MassConcrete-Guide
Reported byACl Committee207
Mass Concrete-Guide
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MassConcrete-Guide
ReportedbyACI Committee207
Christopher C. Ferraro Chair
Katie J. Barojay Secretary
Jonathan L. Poole Tibor J. PatakyKyle Austin Riding Henry B. PrengerErmest A. Rogalla Ernest K. Schrader
John W. Gajda Mario GarzMichael G. Hemandez Melissa O. Harrison Ronald L Kozikowski Jr. James K. Hicks
Oscar R. Antommatei Fares Y. AbdoTerrence E. Arnold Teck L. ChuaTimothy P. Dolen Barry D. Fehl
Nathaniel F. Tarbox Kuntay K. TalayJames Steve Williamson II Michacl A. WhisonastFouad H. Yazbeck
Consulting Members
William F.KeplerDavid E. Kiefer Stephen B. Tatro
Jeffrey C. AllenRandallP. BassAnthony A. Bombich
CONTENTS
This guide contains a history of the development of massconcrete practice and discussion of materials and concretemixtare proportioning. properties construction methods cnd eqaipment. It covers traditionally placed and consoli-dlated mass concrete for massive structures such as dams cnd provides information applicable to mass structuralheavily reinforced concrete cnd for thermally controlledconcrete such as bridge elements and building fondlations. This guide does not cover rofler-pacted concrete.
DEVELOPMENTS p.2 CHAPTER1-INTRODUCTIONANDHISTORICAL1.1-Scope p.2 1.2-History p. 2
CHAPTER2-DEFINITIONS p.6
PROPORTIONING P.7 CHAPTER3-MATERIALSANDMIXTURE
Keywords: cement; cracking; fly ash; heat of hydration; mass concrete;rise; thermal control plan; themal expansion; volume change. amdus seuu snou mwdns uodoad amx
3.1-General p. 73.2-Cements p.8 3.3Supplementary cementitious materials p. 83.4-Chemical admixtures p. 9 3.5-Aggregates p.103.6Water p. 113.7-Selection of proportions p. 11
guidance in planning designing exeuting and inspecting ACI Committee Reports and Guides are intended forconstruction. This document is intended for the use of indi- viduals who are petent to evaluate the significance andlimitations of its content and remendations and who will accept responsibility for the application of the material itcontains. The American Concrete Institute disclaims any and all reponsibility for the stated principles. The Institute shllnot be liable for any loss or damage arising therefrom.
CHAPTER 4-PROPERTIES p.15 4.1-General p. 15
Reference to this document shall not be made in contractthe Architect/Engineer to be a part of the contract documents documents. If items foumd in this document are desired bythey shallerestatdinmadatory lnguage foicporatin by the Architect/Engineer.
4.2-Strength p. 184.3-Temperature p. 194.4--Elastic properties p. 21 4.5-Creep p. 214.6Volume change p. 22 4.7-Permeability p. 224.8Thermal properties p. 234.9-Shear properties p. 23 4.10-Durability p. 23
Significant tensile streses and strains may result from adecline in temperature as heat from hydration is dissipatedat the volume extremities but not at the mass core. Measures should be taken where cracking due to thermal behavior mayadversely affect structural integrity durability or aesthetics.
This guide contains a history of the development of massconcrete practice and a discussion of materials and concretemixture proportioning properties construction methods and equipment.
concrete dam construction where temperature-related Mass concreting practices were developed largely from pnn pp sem including mat foundations pile caps bridge piers super- has also been experienced in other concrete structures structure elements roadway patches and tunnel linings.
CHAPTER5-CONSTRUCTION p.24
5.1-Batching p. 245.2Mixing p.25 5.3-Placing p.255.4Curing p.27 5.5Forms p. 285.6Placement height and time between adjoining place-ments p. 29 5.7Cooling and temperature control p. 295.9Grouting contraction joints in dams p. 31 5.8-Instrumentation p. 30
High pressive strengths are not typically required intraditional mass concrete structures; however there are somecases such as thin arch dams where high-strength concrete may be specified. Massive structures such as gravity dams resist loads primarily by their shape and mass; strength is of secondary importance. Of more importance are durabilityand properties connected with temperature behavior and thetendency for cracking.
CHAPTER6-REFERENCES p.31Authored documents p. 32
The effects of heat generation restraint and volumeelements and structures are discussed in ACI 207.2R. changes on the design and behavior of massive reinforcedCooling and insulating systems for mass concrete areaddressed in ACI 207.4R.
CHAPTER 1-INTRODUCTIONAND HISTORICAL DEVELOPMENTS
1.1-Scope
1.2-History
two classifications or types. The first type is the traditional Mass concrete covered by this guide generally falls intomass concrete of structures such as dams where most oftwined placements. The scond type consists of individual the structure is mass concrete and is constructed of inter-or distinct placements such as high-rise building founda- tions or bridges and is increasingly referred to as ther-mally controlled concrete. Both types of mass concretehave similar principles and basic considerations; however thermally controlled concrete is often constructed withmercial ready mixed concrete. Thus it may be designed to be pumpable and can consist of self-consolidating high-strength or high-performance concrete which typicallymaterials content than traditional mass concrete. Althoughthis guide mainly focuses on guidance for traditional mass concrete much of the information can also be applicable tothermally controlled concrete.
Historically mass concrete considerations evolved out ofthe use of concrete in dams. The first concrete dams wererelatively small and the concrete was mixed by hand. The portland cement usually had to be aged to ply with agravel and proportioning was by the shovelful (Davis 1963). boiling soundness test the aggregate was bank-run sand andTremendous progress has been made since the early 1900s and the art and science of dam building practiced today has reached a highly advanced state. Presently the selectionand proportioning of concrete materials to produce suit- able strength durability and impermeability of the finishedproduct can now be predicted and controlled with accuracy.
Covered herein are the principal steps from those verysmall beginnings to the present. In large dam construction there is now exact and automatic proportioning and mixing of materials. Concrete in 12 yd² (9 m²) buckets can beplaced by conventional methods at the rate of 10 000 ydP/(10°C) as placed even during extremely hot weather. Grand day (7650 m?/day) at a temperature of less than 50°F536 250 yd (410 020 m) followed by the Itaipu Dam on Coulee Dam still holds the record monthly placing rate ofthe Brazil-Paraguay border with 440 550 yd? (336 840 m?)(Iltaipu Binacional 1981).
dams is generally based on durability conomy and themal The design of traditional mass concrete structures such asrequirements. Strength performance is offen a secondary requirement rather than a primary concem and is some-times specified to be achieved at an age of 56 or 90 daysinstead of 28 days.
1.2.1 Before J900Before the beginning of the twentiethcentury much of the portland cement used in the Unitedcoarse by present standards and quite monly they wereunderburned and had a high free lime content. For dams of
The one characteristic that distinguishes mass concretefrom other concrete work is thermal behavior. Because the reaction between water and cement is exothermic bynature the temperature rise within a large concrete mass where the heat is not quickly dissipated can be quite high.
that period bank-run sand and gravel were used without thebenefit of washing to remove objectionable dirt and fines.to-coarse agregate ratio. Mixing was usually done by hand Concrete mixtures varied widely in cement content and fine-and proportioning by shovel wheelbarrow box or cart The effect of the water-cement ratio (w/c) was unknown andgenerally no attempt was made to control the volume ofby visual observation of the newly mixed concrete. mixing water. There was no measure of consistency except
plums (large stones) were partially embedded in a very wet Some of the dams were of cyclopean masonry in whichconcrete. The spaces between plums were then filed withtion joints and without regular lifts. There were however concrete. Some of the early dams were built without contrac-height of lift was regulated and concrete of very dry consis- notable exceptions where concrete was cast in blocks thetency was placed in thin layers and consolidated by rigoroushand tamping.
Generally mixed concrete was transported to the formsby wheelbarrow. Where plums were employed in cyclopean masonry stiff-leg derricks operating inside the work areamoved the wet concrete and plums. The rate of placementGenerally there was no attempt to moist cure the concrete. was at most a few hundred cubic yards (cubic meters) a day.
Crystal Springs Dam pleted in 1890. This dam is An exception to these general practices was the Lowerlocated near San Mateo CA approximately 20miles(30 km) south of San Francisco. According to available information it was the first dam in the United States inwas specified. The concrete for this 154 ft (47 m) high struc- m x o b ssd x ture was cast in a system of interlocking blocks of speci-fied shape and dimensions. An old photograph indicates that hand tampers were employed to consolidate the dry concrete(concrete with a low water content and presumably very low workability). Fresh concrete was covered with planks as aprotection from the sun and the concrete was kept wet untilhardening occurred.
1.2.2 1900 ro 1930After the tum of the century ated. More and higher dams for irrigation power and water construction of all types of concrete dams greatly acceler-supply were built. Concrete placement by means of towersand chutes became mon. In the United States the port- land cement industry became well established and cement was rarely imported from Europe. ASTM specifications for portland cement underwent little change during the first30 years of the century aside from a modest increase in fine-ness requirement determined by sieve analysis. Except for the limits on magnesia and loss on ignition there were nochemical requirements. Character and grading of aggregates were given more attention during this period. Very substan-tial progress was made in the development of methods ofproportioning concrete. The water-cement strength relation- ship was established by Abrams (1918) from investigationsbefore 1918. Nevertheless little attention was paid to the quantity of mixing water. Placing methods using towers andflat-sloped chutes dominated resulting in the use of exces-
sively wet mixtures for at least 12 years after the importanceof the w/c had been established.
admixtures. There were exceptions such as the sand- Generally portland cements were employed withoutcements used by the U.S. Reclamation Service (now the U.S. Bureau of Reclamation [USBR]) in the construction ofthe Elephant Butte Dam in New Mexico and the Arrowrock Dam in Idaho. At the time of its pletion in 1915 the Arrowrock Dam a gravity-arch dam was the highest dam inthe world at 350 ft (107 m). The dam was constructed with lean interior concrete and a richer exterior face concrete.The mixture for interior concrete contained approximately376 Ib/yd? (223 kg/m²) of a blended pulverized granite- cement bination. The cement mixture was produced at-od jo sued qenbo Koeuxoudde Supuuau Kq ans ou land cement and pulverized granite so that no less than 90%passed the No. 200 (75 mm) mesh sieve. The intergroundbination was considerably finer than the cement being produced at that time.
abutments of Big Dalton Dam a multiple-arch dam built by Another exception occurred in the concrete for one of thethe Los Angeles County Flood Control District during thelate 1920s. Pumicite (a pozzolan) from Friant CA was used as a 20% replacement by mass for portland cement.
concrete went out of style. For dams of thick section the In the early part of the rwentieth century cyelopeanmaximum size of aggregate for mass concrete increasedto 10 in. (250 mm). The slump test had e into use as a means of measuring consistency. The testing of 6 x 12 in.(150 x 300 mm) and 8 x 16 in. (200 x 400 mm) job cylinders became mon practice in the United States. Europeancountries generally adopted the 8 x 8 in. (200 x 200 mm)cube for testing the strength at various ages. By the end of the 1920s mixers of 3 yd° (2.3 m²) capacity were monlyused and there were some of 4 yd? (3 m?) capacity. Only Type I cement (portland cement) was available during thisperiod. In areas where freezing-and-thawing conditions weresevere it was mon practice to use a concrete mixture containing 564 Ib/yd? (335 kg/m²) of cement for the entireconcrete mass. The construction practice of using an interior mixture containing 376 Ib/yd? (223 kg/m?) and an exterior-aAp sem (u/8x ) P/qI 9s Suureuoo aunxu aoeoped to make the dam’s face resistant to the severe climate and yet minimize the overall use of cement. In areas of mildclimate one class of concrete that contained amounts of cement as low as 376 Ib/yd? (223 kg/m?) was used in some dams (TVA 1940).
during the years of 1905 to 1911 in Arizona. This dam An exception was the Theodore Roosevelt Dam builtconsists of a rubble masonry structure faced with rough stone blocks laid in portland-cement mortar made with acement manufactured in a plant near the dam site. For thisstructure the average cement content has been calculated 91） xe q 0rior of the mass rough quarried stones were embedded in a 1:2.5 mortar containing approximately 846 Ib/yd° (502 kg/m²) of cement. In each layer the voids between the closelyspaced stones were filled with a concrete containing 564 Ib/
