PERLITE CONCRETE |
SCHUNDLER |
PERLITE INSTITUTE CATELOGUE 32-87 WITH MIX DESIGNS INSULATION VALUES ETC. |
CONSTRUCTION GUIDE |
The Schundler Company 10 Central Street Nahant, MA 01908 732-287-2244 |
PERLITE INSULATING CONCRETE
APPLICATION AND DESIGN
CHAPTER I --- GENERAL
1.1 -Scope
This document brings together pertinent information on the design and placement of perlite insulating concrete. The use of this information is for roof deck applicators responsible for the installation and application of perlite insulating concrete.
1.2-Definition
Perlite insulating concrete is a combination of perlite aggregate. portland cement, air-entraining agent. water and/or other additives producing a concrete with an oven dry density of 50 lb/ft3 (800 kg/rn3) or less.
1.3-Usage
Field placed perlite insulating concrete is commonly used for insulating roof decks, fills and other semi-structural insulation applications.
Perlite insulating concrete roof decks may also employ expanded polystyrene insulation board which is embedded in the concrete.
1 .4-Applicable ASTM Standards
CHAPTER II-MATERIALS
2.1 -Perlite Aggregate
Perlite aggregate conforming to ASTM Designation C 332. Group I.
2.2-Cement
Portland cement conforming to ASTM Designation C 150---either Type I, Type II, or Type III.
2.3-Air Entraining Agent or Other Additives
It is recommended that the perlite aggregate manufacturer be consulted for information and data.
2.4-Water
Water should be clean and free of deleterious substances.
2.5-Control Joints
Shall be a highly compressible vapor permeable material which will compress to one half its thickness under a load of 25 lb/in2 or less (172 kPa).
2.6-Embedded Insulation
Shall be expanded polystyrene insulation board with a minimum density of 1 lb/ft 3 (16 kg/m3).
2.T-Reinforcing Mesh
Shall be a galvanized wire mesh with a minimum cross sectional area of .026 in2 (.169cm 2)
2.7a-Reinforcing Fibers for Reroofing
Shall be alkali-resistant glass or polypropylene--- ¼ to ½ inch in length, 15 denier.
CHAPTER III - CONCRETE PROPERTIES
3.1-Compressive Strength
Should be determined in accordance with ASTM Designation C 495.
3.2-Mechanical Fasteners
Perlite insulating concrete has a nail ability capacity suitable for the mechanical attachment of the base ply of built-up roofing 40 lbs (18.2.kg.) minimum nail pull. ES Nail-Tite MK III (Zono-Tite) nails, Simplex Tube Lok nails, E. G. Insuldeck. Loc-nails, or Berryfast Tape/Staple systems are suitable fasteners for this purpose.
3.3-Oven Dry Unit Weight
Oven dry weight is a. measure of the insulation value of the perlite concrete and may be determined in accordance with ASTM Designation C 495.
INFORMATION FOR CONTRACTORS
* 1985 ASHRAE Handbook of Fundamentals
TABLE 3.1b TYPICAL PHYSICAL PROPERTIES OF PERLITE CONCRETE IN METRIC UNITS
CHAPTER IV - DESIGN CONSIDERATIONS
4.1--Control Joints
It is recommended that a least a 1 inch (25 mm) control joint be provided through the thickness of the perlite concrete at the junction of all roof projections and parapet walls *. This should be increased to 1 1/2 inch (37.5mm) for roof areas over 100 feet (30 meters) in length.
This recommendation assumes that suitable consideration has been given to the use of adequate through-building control joints.
*This recommendation does not apply when the roof deck is designed as a diaphragm to resist horizontal forces and glavanized corrugated metal forms units are employed.
CHAPTER V---PROPORTIONING AND MIX DESIGN
5.1--Materials per Cubic Yard: refer to Table 5.1 below:
5.2-Air Entralnlng Agent
The use of the correct amount of air entraining agent is very important in successful perlite concrete construction. The air entraining agent produces countless tiny air bubbles in the concrete which reduces the density, increases the yield and contributes to the insulation factor of the dry concrete.
5.3-Job Mixing
Perlite insulating concrete should be mixed in a mechanical mixer designed expressly for lightweight insulating concrete. The required amount of water as specified or predetermined for the batch is placed in the mixer, followed by the air entraining solution, cement and perlite aggregate. The batch is then mixed until workable (approximately 1-1/2 to 3 minutes). Check wet density for conformance to specification range, discharge and place immediately. Mixing time is governed by the type of equipment used and can be determined by checking the wet density of the perlite concrete at intervals until the specified wet density is reached.
5.4-Yield Calculation
Yield is defined as the ratio between the volume of the wet perlite concrete as discharged from the mixer and the volume of pertite concrete aggregate used in the mix. The mix proportions included in Tables 5.la and 5.1b are based on extensive field and laboratory tests and are established for 100% yield. If the correct quantities of materials and mixing procedure are used, a 100% yield should result. 100% of yield is of importance from the standpoint of economy and physical properties of the dry concrete.
5.4.1-Field Check for Wet Density
The first step necessary in making a field check for yield is to determine the wet density of the perlite insulating concrete. Wet density can be checked beginning with the first batch mixed. Adjustments to the mixing procedure should be made at that time and additional checks made from time to time during pouring.
A simple method for field checking of wet density is as follows:
(A mix with a typical wet density of 40.5 lb/ft 3)
(A mix with typical wet density of 648 kg/m 3)
5.4.1-Field Check for Yield
The wet density and the weight of total ingredients for the mix being used are then substituted in the following formula:
Consider a mix of 1 bag cement (94 pounds) to 6 cubic feet of perlite concrete aggreage.
The wet density as determined in the example above is 40.2 lbs/ft 3.
The weight of total ingredients is as follow:
Consider a mix of 1 bag cement (42.73 kg) to 6 cubic feet of perlite concrete aggreage (0.17 m 3.
The wet density as determined in the example above is 638 kg/m 3.
The weight of total ingredients is as follow:
5.4.3-Loss of Yield
If the yield as checked by the wet density method is LESS than 100%, a "loss of yield" is evident. A loss of yield may be attributed to one or more of the following factors which should be checked:
CHAPTER VI---INSTALLATION
6.1 -Placement
Perlite concrete should be conveyed from the mixer to the place of final deposit by methods which will prevent segregation or loss of material. Equipment for conveying perlite concrete should be designed to insure delivery without separation of materials or serious loss of air content.
Pumping should be in accordance with recommendations of the perlite producer, and the perlite concrete shall meet the specified properties at the point of placement.
Perlite concrete should be deposited and screened in a continuous operation until the placing of a panel or section is completed.
Expanded polystyrene board should be placed in a minimum 1/8 in. (3.1 mm) wet slurry of insulating concrete. It is recommended the board be covered by perlite concrete to finished thickness before the slurry is
set.
6.2-Curing
Normal Conditions: Perlite concrete has an adequate mixing water content so as to have sufficient water for proper curing of the concrete without additional precautions. Under these conditions the concrete should be permitted to air dry.
Extreme Dry Conditions: When perlite concrete is placed during extreme dry weather, additional water may have to be sprinkled on the concrete for a sufficient period of time to allow hydration of the concrete.
Cold Weather Conditions: For winter pouring the use of high early strength (Type HI) portland cement is recommended. All concrete materials, reinforcement, and forms with which the perlite concrete may come in contact should be free of frost. No frozen material or materials containing ice should be used. When it is anticipated outside temperature will be below 40°F (4.4°C) 24 hours after placing of the concrete, the mixing water should be heated to a maximum of 120°F (48.9°C). Perlite insulating concrete should not be placed during freezing weather unless the contractor is experienced in the special techniques required
6.3-Roofing Recommendations Over Perlite
Concrete
The built-up roofing or single-ply membrane should be applied as soon as the perlite insulating concrete can carry construction traffic, and is dry enough to develop adhesion with hot asphalt: or pitch.
Roof application should proceed when the perlite concrete has been cured. a minimum of three days. Provision shall be made for perimeter or edge venting by use of an open metal gravel guard. or facia.
6.3.1-Mechanical Fasteners
Nailing or stapling are preferred methods of attachment for the base sheet, and shall be used on perlite concrete applied over structural concrete.
CHAPTER VII--- RECOMMENDED PRACTICES FOR WORKMANSHIP AND TOLERANCES
7.1-Variation of Plane
Variation in deck thickness should be no greater than + or -
1/4 in. (6.25 mm) on a 10 ft. (3 in) straight edge. This tolerance does not include variations resulting from substrate.
7.2-Variation In Deck Thickness
Variation in deck thickness should be no greater than ±1/4 in. (6.25 mm) from specified thickness established by averaging measurements taken at 3 points on a 10 ft. x 10 ft. (3 m x 3 m) square.
7.3-Rain or Freezing Damage Before Setting of Concrete
It is recommended the deck be allowed to cure for a
minimum of three days. After freezing or heavy rainfall give a thorough brooming if required before roofing.
That portion of the deck which has excessive scaling should be removed to solid concrete, and patched. Patch additives may be used at the applicator's option.
If minor sealing occurs broom surface before roofing.
Perlite concrete exposed to extreme cold after setting will provide adequate strength to receive roofing if not subjected to mechanical damage. Therefore, all traffic should be prohibited.
Damage after placement caused by other trades should not be the responsibility of the applicator.
CHAPTER VIII-- - ALTERNATIVE DESIGN
8.1-Reroofing
Perlite reroof base is the ideal underlayment for use in renovating existing roofs. It is unsurpassed in correcting irregularities in uneven existing roofs of virtually any material. It provides high insulation values as well as the additional benefits of eliminating ponding, slope-to-drain, lightweight and can often eliminate costly tear-offs of old roofing.
Perlite reroof base is a strong, fiber reinforced nailable base which improves the fire resistance of the roof system. It is used to separate an old roof from anew reroof system while providing a smooth monolithic surface for new built-up roofing or single-ply membranes.
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Oven Dry
Density
lb/ft 3
Density
Range
lb/ft3
Conductivity
Range
"k"*
Strength
Range
lb/in2
Compressive
Strength
lbs/in 2
Density
Range
lbs/ft 3
36
36-42
.83-.97
300-500
300
48-56
30.5
30-36
.71-83
200-300
200
42-50
27
24-30
.58-71
125-200
125
38-44
22
18-24
.46-.58
80-125
80
34-40
Oven Dry
Density
kg/m 3
Density
Range
kg/m 3
Conductivity
Range
W/m. K
Strength
Range
kPa
Compressive
Strength
kPa
Density
Range
kg/m3
576
576-672
.12-.14
2068-3447
2068
768-896
488
480-576
.10-.12
1379-2068
1379
672-800
432
384-480
.08-.10
862-1379
862
608-704
352
288-384
.07-.08
552-862
552
544-640
Materials per Cubic Yard Based on 100% Yield Mix Ratio
(Cement/Perlite
Aggregate
by Volume)Oven Dry
Density
(Typical)
in lb/ft3Cement
in lbs.Perlite
in ft3Water
in
Gallons Air
Entraining
AgentWet
Density
Range
in lb/ft31:4 36 635 lbs 28 61 * 50.5 +/- 3.0 1:5 30.5 510 lbs 28 59.5 * 45.5 +/- 3.0 1:6 27 425 lbs 28 54 * 40.5 +/- 3.0 1:8 22 320 lbs 28 54 * 36.5 +/- 3.0
Materials per Cubic Meter Based on 100% Yield Mix Ratio
(Cement/Perlite
Aggregate
by Volume)Oven Dry
Density
(Typical)
in kg/m3Cement
in kgPerlite
in m3Water
in
m3 Air
Entraining
AgentWet
Density
Range
in kg/m31:4 576 376 lbs 1.0 .30 * 808.0 +/- 48.0 1:5 488 301 lbs 1.0 .29 * 728.0 +/- 48.0 1:6 432 252 lbs 1.0 .27 * 648.0 +/- 48.0 1:8 352 188 lbs 1.0 .27 * 584.0 +/- 48.0
Portland cement:1 bag = 94.0 lbs Perlite aggregate: 6 cubic feet @8.0 lbs/cubic foot = 48.0 Weight of water: 12 gallons @ 8.33 lbs/gallon = 99.06 Air entraining agent: 1.5 lbs (for illustration only--can be very different) = 1.5 Total = 243.46 lbs.
Portland cement:1 bag = 42.73 kg Perlite aggregate: .17 m 3@128 kg/m3 = 21.78 kg Weight of water: 45.42 liters = 45.44 Air entraining agent: 708 ml (for illustration only--can be very different) = .68 Total = 110.63 kg lbs.
For more information, please call or contact:
10 Central Street
Nahant, MA 01908
732-287-2244 or www.schundler.com
email: info@schundler.com