PRODUCTION

GENERAL PHYSICAL PROPERTIES

Buildex is produced by quarrying shale and introducing it into a rotary kiln, where it is heated in about one hour to 2000 degrees fahrenheit. During the process the shale expands, becoming less dense, and is vitrified (hardened), just as clay is vitrified into pottery. All organic compounds are burned off in the process. The resulting Buildex particles contain numerous microscopic, non-connected air voids, making the product lightweight, strong, and durable. Since it is processed at high temperatures, Buildex is fire resistant and thermally stable.

Buildex aggregate particles leaving the kiln are rounded to cubical in shape, with particle size from 2 inches (50 mm) down to fines. They are then screened into production sizes, and some larger fractions are crushed into finer fractions. The fractions smaller than 1/4 inch contain some of the angular particles from the crushing process.

Most of our production is shipped in bulk, super sack, and 1 cf bags.

RESOURCES DIRECTORY

Structural Lightweight
Concrete Aggregate

Lightweight Concrete
Masonry Aggregate

Typical Physical Properties of Production Sizes

Production Size
Specific Gravity (a)
Density, lb/cu ft (b)
Percent Absorption (c)
5/8" x 3/8" 1.05 35 25
3/8" x 1/4" 1.10 40 20
1/4" x 1/8" 1.15 42 16
1/8" x 0 1.50 47 10

(A) ASTM C 127 / C 128, bulk specific gravity. 
(B) ASTM C 29, loose unit weight (density). 
(C) ASTM C 127 / C 128, 24 hour absorption.

Cumulative Percent Retained

Typical Gradation of Production Sizes

Sieve
5/8" x 3/8"
3/8" x 1/4"
1/4" x 1/8"
1/8" x 0
3/4"
1/2" 19 0
3/8" 79 3 0
No. 4 99 98 20 0
No. 8 99 89 8
No. 16 98 38
No. 30 99 64
No. 50 81
No. 100 88

Typical Physical Properties of ASTM Blends

ASTM Blend
Specific Gravity (a)
Density, lb/cu ft (b)
Percent Absorption (c)
Saturated Density,
lb/cu ft (d)
3/4" x No. 4 1.08 36 23 52
1/2" x No. 4 1.09 37 22 52
3/8" x No. 8 1.14 40 18 52
3/8" x 0 1.20 44 15 53
1/4" x 0 1.25 45 13 53

(a) ASTM C 127 / C 128, bulk specific gravity.
(b) ASTM C 29, loose unit weight (density) @ normal 6% shipping moisture content.
 
(c) ASTM C127 / C 128, 24 hour water absorption at ambient pressure. Please note that the 24 hour absorption figure is not appropriate for use in determining moisture content of Buildex used in pumped concrete. 
(d) Unit Weight (density) when stockpile ambient saturated for 7 to 14 days for concrete pump placement.

Typical Blended Aggregate Gradation Lightweight Aggregates for Structural Concrete
ASTM C 330 - 3/4" x No. 4

Sieve
Percent Retained
Percent Passing
Typical
Gradation
3/4"x No.4
Specification*
Typical
Gradation
3/4"x No.4
Specification*
1" 0 0 100 100
3/4" 0 0-10 100 90-100
1/2" 14 --- 86 ---
3/8" 60 50-90 40 10-50
No. 4 99 85-100 1 0-15
No. 8 99 --- 1 ---

*ASTM C330 "Standard Specification for Lightweight Aggregates for Structural Concrete".

Typical Blended Aggregate Gradation Lightweight Aggregates for Structural Concrete
ASTM C 330 - 1/2" x No. 4

Sieve
Percent Retained
Percent Passing
Typical
Gradation
1/2" x No. 4
Specification*
Typical
Gradation
1/2" x No. 4
Specification*
3/4" 0 0 100 100
1/2" 8 0-10 92 90-100
3/8" 35 20-60 65 40-80
No. 4 98 80-100 2 0-20
No. 8 99 90-100 1 0-10

*ASTM C330 "Standard Specification for Lightweight Aggregates for Structural Concrete"

Typical Blended Aggregate Gradation Lightweight Aggregates for Structural Concrete
ASTM C 330 - 3/8" x No. 8

Sieve
Percent Retained
Percent Passing
Typical
Gradation
3/8" x No. 8
Specification*
Typical
Gradation
3/8" x No. 8
Specification*
1/2" 0 0 100 100
3/8" 3 0-20 97 80-100
No. 4 85 60-95 15 5-40
No. 8 97 80-100 3 0-20
No. 16 99 90-100 1 0-10

*ASTM C330 "Standard Specification for Lightweight Aggregates for Structural Concrete"

Typical Blended Aggregate Gradation Lightweight Aggregates for Structural Concrete
ASTM C 330 - 3/8" x 0

Sieve
Percent Retained
Percent Passing
Typical
Gradation
3/8" x 0
Specification*
Typical
Gradation
3/8" x 0
Specification*
1/2" 0 0 100 100
3/8" 0 0-10 100 90-100
No. 4 12 10-35 88 65-90
No. 8 45 35-65 55 35-65
No. 16 66 --- 34 ---
No. 30 81 --- 19 ---
No. 50 89 75-90 11 10-25
No. 100 93 85-95 7 5-15

*ASTM C330 "Standard Specification for Lightweight Aggregates for Structural Concrete".

Typical Blended Aggregate Gradation Lightweight Aggregates for Structural Concrete
ASTM C 330 - 1/4" x 0

Sieve
Percent Retained
Percent Passing
Typical
Gradation
1/4" x 0
Specification*
Typical
Gradation
1/4" x 0
Specification*
3/8" 0 0 100 100
No. 4 6 0-15 94 85-100
No. 8 32 --- 68 ---
No. 16 56 20-60 44 40-80
No. 30 75 --- 25 ---
No. 50 87 65-90 13 10-35
No. 100 91 75-95 9 5-25

*ASTM C330 "Standard Specification for Lightweight Aggregates for Structural Concrete"

Typical Blended Aggregate Gradation Lightweight Aggregates for Concrete Masonry
ASTM C 331 - 1/4" x 0

Sieve
Typical Cumulative Grading
Typical Individual Grading
Suggested Individual Grading*
3/8" 0 0 0-2
No. 4 6 6 0-10
No. 8 32 26 15-35
No. 16 56 24 15-35
No. 30 75 19 5-20
No. 50 86 12 5-15
No. 100 91 5 5-15
Pan 100 9 8-20

*ASTM C331 "Standard Specification for Lightweight Aggregates for Concrete Masonry Units."

Buildex Haydite®

Buildex Haydite® is a ceramic structural lightweight aggregate that saves material, energy, labor and transportation costs. It can be used for numerous applications, including asphalt preservation treatments, concrete bridge decks, lightweight geotechnical fills and backfills, and high-rise buildings.

An environmentally friendly product that can be recycled and reused in other applications, Haydite® also has several unique characteristics that contribute to Sustainable Development and LEED™ Green Building certification credits.

The process used to make Haydite® produces a high-quality ceramic aggregate that is structurally strong, durable, environmentally inert, low in density, and highly insulative. It is a natural, non-toxic, absorptive aggregate that is dimensionally stable and will not degrade over time.

Lightweight aggregate particles have a low-particle relative density because of their cellular pore system. The cellular structure within the particles is developed by heating certain raw materials to incipient fusion. The end result is a strong, durable, and lightweight aggregate that contains a uniformly distributed system of pores that are relatively crack-free, high-strength vitreous phase.

Weight reduction and product performance are the primary reason Haydite

  • It lowers shipping costs. Because most construction products are shipped, TO BUILD IS TO TRANSPORT.
  • Dead loads are reduced. Dead load reduction becomes very important in roof top gardens and other elevated applications, and sites where unstable soil conditions exist.
  • Because of the extremely high temperature used in the firing production of Haydite®, it offers excellent thermo-structural stability.
  • The large volume of accessible pores in Haydite® provides a vehicle for absorption, storage and then desorption of water or solutions containing admixtures. This includes rainwater in gardens, and as a carrier of solutions containing chemical admixtures, herbicide and fertilizer.
  • The proven resistance to the degrading effects of wetting/drying makes Haydite® a valuable component of wallboard, roof tiles, and artificial stone.

Haydite® pores close to the surface are readily permeable and fill with water within the first few hours to a few days of exposure to moisture. Interior pores, however, fill extremely slowly, with many months of submersion required to approach saturation. Interior pores are essentially non-interconnected, and a small fraction remain unfilled after years of immersion (ACI 213R-03).

The ceramic nature of the aggregate ensures the product is inert and highly resistant to degradation, thereby making concrete stronger, lighter, and more durable. These same properties also render the product environmentally benign in that it can be reused as fill or base material.

In many applications, Haydite® is blended into soils that benefit from the water absorbing characteristics of its porous nature, which provides aeration as well as a nutritional and moisture buffer that help to modify climate and environmental conditions.

Life Cycle Cost

The current use of any building material is predicated on cost, functionality, durability, aesthetics, or a combination of these. The traditional first cost methodology of owners, designers and public officials around the world has contributed to a non-sustainable system. Decisions based on first cost most often ignore life-long maintenance, rehabilitation and operating cost. Life cycle costing is the only way to properly evaluate the sustainability of a project.

The initial cost of Haydite® lightweight aggregate per cubic yard is usually higher than a comparable unit of normal weight aggregate. But when analyzed from a holistic or product -use perspective, the energy savings it provides almost always offset the initial cost and typically produce significant net savings. These savings come from weight reduction that results in a reduction of overall materials being used, and in construction and performance efficiencies.

The up-front cost of components manufactured with Haydite® is more than offset by the cost savings in the following areas: labor, lower dead loads, better fire resistance resulting in reduced concrete thickness, and less reinforcing required in building frames, girders, piers, and footings. For example, when compared to lightweight and normal weight concrete on a bridge with an 8-inch thick deck, where the LWC has a $20 per CY premium, the finished deck cost is generally less than 1% higher.

Embodied Energy

The embodied energy to manufacture rotary kiln structural lightweight aggregate includes mining, manufacturing, and transporting the material to the jobsite, soil blender, or building product manufacturer. The cost of this embodied energy is often paid back in a very short period, because of the improved thermal performance, lower transportation costs, and reduction of labor costs associated with the building elements. For example, the following embodied energy payback using expanded shale, clay and slate in concrete masonry is less than one year.

It is well documented that the total embodied energy to build a building is only one to three percent of the total occupant energy used by that building over its useful life (Construction Technology Laboratories report project number 180028 conducted for Haydite® 2001). Considering that up to 99 percent of the energy used throughout the building life cycle is primarily a function of climate and occupant behavior, it becomes obvious that our biggest energy resource is efficiency.

Environmental Benefits

Sustainable construction design requires a concern for minimal maintenance and energy demands, balanced again the need for efficiency and long-term performance. There are many changes that can be accomplished in the present that will yield positive results for humanity now and in the future. We believe the utilization of Haydite® lightweight aggregate with all its positive benefits is an important element in the sustainability of the building industry.

Energy Savings

Reducing the concrete density increases its thermal resistance. For example, concrete at 90 lb./ft3 has an R value of 0.26/inch while the R value for 135 lb./ft3 concrete is approximately .10/inch. In other words, the 90 lb./ft3 concrete has a 260 percent better insulation factor than the 135 lb./ft3 concrete (Haydite® Information Sheet 3201, 1999).

HISTORY OF STRUCTURAL LIGHTWEIGHT CONCRETE

The history of lightweight concrete can be traced back to the ancient Romans. The first known use was more than 2000 years ago when several lightweight concrete structures were built in the Mediterranean region, but the three most notable structures were built during the early Roman Empire and include the Port of Cosa, the Pantheon Dome, and the Coliseum. Many of these structures are still standing to this day.

Modern day lightweight concrete was first developed in 1908 and patented by Stephen J. Hayde in 1918 as Haydite®. It is manufactured by the rotary kiln process that creates a uniform and high-quality lightweight ceramic aggregate that can be used in many applications.  – such as lightweight concrete masonry units, high-rise buildings, concrete bridge decks, high performance marine platforms, asphalt bituminous surface treatments, lightweight asphalt chip seal, soil conditioner, and lightweight geotechnical fills. But it’s most notable use is in the construction of high-rise buildings.

HISTORY bell[1]

The first major building project employing structural lightweight concrete in the United States was the Southwestern Bell Telephone Company office in Kansas City. Completed in 1929, the building was originally built as a 14-story structure. But by using structural lightweight concrete, the company found that the foundations and underpinning could support an additional 14 floors – bringing the total to 28 floors.

During manufacturing, lightweight concrete is heated to more than 2000°F. This produces inherent thermal stability, lower thermal conductivity, and a lower coefficient of thermal expansion (ACI 216 Standard Method for Determining Fire Resistance of Concrete and Masonry Construction Assemblies). This makes it more fire resistant than ordinary normal weight concrete.

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