Ultimate Home Design – June 2008
Synopsis
The project’s concrete mixes use Portland Cerment, Kryton’s KIM admixture, Euclid Eucon A+ admixture, and 40 percent fly ash.
Waterproofing was one of the most important factors when dealing with the super saturated clay soils, which are prevalent at the building site.
Ultimate Home Design Concept
With respect to home design, the idea is to design and build homes that have no physical barries, thus sustaining people of all ages and all capabilities in a functional, comfortable, and aesthetic lifestyle. The goal is to optimize occupant health, comfort, and safety; maximize energy efficiency and structural durability; and minimize environmental impact. In addition, the aim is toward providing a nurturing home environment to support independent living and sustainable lifestyles.
Completion of the home is anticipanted for Decemeber 2008. It is our intent to produce a high-defination documentary for educational use by the U.S. Green Building Council, the organization who created the LEED for Homes reveal the step-by-step process for creating the first Optimum Performance Home – expected to be one of the highest rated, if not the highest, LEED for Homes Platinum residential home in the world!
This Issue
Doug has designed two other concrete mixes for the project: standard foundation footing and the concrete to be poured into the Amvic ICFs, and the suspended slab-on-grade. These mixes use Portland Cement, Kryton’s KIM admixture, Euclid Eucon A+ admixture, and 40 percent fly ash. The mix design for the standard foundation footings used 324 pounds of Portland Cement, 216 pounds of fly ash (40 percent), 11 pounds of KIM admixture, and 16 ounces of Eucon A+ admixture per cubic yard. The suspended slabon-grade mix design will use, per cubic yard, 360 pounds of Portland Cement and 240 pounds of fly ash (40 percent), 11 pounds of KIM admixture, 18 ounces of Eucon A+ admixture, and FORTA® FERRO®. The Amvic ICF concrete mix design will use the mix design that was used for the standard foundation footings.
Doug has designed two other concrete mixes for the project: standard foundation footing and the concrete to be poured into the Amvic ICFs, and the suspended slab-on-grade. These mixes use Portland Cement, Kryton’s KIM admixture, Euclid Eucon A+ admixture, and 40 percent fly ash. The mix design for the standard foundation footings used 324 pounds of Portland Cement, 216 pounds of fly ash (40 percent), 11 pounds of KIM admixture, and 16 ounces of Eucon A+ admixture per cubic yard. The suspended slabon-grade mix design will use, per cubic yard, 360 pounds of Portland Cement and 240 pounds of fly ash (40 percent), 11 pounds of KIM admixture, 18 ounces of Eucon A+ admixture, and FORTA® FERRO®. The Amvic ICF concrete mix design will use the mix design that was used for the standard foundation footings.
One of the unique features, which has caused quite a bit of frustration during the design phases of the Optimum Performance Home, is the naturally occurring subgrade water, which can be typical in California’s coastal areas. Special design considerations were implemented to take an
otherwise user-unfriendly building site and making it part of the Optimum Performance Home’s unique character.
Waterproofing was one of the most important factors when dealing with the super saturated clay soils, which are prevalent at the building site. The overexcavated-base rock-bearing foundation and the suspended slab footings are only the first part in a very detailed waterproofing system that uses the most advanced technologies to insure that moisture will stay outside of the building envelope where it belongs. Each individual part of the waterproofing system puts its own unique fingerprint on the other parts in the system and has had our suppliers and engineers working overtime to come up with solutions at every turned page of the plans or specification detail.
The most recent change has come in the concrete mix design for the suspended slab-on-grade. Originally designed at 5.50 sack with 30 percent fly ash replacement, as well as Kryton’s KIM waterproofing admixture and Euclids Eucon A+ water reducer (see Note 1), a change has been made to decrease the water-to-cement ratio down to a 0.45 water-to-cement ratio, which will help accommodate some of the design features of the DELTA MS UNDERSLAB waterproofing and vapor-retarding system—one of the more critical features of our Integrated Water Proofing System.
The reason for this change is as much due to the superior vapor-retarding capabilities of the DELTA product as it is to concrete’s ability to be permeable. As discussed in an earlier article in this series, as concrete is being poured, water tends to collect on the surface as particles settle (also known as bleeding). The impermeable nature of vapor retarders in general has a couple of effects. They can decrease the amount of water that enters from beneath the slab and they hold water inside the barrier, which contributes toincreased curing for the concrete. The only problem that may occur, and the reason for the decrease in the water-to-cement ratio to 0.45, is the additional bleed water that may have to come out through the top of the concrete, due to the vapor retarder’s ability to keep the water out as well as in.
The waffle makeup of the DELTA MS UNDERSLAB product will allow areas for the water to go during initial placement, which will decrease the bleeding concerns. To further reduce the permeability of the concrete, and to insure additional protection in the very wet environment, we increased the percentage of fly ash (see Doug Yeggy’s “High Volume Fly Ash—A Tool For The Concrete Designer’s Toolbelt” in Part XIV), which reduces the water of convenience (water needed to place concrete) and the percentage of permeable voids, and is reflected by areduction in bleed water channels, which is the road that allows water to transfer through concrete.
Note 1—We were originally going to submit the 5.50 sack 30 percent fly ash mix and plead our case for the innovation point in the LEED point system. Consideration should have been made by the fact that 360 pounds of cement is the minimum amount that should be used in slab-on-grade concrete to facilitate placing and finishing in a timely manner without having to 1) increase the total cementitious content by one sack or more or 2) use chemical admixtures that would increase the cost of the concrete by as much or more than if we added the previously referred extra sack of cementitious material, and 3) incur greater costs by the contractor in man-hours needed to wait until the concrete was ready to be finish troweled. However, in looking at what was done to meet the LEED requirement for innovation, which is now met with our suspended slab-ongrade mix design, it does seem somewhat foolish that we did nothing more than increase the amount of fly ash by 10 percent over the original 5.50 sack 30 percent mix, which did not meet LEED requirements for an innovation point.
KIM admixture renders hardened concrete impermeable to water penetration, reduces drying shrinkage, protects steel rebar reinforcements from corrosion, and improves concrete durability. The advanced integral crystalline chemicals in the KIM admixture react with water and unhydrated Portland Cement particles to form millions of needle-like crystals to permanently block the pathways for water and waterborne contaminants.
