concrete foam

Advantages of Using PROVOTON Foam Concrete 1. High strength with low density Typical cast densities range from 25 to 55 pcf, with compressive strengths of 40 to 750 psi, respectively. With its low density, foam concrete imposes little vertical stress on the substructure, a particularly important issue in areas sensitive to settlement. Due to its low density, foam concrete is a viable solution for reducing loading on burdened soil. Additionally, foam concrete is less susceptible to differential settlement. Heavier density foam concrete with higher strengths is produced and used for specialty applications. lightweight backfill, bridge abutment backfill, abutment backfill 2. Rigid, well-bonded body PROVOTON foam concrete forms a rigid, well-bonded body after gelling (hydrating); thus, it is effectively a freestanding structure on its own and does not impose lateral loads on adjacent structures. The material can be constructed into various formations and profiles by forming and stepping of successive lifts. Foam concrete can also be machined to create a desired effect. load reduction, lightweight fill, load reducing, load-reducing 3. No Compaction Required In some cases mechanical compaction can be difficult and unsafe due to limited or inaccessible areas. In excavations with poor soils that are not easily or incapable of being compacted, PROVOTON foam concrete forms a 100% compacted foundation over the soft soils. When compaction of conventional backfill against retaining structures or deep foundations, traditional methods can cause damage or movement to the adjacent structure or just be too time consuming. In these instances, PROVOTON foam concrete is a great solution. lightweight retaining wall backfill, MSE wall backfill, lateral load reduction fill 4. High Fluidity Foam concrete pumps easily with relatively low pressures via hose over long distances. For applications over 4000' such as pipe in tunnel backfill, the slurry is pumped through pipe with the pre-formed foam injected near the point of placement. The material is naturally self-leveling and fills the smallest voids, cavities and seams. When placing in excavations, foam concrete conforms to every sub grade contour.lightweight sub base, foam concrete sub-base, soil stabilization, unsuitable soils, poor underlying soils 5. Rapid Installation High volume production and placement (via hose) of foam concrete is a continuous operation from a mobile central plant on location. Since the foam is the largest volume contributor in foam concrete, limited deliveries of the raw materials are required, which results in minimal disruption to the construction site.

Operational & Cost Efficiencies 1. Settlement Free Construction The principle of equilibrium and the use of PROVOTON foam concrete aims for settlement-free construction. When higher density soils are excavated, they are replaced with foam concrete, so that the combined weight of the foam concrete and the new construction is less than or equal to the weight of the removed soil. Thus the effective stress of the underlying soil has not changed, preventing settlements. tunnel backfill, mine backfill, backfill grout, low density backfill, pipe in tunnel backfill, insulanting concrete 2. Ease of Removal Foam concrete can be designed for specific strengths to allow for future removal for maintenance of utilities or excavation. Sometimes excavation of CLSM or flowable fill materials can be difficult due to unpredictable gains in strength due to delivery and production methods. PROVOTON foam concrete is produced on location to exact requirements, and can be easily excavated with common construction equipment. Freeze/Thaw resistance, foam concrete production equipment, production of foam concrete 3. Time Savings The application of PROVOTON foam concrete can be a great time saver over conventional ground treatment methods for settlement free construction. No waiting period for consolidation of sub soils, eliminating the need for surcharging No need for removal and replacement with large amounts of borrow soils Removal of minimal amount of soil to be replaced with PROVOTON foam concrete Can be applied directly on existing marginal ground such as peat or poor soils Reduce or eliminate the need for piling, sand drains, or grade beams Deeper placement of lifts, due to reduced lateral loading and no compaction steps Eliminate the need to correct completed construction which has settled Energy absorbing material, Foam Generators 4. Cost Savings PROVOTON foam concrete is an economically viable solution, particularly in large volume applications. Its use can also have an effect on other aspects of construction. Mix designs are tailor-made for the project and budget requirements Minimal lateral loading enables reduced building costs for earth retaining structures Construction on marginal ground reducing the need for piled foundations Lower maintenance costs because durability of foam concrete and lack of settlements Innovative methods to correct or prevent subsidence in lieu of expensive treatments High volume equipment with rapid installation reduces installed unit cost Bridge Abutment / Approach Backfi ll Interstate 90, Wasta, SD South Dakota Department of Transportation 1997 Density: 30 pcf - 40 pcf Volume: 8,000 cy Two narrow bridges were replaced with a Contech Super Span arch bridge to eliminate icing conditions on Interstate 90 near Wasta, South  Dakota. Initially, the eastbound lanes’ arch structure was backfi lled with a granular material, but the soft underlying soils began to compress  under the new load, and settlement of the arch bridge footing beam began to occur. Over a four-year period of monitoring, the underlying soils  fi nally consolidated. The granular material was removed to springline of the eastbound arch structure and replaced with PROVOTON foam  concrete to provide a lightweight backfi ll to eliminate future settling of the structure. Once the eastbound lanes were completed, the westbound bridge was removed and replaced with the steel arch structure and backfi lled with PROVOTON foam concrete. The advantages of the lightweight backfi ll will be:  a) Less overburden on the structure and underlying soils.  b) When set, the foam concrete is 100% compacted, and provide a solid support for the structure.  c) Foam concrete is free standing when set, causing no lateral pressures on the structure and the end walls. The project involved replacement of a narrow divided steel girder I - beam bridge structure on the Interstate 90, about 10 miles west of Wall,  South Dakota. This section of highway travels down in elevation through the Cheyenne River Valley. The bridge structures spans a single railroad track that runs through the low point of the valley. The location of the west end of the bridge along the stationing of the westbound lanes  was at the point of tangency of the curve, or the end of the curve. The narrow bridge combined with a slight bank that faced a southern exposure and with the location of the bridge structure, was the site of  numerous accidents. Due to the harsh winters with large snow falls and extreme low temperatures, the SDDOT had diffi culty keeping ice off  the bridge structure. The bridge being narrow and with no shoulders, prevented the snow plows from throwing the snow over the outside  guard rail. The snow that was piled up along the guard rail would begin to melt slightly and the moisture would fl ow across the west bound  lanes and become icy and dangerous. May 2006   v.1.1Their solution was to replace the bridge structure with a Contech Super Span steel plate bridge culvert and backfi lling the structure with a soil  cover. The new bridge structure would be much wider and allow for the addition of shoulders, also with the thick soil cover the road surface  would not be susceptible to freezing as much as the old bridge structure. The approximate size of the Contech Super Span structure was 35’  wide by 27’ tall and covered 320’ of the railway. The project was to be constructed in two stages. First stage was to switch the eastbound traffi c to the westbound lanes and to demo and  replace the eastbound bridge structure. Once the bridge was removed, the concrete footings that the new steel structure would be connected  to were placed. Backfi lling of the steel structure was with a granular material with a soil cover to construct the road structure upon. Soon after the construction of the eastbound roadway, SDDOT Engineers noticed that settlement of the concrete footings supporting the new  steel liner plate structure was beginning to occur.  Due to the settlement which was occurring at the footings of the eastbound lanes, the westbound lanes bridge reconstruction was put on  hold. SDDOT Engineers began monitoring the settlement to determine how much settlement would occur and what period of time it would  take for the settlement of the footings to stop. Monitoring of the settlement was performed over a four year period after the construction of the eastbound lanes, at which time the settlement had stopped. Due to the additional weight of the granular backfi ll adjacent the steel plate structure it was compressing the underlying  weak soils, and causing the 3’ wide by 6’ deep concrete footings to bow and settle into the ground differentially up to 19” from the original top  elevation of the footings when they were constructed. Corrective measures for the eastbound lane structure was to remove the select granular backfi ll material from the top and both sides of the  structure down to springline of the Contech super span arch. Then backfi ll the excavated area with a engineered lightweight foam concrete. A 30 pcf PROVOTON foam concrete was used for backfi lling from springline up to 2’- 4’ above the crown of the structure, the width of the  foam concrete backfi ll was at a 12’ radius from the sides of the super span structure. A 40 pcf PROVOTON foam concrete was placed 2’-  3’deep on top of the 30 pcf material, and then a 1.75’ road structure built upon the engineered fi ll.  Advantages of the PROVOTON foam concrete were primarily it’s mass, being 25% the weight of the granular material reducing possible  settlement. The minimum compressive strength of the   30 pcf and 40 pcf foam concrete was specifi ed at 80psi and 120psi respectively,  actual breaks of the 30 pcf were 80psi at 7 days and 160psi at 28 days, the 40 pcf material averaged over 300 psi at 28 days. Secondly,  when the foam concrete sets after placement (approx. 4-6 hours) it becomes a free standing mass which will not place lateral loading on the  steel structure. Bridge Abutment / Approach Backfi llThe PROVOTON foam concrete was placed in two foot lifts, one lift per each side of the structure per day which insured that the backfi ll would  not deform the steel structure during the backfi ll. Outside 2’ high forms were relocated 4’’ in towards the steel structure on top of the previous days pour for the next lift that day. Once completed with the foam concrete backfi ll the road structure was constructed and the two way traffi c switched from the west bound lanes to the  east bound lanes.  Demolition began on the original west bound lanes bridge structure and the construction of the west side Contech super span arch was  started. Once the arch was constructed, select granular backfi ll was placed up to springline on both sides of the arch, (approximately 10’) .  The foam concrete backfi ll was placed in the same manner as the east bound structure. Along with backfi lling the arch, bin walls which help  stabilize the northwest slope of the project were backfi lled with foam concrete to reduce the overburden. Over 7000 cy of the 30 pcf, and 1400 cy of the 40 pcf PROVOTON foam concrete was placed during the From: Concrete Construction January 2005   Posted on: January 17, 2006 Features Finishing Lightweight Air-Entrained Concrete No problem if you follow standard practice By: Joe Nasvik 1 Comment Share   Lightweight-aggregate, air-entrained concrete is increasingly used to cast interior, above-grade floors. There are two principal reasons for its use: cost savings and fire resistance. According to John Ries, executive director of the Expanded Shale, Clay and Slate Institute (ESCSI), Salt Lake City, lightweight concrete floors are typically 25% to 35% lighter than regular concrete aggregate mixes, so there can be considerable cost savings realized by designing longer span floors with lighter structural members. Lightweight concrete slabs can also be significantly thinner than ordinary aggregate mixes and still achieve equivalent fire ratings. Jack Gibbons, director of technical services for Central Readymix, Milwaukee, says that nothing has really changed in the science of lightweight aggregate concrete mixes. The same time-honored rules apply to placing and finishing. When to begin finishing is the most critical issue. Using newer equipment and technology, contractors will sometimes assume they can start finishing slabs earlier. The advent of “pan” floats makes it possible to begin finishing operations before the concrete is sufficiently firm. This can cause surface regions of a slab to be more compacted. Gibbons reports petrographic studies showing compacted surfaces of ½ to ¾ inch deep, when ? to ¼ inch is normal for properly timed and finished concrete floors. The other potential problem involves the use of riding power trowels, even though they are often used successfully on lightweight concrete. These trowels can weigh from 620 to 2200 pounds, not including the weight of the operator. With that amount of concentrated load, they can deflect the metal deck under the concrete and are capable of producing overly compacted surface finishes—sometimes down to half the thickness of a slab. Deeper compaction due to early finishing could lead to delamination. Lightweight aggregate mixes— high air, high slump The primary reason for using lightweight concrete on a deck is to lighten the load on the structure. Gibbons says that most specifications require mixes with unit weights of 110 to 115 pounds per cubic foot at equilibrium (weight after a sufficient interval of drying, when the relative humidity of the concrete reaches that of ambient conditions). “You can't achieve these equilibrium densities with aggregates alone,” he says. “Adding air entrainment in the range of 6% to 7.5% (and sometimes higher) is needed in order to meet specified weights.” So the adage that you shouldn't use a power trowel on air-entrained concrete doesn't apply in the case of lightweight concrete; you can use a power trowel, but only with proper timing. A typical fire-rated lightweight mix calls for compressive strengths between 3500 and 4000 psi. Gibbons says that most lightweight concrete is pumped, with 4000-psi mixes being favored. The aggregates are generally ¾ inch minus and must be saturated with water before mixing. Gibbons orders pre-soaked material and then keeps a water sprinkler running over the aggregate pile. Cementitious content is typically 564 pounds per cubic yard (6 bags of cement). Slump at the pump may be as much as 8 inches in order to facilitate pumping. Normally one might expect more shrinkage and curling resulting from these mix proportions, but Gibbons says there are minimal problems. This is because the mix water not required for hydration leaves the slab slowly, resulting in well-cured concrete. Lightweight mixes are normally used for new construction, and the slabs are generally covered with carpeting. Five or 6 months can elapse from construction to the installation of finished flooring, providing time for excess moisture to leave slabs. Carpeting is the most frequently used covering, and it provides adequate moisture vapor transmission. When finished surface products that are sensitive to moisture are installed, slab relative humidity should be monitored carefully. Timing is everything Although pan floats and riding trowels make it possible to start finishing earlier, they also increase the risk of delamination. Common finishing procedures are still the best. Pete Valek, superintendent for Lindblad Construction, Joliet, Ill., has these tips for lightweight deck placements: Notify your ready-mix producer several days before you need concrete so there is time to stock the aggregate and pre-soak it. The pores in aggregate should be adequately filled. After placement, wait for all bleed water sheen to disappear from the surface of the concrete before starting floating operations. When you step on the fresh concrete, your footprint indentation shouldn't go deeper than ? to ¼ inch. To be safe, use walk-behind finishing machines instead of ride-on machines. Again, for safety, use float pads on your finishing machines rather than pan floats. Don't “burn” the finish. Lightweight floors are almost always covered with carpet, so over-finishing is unnecessary and increases the risk of problems. Floor flatness and hard troweling issues Bob Simonelli, a floor finishing consultant for Structural Services Inc., Dallas, says that he occasionally consults with clients who have specified floor flatness tolerances of FF30 or 35 (FF25 is a more reasonable specification) with hard-trowel finishes. He says these requirements escalate the risk for possible delamination, so greater attention to the timing and details of finishing must be observed. He advises clients to use a walk-behind trowel with float pads for the first finishing step. The next step is switching to pan floats, which may be mounted on riding trowel machines. Final troweling operations are completed with riding trowels. “It's very difficult to achieve higher FF requirements without the use of riding trowels,” Simonelli says. Summary There are many advantages associated with lightweight floors, especially on metal decks, but there is also a potential for delamination. The timing of finishing steps is the critical element—especially when the use of pan floats and riding trowels is planned. Simonelli urges pre-job meetings with owner's representatives, specifiers, and material suppliers. Concrete Surfaces Hot Topics:  World of Concrete  CC100  Most Innovative Products Services:  Buyer's Guide  WOC Bookstore  Sponsor Video Gallery   From: Concrete Construction March 2011   Posted on: March 8, 2011 Concrete Surfaces | Feature Dressing Up Stairs Even novices can create beautiful concrete stairs. By: Keith Boudart Be the first to comment Share   Credit: Butterfield Color These stairs were created with a formlinera user-friendly, innovative way to create natural-looking decorative concrete stairs. Enlarge Credit: Butterfield Color These stairs were created with a formlinera user-friendly, innovative way to create natural-looking decorative concrete stairs. The world of decorative concrete has grown tremendously over the past decade. The innovations and new products have allowed the market to expand to areas very few expected. One area that has developed in both craftsmanship and innovation is concrete steps. Although dressing up stairs has been around for some time, new tools and techniques allow both novice and experienced contractors to differentiate themselves, and most importantly, increase their bottom line. Decorative concrete stair methods can be broken out into decorative formliners, strip and face, and decorative overlays. These methods are unique and have the ability to create an attractive focal point. Step formliner The step formliner is the most user-friendly and innovative way to create natural looking decorative concrete stairs. Foam formliners have been around for a while, but a newer method of using urethane liners has taken a giant leap over the past few years. Several different options are now available, but the most prevalent is using a bull nose or cut stone liner in the face of the stair risers. Step formliners make the process a bit easier as they don’t require you to strip the forms the same day as pouring and they do not require the standard 28-day cure time when dealing with overlays. Another key advantage with step formliners is they can be easily used with radius stairs. Formliners require a bit of extra forming but nothing too extraordinary. Step liners come in many shapes and sizes but are most commonly used to create a cantilevered step along with a textured riser. Some manufacturers also offer a cantilevered option built into the liner to ease the process. Also available are riser liners to use under the cantilevered portion of the stairs. Often the stairs are poured with the liners, vibrated, and cured overnight. Once stripped, the next day contractors will use release agents, stains, and color hardeners to accent the textured areas. The nice thing about formliners is they work seamlessly with radius steps, create a very natural stone or slate look, and add minimal additional costs. Strip and face Strip and face is the most common method of creating decorative concrete stairs and has been around for the longest period of time. It also is the same method that is used in nondecorative applications. This method usually is performed immediately after the concrete has set enough so the riser forms can be removed without damaging the formed concrete. This is commonly practiced with stairs and is performed to ensure there are no bug holes or honey combing in the face of the risers. The forms are carefully removed once they are stable enough not to cause any sag. Then the stairs are rubbed out with a rubber float, magnesium float or trowel. Sometimes the contractor may add a decorative finish by leaving a swirl finish or just a rough finish with the float. This is the same method that has been used by decorative concrete contactors for years to create decorative stairs. Once the stair forms are removed he uses color hardener to color both the tread and the risers with a float. Often the contractor will sift out some of the larger aggregate from the color hardener before beginning the application. Once colored, a release agent is applied to both tread and riser, and a textured stamp creates a natural looking stone or slate. Some contractors wait until the next day to remove the forms, apply a bonding agent to the surface and follow the same procedures using color hardeners and releases to create a natural pattern on the stairs. Also, some manufacturers make color hardeners to match their integral color systems. The advantage: Concrete can be poured with integral color and the matching color hardener colors the front of the risers once the forms are stripped. Overlays Polymer-modified, cement-based overlays create a colored, textured surface. Two main types of overlays create decorative stairs: spray overlay and stamp overlay. Several manufacturers make both types and with most, the concrete must be fully cured before application. The spray overlay is used with a hopper gun to create a splatter or knockdown finish. Most of the spray overlays can be colored, stained, and used with stencils to create a decorative look. With the stamp overlay a color complements the decorative nature of the existing concrete and is then applied to both the tread and the riser. A release agent and stamp are then used to create the desired look. Keith Boudart is sales manager with Butterfield Color Inc. Visit www.butterfieldcolor.com. Visitwww.concretesurfacesmag.com to view video of Butterfield Color’s Contractor Clinic presentation at World of Concrete. Residential Projects Hot Topics:  World of Concrete  CC100  Most Innovative Products Services:  Buyer's Guide  WOC Bookstore  Sponsor Video Gallery   From: Concrete Construction February 2012   Posted on: February 3, 2012 Feature ICFs + Removable THis home builder took advantage of the benefits of each system. By: Joe Nasvik Be the first to comment Share   In the scenic country between Springfield and Branson, Mo., a 72,000-square-foot concrete house, currently under construction, will be one of the largest single-family homes in the United States once completed. The owner and designer, Steven Huff, says Pensmore will be a second home for his family and a place for charitable organizations and universities to gather for conferences and meetings. However, the house also is being constructed to prove the efficacy of a new forming system for concrete walls. Kirk Brown, CEO of TF Forming Systems, Green Bay, Wis., says he and Huff bought the company because they thought this new concept for forming concrete walls had merit. After making several changes to the system, they cast test panels two years ago and on the strength of those results decided to cast all the structural walls of the house using the system, continuing to make refinements to form elements as they went along. A hybrid ICF system One reason that concrete buildings are energy efficient is the thermal mass of concrete walls. Energy, or the lack of energy, can be stored in walls and floors to play a part in heating and cooling, reducing overall energy consumption while moderating temperatures. This means concrete walls must be isolated from outside ambient conditions but exposed to the inside environment. To accomplish this, Gerald Spude, the founder of TF Forming Systems, converted Huff and Brown’s ideas for the formwork into a practical, working system. The TF forming system is different than a typical ICF system where the foam insulation thickness is equal on both the inside and outside of a wall, and is strong enough to resist form pressures during concrete placement. The TF (or TransFrom) System has 4- or 5-inch-thick rigid foam insulation on the outside of the wall, serving as the form panel during construction and insulation for the wall afterward. But the inside wall surface is covered by only a 3/4-inch-thick rigid foam insulation panel. This thin panel dampens thermal transfer while still making it possible to use the concrete as a heat sink for the interior heating and cooling of rooms. Brown contends that walls are a better location for radiant heating and cooling than floors, so for the Pensmore project, they are installing PEX tubing at the center of all exterior concrete walls. To achieve a net-zero energy balance, fluid circulating through panels mounted on the roof will be heated by the sun during the winter, sending it through the PEX tubing in the walls to heat the house. During the summer, fluid circulated through underground piping will be cooled by the earth to 55º F and circulated in the walls to provide cooling. Structural form elements At the heart of the TF System is polyvinyl chloride (PVC) recycled plastic studs, or rails, with built-in channels. Workers set the studs in position on 16-inch centers just as they would if they were erecting a wood wall. There is a stud wall support system for the inside and another for the outside. Both support systems become a permanent part of the wall after concrete is placed. When the exterior studs are in place, workers insert the thick foam insulation panels into channels on the studs that hold them in position. They become the form panel for the concrete and the exterior flange of the studs becomes the point of attachment for the exterior finish system. The inside wall-forming system is more complicated. The PVC studs feature two sets of channels: one to hold the 3/4-inch-thick insulation panels in place and the other to position PVC panels that strengthen the insulation sheets and resist the forces of freshly placed concrete. The PVC removable form panels are supported by strong-backs to keep the wall surfaces flat and straight, and also serve as the inside attachment for wall ties, scaffolding, wales, and braces. When the PVC panels and strong-backs are removed afterward, a 3 1/2-inch void is created, providing a chase for pipes, electrical boxes, conduit, and wiring for phones, televisions, computers, and other electronics. The inside flange is used to secure drywall and other interior finishes. The forming system depends on form ties connected to the inside and outside forms. Brown says the ties can be any length in order to accommodate the required or desired wall thickness. He adds that inside and outside forms don’t need to be installed at the same time, making it easy to install reinforcement, PEX tubing, and other inserts. Placing concrete Concrete for the project includes steel fibers in the mix for added strength and the addition of a superplasticizer to make it easier to pump. Workers at Pensmore place concrete for walls in 16-foot vertical lifts, using internal vibrators for consolidation. The robust forming system eliminated blowouts and deformed wall surfaces—the same result one would expect from any good form panel system. The concrete floors (decks) at Pensmore are constructed with a standard steel joist system with pan deck forms that are easily connecting to the walls. Workers place concrete for each floor deck after the walls are completed. This allows them to do all the bracing for the next level of wall forms on the inside of the structure. Pensmore today Workers have completed 70 vertical feet of walls with no deformations. Concrete work on the building will be complete this spring and the roof will be in place by the end of 2012. Brown believes this building system will result in 50% to 60% more energy efficiency than timber frame wall construction, enabling them to achieve 100% efficiency with their roof-mounted hot-water system. The goal is to have a very green and healthy living environment—using all recycled plastic, reusable forming hardware, almost no wood in the structure (a food source for mold), and producing little construction waste. To learn more about the construction of this house, visit www.pensmore.com. To learn more about the TransForm wall forming system, visit www.tfsystem.com.