Flowable fill, a fluid, low strength material, is a cost effective alternative for project owners, specifiers, and contractors to meet a project's backfill or structural fill needs.
A flowable slurry-like material with the consistency of pancake batter, flowable fill is self-leveling, can be placed in one lift with minimal labor and no vibration or tamping, and reaches 95% or more compaction within a few hours of placement, according to Rick Meininger, vice president of research for the National Ready Mixed Concrete Association.
Due to reduced labor, reduced excavation and reduced equipment needs, flowable fill offers lower in-place costs for all your backfill projects.
The editors of Concrete Construction magazine, in their May 1991 issue, included the following 15 reason for owners, specifiers, and contractors to use flowable fill.
1. Readily Available
2. Easy to Deliver
3. Easy to Place
5. Strong and Durable
6. Can be Excavated
7. Requires Less Inspection
8. Allows Fast Return To Traffic
9. Won't Settle
10. Reduces Excavating
11. Improves Worker Safety
12. Allows all-Weather Construction
13. Reduces Equipment Needs
14. Requires No Storage
15. Makes Use of a Waste By-Product
Recommeded Flowable Fill Specification...
This section specifies the requirements for flowable fill used for trenches, support for pipe structures, culverts, utility cuts and other works where cavities exist and where firm support is needed for pavements and structural elements. Flowable fill may also be used to fill abandoned water and sewer lines, abandoned fuel tanks, and where any granular compacted fill is needed as is approved by the Engineer.
Materials shall meet the requirements specified in the following sections of the Standard Specifications:
Portland Cement, Type I, II, or III ASTM C150
Fly Ash* ASTM C618
Fine Aggregate/Mineral Filler **
Air Entraining Admixtures As Per Manufacturer's Specifications
Light Weight Cellular Admixture As Per Manufacturer's Specifications
* LOI limits do not apply.
** Any ASTM or non-ASTM sands or mineral fillers with 100% passing the 1/2" sieve may be considered which produce an acceptable flow and desired performance characteristic.
3. Mix Proportions
The contractor and/or the material supplier shall be responsible for producing a flowable mixture using these guidelines and adjusting the mixture design as called for by the circumstances or as directed by the Engineer.
For excavatable mixes, the flowable fill material should be proportioned to produce a 28-day compressive strength of 75-100 psi (not a specification requirement).
Typical mix design proportions for normal weight flowable fill are as follows:
1. Portland Cement 30-70 lbs/yd3
Fly Ash 250-400 lbs/yd3
Fine Aggregate/Mineral Filler 2000-3000 lbs/yd3
Air Content 0-70%
Water 600 lbs/yd3
2. Portland Cement 30-70 lbs/yd3
Mineral Filler 2000-3000 lbs/yd3
Water 800 lbs/yd3
Note: Weights or volumes of each material should be adjusted to approximate one cubic yard of flowable fill. For
The percentage of cement may be increased above these limits only when early strength is required and future removal of the product is not required. The mix proportions shall be adjusted for removability, pumpability, flowability and setting characteristics. Set times are a product of consolidation of the flowable fill due mainly to dehydration. A decrease in soil permeability, an increase in air content or excessive fine material will cause an increase in the setting time of flowable fill.
Testing of flowable fill in the field is not usually necessary. In the event that testing is required, follow the recommendations of ACI 229.
Modified Slump Test
Scoop, measuring tape, flat edge, 3" x 6" cylinder mold open at both ends, and a flat non-absorbent surface.
1. Set mold upright on flat surface.
2. Scoop representative sample of flowable fill.
1.Fill mold with sample without tamping and then strike off the top with flat edge to form a flat surface.
2.Clear any residue from around the bottom of the mold.
6. Measure the spread's diameter to the nearest 1/2". A spread of 7-9 inches is considered flowable.
Use ASTM C231 procedures where applicable. Unit weight method may also be desirable with high air content mixtures.
No testing shall be done for compressive strengths in the field.
5. Production and Placing
Flowable fill shall be produced and delivered using standard concrete construction equipment and practices. Placing flowable fill shall be by chute, pumping, or other method approved by the Engineer.
6. Construction Requirements
The flowable fill shall be discharged directly from the mixer truck into the space to be filled. No compaction or vibration of the material is required. The mix may be placed part depth or full depth as conditions dictate. Care is to be taken to prevent pipe from floating. Formed walls or other bulkheads shall be constructed to withstand hydrostatic pressure exerted by the plastic flowable fill. All necessary means to confine the material within a designated space shall be provided. Curing of the flowable fill is not required.
7. Limitation of Operation
No flowable fill shall be placed on frozen ground. Mixing and placing of the material is acceptable in freezing temperatures. At the time of placement the flowable fill shall have a temperature of at least 40 degrees F. When flowable fill is placed in freezing temperatures, the material should be covered with blankets overnight. When paving over flowable fill in cold weather, any frozen material on the surface can be scraped off and removed prior to paving.
The flowable fill shall be proportioned and placed as specified herein. In general, the strength desired is the maximum hardness that can be excavated at a later date using conventional excavating equipment. Failure to do so will result in non-compliance.
The flowable fill shall be left undisturbed until the material obtains sufficient strength. Sufficient strength for paving is achieved when the flowable fill can support the weight of foot traffic without apparent deformation. Sufficient strength for supporting vehicular traffic is 2.5 tons per square foot as measured by a pocket penetrometer.
This specification is for information purposes only. Actual job specifications should be accepted by a Professional Engineer
Рука "Опера для планшета скачать"пилота не блистала белизной.
Найда "Игры со змеями"тяжело дышала, и мое логрусово зрение показало вокруг ""ее дрожащих рук угрожающий бледно-красный свет.
Никогда прежде "Saints row 1 скачать торрент"через них не ходил.
Наконец Поль склонился над гробом, открыл "Скачать песню групп любэ"задвижки, снял и отставил в сторону крышку.
Он распечатал конверт и прочел.
На "Русская охота игра"мгновение Чиун, Мастер Синанджу, учитель и друг, перестал существовать для него.
Значит, это уже достаточное расстояние.
В конце концов он утомился и "Фильм криминальное чтиво скачать через торрент"ушел на верхний этаж принять таблетки и закрылся там на ночь.