the sand. I immediedlty thought that this might be the fundamental point.

In UK most of the sand (especially close to the coast) is recovered from the sea, and even after washing is normally still saturated in salt. I have only been to NZ once but should think that from what I saw then, most of your sand is recovered from land sites.

Where does the sand come from in USA?

Perhaps this is why NZ ferros have a much better reputation?

[CaptainK]

I believe that the sources of clean sand, comes from the rivers of the United States?

Other sources are probably from other areas, besides the beaches of the United States?

The majority of the sand pits in Ca and Or are near coastal areas. Certainly close enough that salt intrusion would me measurable. This includes Portland Or. It really could be one of the issues with different quality. In addition to this, I think Wheels' comment about sulphate resistant cement is very telling. It would be interesting to compare a hull built in 1980 to one built in 2000.

[CaptainK]

Types of Portland Cement
Different types of portland cement are manufactured to meet various physical and chemical requirements. The American Society for Testing and Materials (ASTM) Specification C-150 provides for eight types of portland cement.Type I portland cement is a normal, general-purpose cement suitable for all uses. It is used in general construction projects such as buildings, bridges, floors, pavements, and other precast concrete products. Type IA portland cement is similar to Type I with the addition of air-entraining properties. Type II portland cement generates less heat at a slower rate and has a moderate resistance to sulfate attack. Type IIA portland cement is identical to Type II and produces air-entrained concrete. Type III portland cement is a high-early-strength cement and causes concrete to set and gain strength rapidly. Type III is chemically and physically similar to Type I, except that its particles have been ground finer. Type IIIA is an air-entraining, high-early-strength cement. Type IV portland cement has a low heat of hydration and develops strength at a slower rate than other cement types, making it ideal for use in dams and other massive concrete structures where there is little chance for heat to escape. Type V portland cement is used only in concrete structures that will be exposed to severe sulfate action, principally where concrete is exposed to soil and groundwater with a high sulfate content.

Portland cements can also be made to ASTM C1157 and include the following: Type GU hydraulic cement for general construction, Type HE-high-early-strength cement, Type MS-moderate sulfate resistant cement, Type HS-high sulfate resistant cement, Type MH-moderate heat of hydration cement, and Type LH-low heat of hydration cement. These cements can also be designated for low reactivity (option R) with alkali-reactive aggregates.

White Portland Cement
In addition to the eight types of portland cement, a number of special purpose hydraulic cements are manufactured. Among these is white portland cement. White portland cement is identical to gray portland cement except in color. During the manufacturing process, manufacturers select raw materials that contain only negligible amounts of iron and magnesium oxides, the substances that give gray cement its color. White cement is used whenever architectural considerations specify white or colored concrete or mortar.

Blended Hydraulic Cements
Blended hydraulic cements are produced by intimately blending two or more types of cementitious material. Primary blending materials are portland cement, ground granulated blast-furnace slag, fly ash, natural pozzolans, and silica fume. These cements are commonly used in the same manner as portland cements. Blended hydraulic cements conform to the requirements of ASTM C595 or C1157. ASTM C595 cements are as follows: Type IS-portland blast-furnace slag cement, Type IP and Type P-portland-pozzolan cement, Type S-slag cement, Type I (PM)-pozzolan modified portland cement, and Type I (SM)-slag modified portland cement. The blast-furnace slag content of Type IS is between 25 percent and 70 percent by mass. The pozzolan content of Types IP and P is between 15 percent and 40 percent by mass of the blended cement. Type I (PM) contains less than 15 percent pozzolan. Type S contains at least 70 percent slag by mass. Type I (SM) contains less than 25 percent slag by mass. The supplementary materials in these cements are explained further on page 28. These blended cements may also be designated as air-entraining, moderate sulfate resistant, or with moderate or low heat of hydration. ASTM C1157 blended hydraulic cements include the following: Type GU-blended hydraulic cement for general construction, Type HE-high-early-strength cement, Type MS-moderate sulfate resistant cement, Type HS-high sulfate resistant cement, Type MH-moderate heat of hydration cement, and Type LH-low heat of hydration cement. These cements can also be designated for low reactivity (option R) with alkali-reactive aggregates. There are no restrictions as to the composition of the C1157 cements. The manufacturer can optimize ingredients, such as pozzolans and slags, to optimize for particular concrete properties. The most common blended cements available are Types IP and IS. The United States uses a relatively small amount of blended cement compared to countries in Europe or Asia. However, this may change with consumer demands for products with specific properties, along with environmental and energy concerns.

Expansive Cements
Expansive cements are hydraulic cements that expand slightly during the early hardening period after setting. They meet the requirements of ASTM C845 in which it is designated as Type E-1. Although three varieties of expansive cement are designated in the standard as K, M, and S, only K is available in the United States. Type E-1 (K) contains portland cement, anhydrous tetracalcium trialuminosulfate, calcium sulfate, and uncombined calcium oxide (lime). Expansive cement is used to make shrinkage-compensating concrete that is used (1) to compensate for volume decrease due to drying shrinkage, (2) to induce tensile stress in reinforcement, and (3) to stabilize long-term dimensions of post-tensioned concrete structures. One of the major advantages of using expansive cement is in the control and reduction of drying-shrinkage cracks. In recent years, shrinkage-compensating concrete has been of particular interest in bridge deck construction, where crack development must be minimized.

[CaptainK]

Sulphate resistant cement


Sulphate resistant cement – designed for aggressive environments

A cement with enhanced sulphate resistance

The sulphate resistant cement (SVC III/A 32,5 R) was launched into the Czech market in August 2001. In Czech Republic European harmonized standards for cements EN 197-1 are valid since March 2002. From March 2004 - as a preparation for joining European Union - marking of sulphate resistant cement has been changed to CEM III/A 32,5 R – svc.

This cement is especially for aggressive environments. The concrete made from this cement is typically used in foundations, basements, and waste-water systems as well as for standard ready mixed concrete. The composition of this cement is different than the average cement due to the limited content of calcium aluminate in the clinker and limited content of clinker in cement. This is significant for limiting the reaction between tricalcium aluminate (C3A) and sulphate which damages concrete. The portland clinker within sulphate resistant cement is specifically produced at Cement Works Mokra for this product and for special cement being used for concrete roads.


Sulphate resistant concrete is designed for aggressive and corrosive environments. The biggest customers are large ready-mix companies and the manufacturers of pre-cast elements such as pipes. Currently, there are no European standards for sulphate resistant cement. For this reason, sulphate resistant cement CEM III/A 32,5 R is being produced, certified and brought to the Czech market according to general European harmonized standard for cements EN 197-1 and according to tighten requirements.

For more details regarding technical characteristics and application of CEM III/A 32,5 R please get in contact with...

Contact:

Ceskomoravsky Cement

www.cmcem.cz

[CaptainK]

Sulphate-Resistant Portland Cement Type 50

Type 50 Portland cement is used only in concrete exposed to severe sulphate action - principally where soils or groundwaters have a high sulphate content.

It gains strength more slowly than Type 10, Normal cement. The high sulphate resistance of Type 50 cement is attributed to a low tricalcium aluminate (C3A) content, not more than 3.5%. Use of a low water to cementing materials ratio and low permeability are critical to the performance of any concrete exposed to sulphates. Even Type 50 cement concrete cannot withstand a severe sulphate exposure if the concrete has a high water to cementing materials ratio. Type 50 cement, like other portland cements, is not resistant to acids and other highly corrosive substances. The chemical and physical requirements for Type 50 cement are given in CSA A5.


Sulphate resistance also increases with proper air entrainment and decreasing water-cementing materials ratio.

References:
Durability of Concrete in Sulfate-Rich Soils # code RD097.T
Long-Time Study of Concrete Durability in Sulfate Soils # code RD086.T

Cement Association of Canada

[Alan Wheeler]

Wow, and I just thought Cement was Cement. Thanks for the time you have taken to supply that great detail CptK.
Well Folks. I have a feeling that between the sand and the cement, an answer may be.
The sand we use here in NZ is river sand. It is mostly a dark grey Granite. Fine silt is washed out and the sand tends to be sharp. This allows for a tight strong interlocking nature of the Plaster mixture. Beach sand would be too round or dull and very inconsistant in material around the country.
I have never thought of that till just now. Granite. What an amazing material to build concrete with. Now add to that the type of cement we have here in NZ and maybe, just maybe, we have a very high quaility concrete that the hulls were built from.
It does show one area of concern. The ability for some amature to make a truely strong hull and another to make a weak one, is partly due to a simple lack of understanding of cement and sand. I could just imagine the builder goes off to his local hardware and buys sand and cement. I am sure it would never enter most peoples mind that there would be any differences.

[CaptainK]

Well Wheels,

Sometimes you have to dig into the website google.com . And that site has the most links to whatever you want to find out, about things. Including cement.

That's my main resource provider. With google. I on't know how much harder it would be to find out about certain things?

[BC Mike]

There is sand North of Wenachee off Highway 97 in Washington State. I always wondered what it was doing there. But it is the South exit route for the ice and rivers from the end of the ice age.
Further North in BC you can see where the ice has scraped the sides of rock bluffs. The cement in NZ comes from a plant near Whangarei which is 80 miles North of Auckland.
Michael

I am aware of the quarries you refer to up off of 97, and the sand is very different to that from the coastl quarries. That area is vlcanic, and the sand reflects that. Since the majority of FC hulls are built near the water in consideration of launching costs it stands to reason that the sand comes from coastal sources. As I am not familiar with NZ, I do not know if there are any coastal sand pits there, but there certainly are here. Any sand purchased in the past 20+ years, in the San Francisco, or Monterey Bay areas comes from a few locations. All Coastal. But I digress, my question was about the cement. I am sure that NZ has it's own source for cement, and probably it's own formulation. I suspect this is more directly related to the quality of the finish product, than the sand, or it's salt content.