Bituminous Grout Usage on Shoreline

Get a marine engineer quickily

Why do you want a rigid breakwater ?? - part of the power of a breakwater is to be somehwat flexible as the whole thing move with the design swell/wave

Grouting everything in place disallows inflow/outflow of the swell into the matrix of the breakwater and renders it as a solid wall with considerable greater strength requirements, foundations, etc. to resist the design swell's direct slam...

Need alot more facts to see why you want to make rigid a rip-rap breakwater...has it failed as it is??

Tom Williams

Thanks for your comments. This is a shoreline along Lake Ponchartrain that has had large riprap placed - about 4 miles - which was totally destroyed by Katrina. The rip rap was hurled against the levee and floodwall system and broke through. Essentially, there were previous riprap/solid grout put in about 55 years ago and this withstood the surge. The Corps has recommended the use of bituminous grout in a technical bulletin issued in 1986. They confirmed that there are no other bulletins on this subject. My concern is whether there are environmental concerns that need to be addressed.

This is not a true "breakwater" as it is more of an armoring of the shoreline to prevent erosion of the rip rap and shoreline along the bike path of the lake. This is on the waterside of an 18 foot levee with a 4 foot flood wall on top of it. The storm surge at this site was in exess of 16 feet and totally destroyed the "loose" rip rap that had been in place prior to the storm.

Pretty powerful forces at work here.

Thanks again

Randy Bostrum

I am sorry but I would get a certified engineer to look at this. I haven't heard 'pitch', a tar like substance called Bitumen anywhere outside the Hebrew scriptures. King James translates "Bitumen" as "Slime". It is a very ancient method of water proofing boats. I've never heard of it being used to build a breakwater or as a grout.

The ancient world didn't have a way to refine tar or bitumen. I would contact the EPA before I'd contact the Army Corps of Engineers.

I managed a hotel in Florida and beach erosion was always a problem. The hotel was located oceanside at 176th Street and Collins Avenue and I managed it from 1988 to 1994 when it was sold to developers. Now the Pinnacle condos stands on the site.

What the Army corps did was go out to sea about a mile, dredge up the sand from the bottom and transport it back to the beach. They used bulldozers to spread the new sand and, in so doing, cracked every hotel swimming pool from Hullover beach, at 163rd Street to 197th street - and there wasn't a darn thing you could do about it.

I can't see using Bitumen as a sealant or a grout. Look into hydraulic cement. It's a mixture of quick lime and porous volcanic rock. When it meets up with salt water it hardens into stone - a Roman invention. The entire harbor at Caeseria Maritima in Israel was built by Herod. He built the harbor there precisely because everyone said it was impossible; strong ocean currents and prone to sudden squalls. Herod did it anyway. That harbor can still be seen today with a short dive just off shore.

Bitumen gets soft in the sun, it leaches into the water and, in the ancient world it wasn't meant for long term use without regular reapplication. That's why I want to hear what the EPA says about it.

Sometimes history can teach something new.

Thanks for the post and keep us posted; we don't always work fast but we always persevere.

BTW, how did you hear about CR4? (Just my own personal curiosity).

Good Luck

Orpheuse

Thanks for the comments... great lead on the use of Herod's cement. The only issue with use of a hard "grout" is the continuous cracking from shifting soft ground under the rip rap. The hard concrete tends to crack, water and wave action can then shift the rip rap and undermine the protective barrier. When a hurricane surge occurs the cracked sections can become large missiles. The bituminous grout that was in place has withstood numerous storms and even held up for Katrina.

Our concern is whether this is a permitted substance "under water" for these modern times. We have recieved an Army technical bulletin recommending this material, but - although still current - it was written in 1986.

I used to be involved at projects in Hanford WA and used CR4 for a tremendous technical resource back then. When I searched for anything on this issue I came across your forum again and appreciate all the help.

Thanks

Randy Bostrum

Do a little research on the building of the harbor at Ceasaria Maritima. The location has a great deal in common with the situation you are dealing with.

The currents are dreadful and the shifting sand didn't help. Using the Roman method, Herod built huge barges with screens on the bottom. These were placed in the water empty, so they could be floated into place. Once on the spot they would be filled with slurry and, naturally, they sank. After a short while the Pumice, quicklime and seawater harden. The wood that the barges were made of became "the mortar" which, because it was wood, also made the individual stones, which weigh up to hundreds of tons, slightly flexible. This is an important feature because the man- made harbor remained stable in a major earth quake zone.

The moment you brought up Bitumen, this darn thing won't leave me alone.

That's my ancient $0.02.

good luck and keep us posted.

Thanks

Ari (orpheuse)

Thanks for your advice and history lesson. Herod was an amazing builder - just not good at public relations and "reading people". At this juncture in our project the "owner" is engaging a Marine Engineer to determine the "best" materials for the stabilization of rip rap. I should get an update in a few days and will let you all know what their recommendation is. FYI the US Army Corps of Engineers is using the bituminous grout on a protective breakwater for their flood gates adjacent to the shoreline we are involved with.

Thanks

Randy