fly ash

Fly ash use improves concrete performance, making it stronger, more durable, and more resistant to chemical attack. Fly ash use also creates significant benefits for our environment.
Fly ash is one of the residues generated in the combustion of coal. Fly ash is generally captured from the chimneys of coal-fired power plants, and is one of two types of ash that jointly are known as coal ash; the other, bottom ash, is removed from the bottom of coal furnaces. Depending upon the source and makeup of the coal being burned, the components of fly ash vary considerably, but all fly ash includes substantial amounts of silicon dioxide (SiO2) and calcium oxide (CaO).
Use of fly ash in concrete started in the United States in the early 1930’s.
In the past, fly ash was generally released into the atmosphere, but pollution control equipment mandated in recent decades now require that it be captured prior to release.
About 43 percent of fly ash produced in the USA is now recycled, often used to supplement Portland cement content of concrete.
Two classes of fly ash are defined by ASTM C618: Class F fly ash and Class C fly ash. The chief difference between these classes is the amount of calcium, silica, alumina, and iron content in the ash. The chemical properties of the fly ash are largely influenced by the chemical content of the coal burned.
Using concrete can facilitate the process of obtaining LEED® Green Building certification. Leadership in Energy and Environmental Design (LEED) is a point rating system devised by the U.S. Green Building Council (USGBC) to evaluate the environmental performance of a building and encourage market transformation towards sustainable design.
According to the Portland Cement Association, there are at least 5 ways Concrete can help build green:
Five Ways Concrete Helps Build Green
1. Concrete creates sustainable sites.
2. Concrete enhances energy performance.
3. Concrete contains recycled materials.
4. Concrete is manufactured locally.
5. Concrete builds durable structures.
USGBC has issued a credit interpretation that allows for an innovation credit if 40% less cement is used than in typical construction, or if 40% of the cement in concrete is replaced with slag cement, fly ash, or both.
SAS Construction uses concrete with fly ash and slag cement for the concrete floors.

Insulated Concrete Form (ICF)

Insulated Concrete Forms (ICF) make it easy to build green. Concrete contributes more LEED points than most other building material because it is more energy efficient, environmentally friendly, and has a 4-Hour fire rating and superior sound resistance.
SAS Construction uses LOGIX products which are both cost effective and quick to build.
LOGIX has the power and backing of five ICF manufacturers who operate molding plants across North America. Our commitment to product quality and continual innovation is backed up by over 50 years of ICF manufacturing experience.
LOGIX is the only fully integrated insulated concrete form (ICF) system that offers choice of panel thickness, core thickness and web type. LOGIX is also the easiest ICF product to install.
LOGIX is the leading ICF in North America. By providing a wall system that is more energy efficient, stronger, more sound resistant and more environmentally sustainable than virtually any other construction method, LOGIX Insulated Concrete Forms make it easy to build green.

Insulating Concrete

Comparative Analysis of Concrete Insulating Configurations
The thermal advantage of insulation applied to the exterior of a concrete wall is a phenomenon known as thermal inertia, more commonly referred to as thermal mass effect. Thermal mass effect is simply the ability of concrete mass to absorb and store heat. When concrete is used as a wall structure in a building this ability to absorb heat and the placement of the insulation has a profound effect on the building’s performance. When insulation is placed on the exterior of the wall the heat generated in the building conducts through the concrete mass first before meeting the resistance of the insulation on the exterior. If the insulation is sufficient to meet the heating demand on the building the concrete mass will warm to close to room temperature while storing millions of BTU’s of heat energy between the building occupants and the outside elements. This stored heat effectively creates a comfortable living environment by stabilizing indoor temperature fluctuations and reducing condensation. When the cooling of a building is of more concern than heating, the concrete mass can remove unwanted heat from the air reducing the need for air conditioning.
When the insulation applied to a concrete wall is divided equally between the interior surface and the exterior, as in the case with typical insulating concrete forms (ICF), the effectiveness of thermal mass in stabilizing the indoor temperature is not as great. While the benefit of thermal mass is still a key element in the energy performance of these systems the inner layer of insulation compromises the ability of the mass to work to full potential. By using the inner foam layer in the forming process the concrete mass is isolated away from the living space. As the heat demand on the ICF building causes the heat energy to transfer through the wall the first layer of insulation sets up the initial resistance. Once the energy has passed through the inner layer of insulation it is absorbed by the mass of the concrete. Since the layer of insulation applied to the outside governs the rate at which the energy passes through the concrete mass the mass in an ICF building is only protected from the elements by ½ of the building’s insulating potential. Temperature stability resulting from heat radiating from the mass into the living space or absorption of unwanted heat cannot happen in an ICF structure.
When the insulating layer is placed only on the interior side of a concrete wall the thermal mass element is the least effective compared to the other methods of insulating a concrete structure. In a warm climate exterior mass has some benefit due to its ability to absorb heat during the day and release this unwanted heat back to the atmosphere at night. The interior insulation would help to reduce the transmission of this daytime heat to the living space. However residual heat that did find its way into the building, for example through windows and opening doors would stay in the air and raise the indoor temperature quickly if not air-conditioned. These buildings would be more effective in cooling if they had no insulation at all. In the case of a colder climate the insulation on the inside actually puts the thermal mass in a negative position. The insulation adjacent to the wall will keep heat inside giving the space a warm feel but, considering that the down swing to the night time low temperature and the upswing to the day time high is between 12 and 16 hours the concrete mass can be subjected to prolonged cold temperatures even if the daytime high is relatively comfortable. What happens to these buildings is the heat loss potential is determined by the differential in temperature between the cold concrete and the desired indoor temperature and not a fluctuating rate between indoor and out door temperature as would be experienced with a wood structure that has no real thermal mass.
Insulating Concrete Slabs, Foundations and Basements
Concrete slabs, foundations and basement systems come into contact with the ground and face moisture-management and heat-loss issues.
Vapor Retarders and Barriers
When pouring a slab or foundation, a membrane is laid on a layer of crushed stone or subsoil prior to the cement pour. Vapor retarders are used to prevent capillary action of moisture up into the slab
Insulation
Insulation helps prevent heat loss through the slab. Slabs without insulation will lose heat through the ground, which results in heat loss from the room above the slab and higher heating costs. With insulation under the slab, heat loss is reduced, the slab heats to room temperature at a faster rate, and it maintains temperature longer. For buildings with radiant heat on slab, insulation makes the radiant-heating system more efficient. Even if a basement is left unfinished, it is still advisable to insulate under the slab, as the basement is thermally connected to the rest of the house and can draw heat away from living space.
Under-slab insulation can come as polystyrene sheets or rigid boards placed over the subsurface. Under-slab insulation is measured in R-value, much like insulation found elsewhere. Insulation can also be applied around the sides of a slab, foundation or basement.