Presented at the Sixth Congress of the FederationInternationale de la Precontrainte, Prague, Czechoslovakia,

June 1970

GROUTING TESTS ONLARGE POST-TENSIONINGTENDONS FORSECONDARY NUCLEARCONTAINMENT STRUCTURESTests of sedimentation (bleeding) and expansion of neat cementgrouts were made as part of a program to insure successfulgrouting of large capacity, long vertical post-tensioning tendons andlarge capacity tendons on sharp curvatures. Water reducing andexpansion producing admixtures for grout are recommended,together with standpipes at all high points of the tendon,to assure elimination of voids.

Morris SchupackSchupack AssociatesStamford, Connecticut

The typical secondary contain-ment structure for a pressurizedwater reactor nuclear power plantof approximately 1000 Mwe capacityis illustrated in Fig. 1. In the UnitedStates the trend has been to prestressthe containment structures if the ac-cident pressure is over 45 psi (3 kg/cm2), generally using unbonded ten-dons. Because of the potential main-tenance problems in using unbondedtendons, which are accessible formonitoring, it has been the desire ofsome power companies to usebonded tendons to avoid what maybe considerable maintenance prob-lems in the future.

GROUTING PROBLEMS WITHLARGE TENDONS

Actual experience of groutinglarge capacity, long vertical tendonsand large capacity tendons on sharp

March-April 1971

curvature with a large included an-gle, is somewhat limited. Experienceto date has not revealed any particu-lar problems, although in verticaltendons, two-stage grouting hasbeen used in several known in-stances. To obtain confidence thatlarge capacity tendons, with ap-preciable curvature and of lengthsin excess of 200 ft. (60 m), could begrouted effectively to give a corro-sion-free protection, considerablegrout testing has been undertakenfor several containment structures.

Assuming that good mixing andpumping equipment is used, thereare basically only two concerns ininsuring proper filling of a conduitwith grout:

1. Sedimentation, sometimescalled bleeding, has manifested it-self in many ways in previous

85

Fig. 1. Typical containment structure

grouting experience. In sectionstaken through moderate size hori-zontal tendons (see Fig. 2) a smallvoid can be seen at the top of thecross-section. This void has gen-erally been reported as an air bub-ble. However, by inspecting theformation of this void in the plas-tic tubes, it could be seen that thisvoid is not an air void but is ac-tually created by the water left ontop of a suspension when the finematerial has settled to the bottom.Some standards permit up to 4 percent bleeding. For a 200 ft. (60 m)long vertical tendon, this wouldresult in a substantial void. Thisamount of bleeding is realistic, butthe specifications generally do notrecommend methods of eliminat-

ing voids caused by sedimenta-tion. It is the author's opinion thatvoids on top of a horizontal con-duit are not consequential, where-as voids formed in tendons withany substantial vertical rise couldbe critical depending on the en-vironment. Therefore, for longvertical tendons, the sedimenta-tion characteristic of the grout hasto be known and if sedimentationcannot be controlled, the spaceleft by the top water lens must beeliminated.

2. On sharp curvature, whereindividual wires or strands aretightly bunched together, thequestion is raised whether it ispossible to get grout through thegrouped elements, particularly on

86ҟ PCI Journal

a radius of, say, 20-ft. (6 Tn).The testing to be described coversprimarily these two items. All thetests performed in these programswere done with a neat cement groutwhich is the grout most commonlyused in the United States. Since ef-fective methods of grouting tendonswere achieved with a neat cementgrout, and a maximum alkali en-vironment was desired for best cor-rosion protection, additional effortwas not made to determine if inertfillers or flyash would have been be-neficial. In this area, further work isdefinitely required.

TESTING FOR SEDIMENTATIONAND EXPANSION

Some of the literature reports thatbleeding phenomenon or sedimenta-tion is practically negligible. Thesetests are generally based on use ofvery short cylinders with ratherlarge diameters which are left openat the top and thus free to permitevaporation. We have found that toappreciate the amount of sedimen-tation that occurs, a 1-liter graduateis a convenient device, but for fieldwork a transparent plastic tubeabout 2 to 4 in. (5 to 10 cm) in di-ameter and about 60 in. (1.5 m) highgives a more representative readingof the sedimentation. For conve-nience we place the grout to the 50-in. (1.3 m) mark in the pipe, usingthe flow cone as a funnel, so we canread the percentage of the expansionand sedimentation directly. In themetric system it is probably moreconvenient to use a 1.00 m (40 in.)column of grout, in which case read-ings in centimeters are directly inpercent. This is suggested as a possi-ble standard for evaluating expan-sion and sedimentation. It is impor-tant that the top of the cylinder besealed to minimize evaporation. Itis also important to remember that

in the first 8 to 10 hr. after mixing,the free water at the top has to beobserved because it has been foundthat re-absorption of the water oc-curs, and the bleeding phenomenonis obscured.

To evaluate the importance of dif-ferent types of cements, admixtures,mixers, efflux time and water-cementratio on expansion and sedimenta-tion, information was gathered fromvarious tests (Table 1). Though thisis not an extensive tabulation, itgives a good picture of what can beexpected. Note that bleeding rangesfrom 0.5 percent to 1.1 percent, andthe expansion from 6 percent to 36percent. From more extensive tabu-lations of grout characteristics it wasconcluded that sedimentation wasnot significantly affected by theabove parameters. Speed of pump-ing and type of pump likewise hadno significant effect.

It seems to be generally acceptedthat locking off the tendon underpressure (up to 100 psi) (7 kg/cm2)is good practice. To check this, tests

Fig. 2. 28-strand horizontal tendonwith sedimentation void at top

March-April 1971ҟ 87

Table 1. Typical neat cement grout characteristics

Type of W/C ratio Mixer type Efflux Maximum Maximumcement (gal/sack) and speed Admixture time, expansion, sedimentation,

sec. percent percentII 0.40 (4.5) 2-5 in. (12.7cm) 0, Intracrete 12 9 0.7

3 blade pro-0.41 (4.6) yellers 1725 RPM Intrusion Aid 11 7 0.5

2800to 0.39 (4.4) 2-5 in. (12.7cm) 0, Intraplast C 15 13 0.6

3600 2 blade pro-Fineness* ellers 1400 RPM

0.42 (4.7) Intracrete 13 6 0.90.37 (4.2) Intraplast RD-4 15 18 0.6

(w/.014%AI) tҟ.0.40 (4.5) Intraplast RD-4 14 17 1.1

(w/.021% Al)t0.40 (4.5) 1-4 blade propeller Intraplast RD-4 17 36 0.7

290 RPM (w/.032% Al),III 0.47 (5.3) Intraplast RD-4 14 14 0.6

(w/.014%AI)t3600 0.53 (6.0) Intraplast RD-4 14 13 0.7

to (w/.021% Al)t4500 0.47 (5.3) Intraplast RD-4 17 33 0.7

Fineness* (w/.032% Al)t

* By Blaine air permeability test1 By weight of cement

were made to determine the amountof sedimentation that occurs underpressure locked in and pressure fromexpansive admixtures. To make atest of this nature, the best visual ob-servations could be made by usinga clear plastic tube so that the ac-tual sedimentation could be seentaking place over a period of time.These tubes were grouted by placingthe grout in from the top to a spe-cific height, and then the tops weresealed so they could support pres-sure. The grout then was pumpeduntil a pressure of 50 to 100 psi (3.5to 7.0 kg/cm2) was obtained. Pres-sure gauges were installed in thegrout pipes. Several interesting itemsappeared from this test. One wasthat expansion caused by the alumi-num powder will appreciably in-crease the pressure within the con-duit. Because of the limitation ofpressure that could be taken by theplastic tubing, additional pressurecaused by the expansion admixtureof only up to 50 psi (3.5 kg/cm2)was permitted on the conduit, andthen the pressure was released. Ofparticular interest, it was noted thatsettlement occurred under pressureand left a void at the top of some ofthe cylinders. Also, intermediate sed-imentation occurred. The materialabove apparently arched, andwater lenses occurred through thecross-section of the conduit (Fig. 3).Seven tests in the 10-ft. (3 m) plastictubes were made using different ad-mixtures and no admixtures. Five ofthe seven tests had water at the topand at some intermediate locations.

To determine the reproducibilityof the sedimentation to larger scale,eleven 5-in. (12.7 cm) diameter spiralsteel tubes, 20 ft. (6 m) high weretested. Both Type II and Type IIIcements were used and bundles of50 1k-in. (12.7 mm) diameter strandswere included in eight of the con-

Fig. 3. Close-up of an intermediatewater lens in a plastic conduit

duits. The results of these tests areshown in Table 2. This test, whichwas developed by Burns and Roe onbehalf of Jersey Central Power andLight Company, uncovered a phe-nomenon not apparently realized be-fore, namely, that the strands causedincreased sedimentation. The phe-nomenon, labeled "water transportmechanism", is believed to be a fil-tering process. The seven-wirestrands consisted of six wireswrapped spirally and tightly arounda slightly larger diameter centerwire. The space between the six wiresis large enough to permit passage ofwater, but not of most of the cementparticle sizes. The space formed be-tween the six spiral wires and thecenter wire becomes a path for thefiltered water. Since the specific grav-ity of the grout is about twice that ofthe water, the water is forced upahead of the grout. This can causewater pockets on top of the tendon inthe range of 20 percent of the total

March-April 1971ҟ 89

Table 2. Grout tests on 20-ft. (6m) high ducts

Initial 50 lh-in. Gross Net voidTube Cement Expansion strand (12.7mm) expansion Sedimentation at top

No. type conditions strands percent percent percent1 II Confined Wet None Confined2 II Confined Wet Yes Confined 12 123 II Confined Wet Yes Confined 12 124 II Free Wet None 8 0.4 05 II Free Wet Yes 4 20 166 II Free Wet Yes 4 20 167 III Free Wet None 8 0.5 08 III Free Wet Yes 6 20 149 III Free Wet Yes 4 10 6

10 II Free Dry Yes 5 17 1211 II Free Dry Yes 5 14 9

Top plate broke under pressure and sedimentation water escapedDucts: 5 in. (12.7cm) o spiral wound 20 ft. (6m) highҟEfflux time: 16 secondsMixer: Eclipse air powered, 3 blade propellersҟAdmixture: Intraplast RD-4

5- 1 in. (14.0cm) o, 2200 RPMW/c ratio—for Type II cement: 4.9 gal./sack (0.43)ҟInitial grout temperature: 69 F

for Type III cement: 6.3 gal./sack (0.56)

C,C,

0

F-

104

103

102

101

100

99

96

97

96

950ҟ2hr 4hr 6hr Shr 0ҟ2hr 4hrҟ6hr

NEATҟGROUTҟ3-51 4 BARS

8hrҟ0ҟ2hrҟ4hrҟ6hrҟ86,

7-^!4 0 STRAND

104

103

102

101

100

99

98

91

96

free volume in the conduit. Fig. 4shows the magnitude of the void cre-ated by the water transport mechan-ism.

Tests were made to determine ifthis water transport mechanism oc-curred with all types of strands, andalso with grouped parallel bars. Itwas thought that possibly a Dyformstrand, which is pulled through a dieafter stranding, would be too tightlypacked for this phenomenon to oc-cur; however, tests indicated aboutthe same phenomenon with Dyformstrand. A loosely twisted strand pro-duced no water transport mech-anism; apparently the spaces be-tween the wires were too great toact as a filter. It is not known if thisloosely woven strand would remainthis way if it were stressed. A tubewith three 5/s-in. (16 mm) bars mani-fested twice the sedimentation of atube with the same grout but nobars. The sedimentation and expan-sion vs. time are shown in Fig. 5.

The effects of different admixtureson the water transport mechanismwere tested. It was thought that pos-sibly a gelling agent, which wouldtend to keep the cement in suspen-sion and form a thixotropic mix,might be useful. This produced no

Fig. 4. Sectioned conduit showingvoid caused by water transport mech-

anism at top of tendon

improvement with strands when us-ing up to 0.05 percent gelling agentby weight of cement. However, smallquantities of gelling agent appearedpromising for wire and bar tendons.It was concluded that the watertransport mechanism was a particularphenomenon of strand tendons andother procedures would have to bedeveloped to cope with this condi-tion. Actually the phenomenonseemed to be beneficial to the grout

Fig. 5. Comparison of expansion and sedimentationMarch-April 1971ҟ 91

72 1vuva0

in that it reduced its water/cementratio and eliminated intermediatelenses.

Other tests were performed byBurns and Roe actually using thestrand to remove the water from thetop end of the tendon. Small scaletests showed promise, but largerscale tests did not produce the de-sired results. Possibly further workwill be fruitful in utilizing this phe-nomenon.

GROUTING 150-FT. VERTICAL TENDONS

For the Robinson Nuclear PowerPlant of Carolina Light and PowerCompany, six 1 -1/g in. (35 mm) highstrength bars in 6-in. (15 cm) di-ameter, 150-ft. (46 m) vertical ductshad to be grouted. Ebasco Services,Inc., the engineer-contractor, desiredto grout the tendon in one stage. Itwas recommended that a gellingagent be incorporated into the ad-mixture and with the cooperation ofSika Chemical Company and Stres-steel Corporation, a testing programwas initiated.

It was thought that the voids pro-duced by sedimentation, describedabove, might be a particular prob-lem with grouted long vertical ten-

dons. Although corrosion consultantsdid not believe water lenses wouldpose a corrosion problem, because ofthe enclosure of a gas-tight gal-vanized duct and the highly alkalineenvironment, it was deemed desir-able to try to eliminate the voids.

From small scale tests, it was con-cluded that, to insure substantial fill-ing of large vertical conduit contain-ing bar tendons, it would be advis-able to eliminate or greatly minimizecement particle sedimentation. Fur-ther, since complete elimination ofsedimentation was in doubt, a suresystem of monitoring the sedimenta-tion process was needed. The sim-plest way to do this was to leave anopen vent hole at the top of the an-chorage cap. This fitted in well withthe decision not to lock off the con-duit under pressure immediatelyafter grouting.

Tests had indicated repeatedlythat sedimentation occurred evenwhen the conduits were maintainedunder pressure, either locked in ordue to grout expansion, since bothtop and intermediate water lenseswere observed under these condi-tions. Furthermore, since initially ex-pansion and sedimentation occur

Penn Dixie IILone Star IAtlas Type I

Lehigh ValleyAllentown Type IIIAllentown Type IAtlas Type I Hudson Valley

7

5

a i 1 2 3 3 7 24 hours

Fig. 6. Nitrogen producing expansion agent performance with dif-ferent cements

92ҟ PCI Journal

simultaneously, (although sedimen-tation may continue after expansionstops) it appeared more logical topermit the expanding grout to over-flow at the top of the conduit, carry-ing with it the water separated bysedimentation.

To minimize the sedimentation,particularly the part that would oc-cur after expansion ceased, varioustypes of admixtures and inert fillerswere considered. The materialwhich seemed most promising was agelling agent. Tests were performedwith admixtures which included agelling agent of the soluble cellulosetype along with expansion agents.The grouting admixture "Intracrete2-2," which produces nitrogen gas asan expansion agent, was modified toinclude the gelling agent. Labora-tory tests consistently showed thevirtual elimination of sedimentationand also indicated (Fig. 6) that thenitrogen gas production was not sig-nificantly dependent on the type ofcement as in the case of hydrogengas developed by the alkali reactionon aluminum powder.

For this particular tendon, TypeIII cement under a carefully con-trolled grouting procedure was ad-vantageous because it has faster in-itial set, thus less time for sedimen-tation. Also, more finely groundcement has slightly less tendency to-ward sedimentation. Tests compar-ing Type II and Type III cementsconfirmed this.

Based on the successful laboratorytests, no further approach wasstudied, and field tests were per-formed on 3-in. (7.6 cm) diameterplastic tubes, 11 ft. (3.35 m) high.These tests indicated no sedimenta-tion and about 5 percent expansion.To confirm the apparent success, two30-ft. (9 m) high grout tests weremade, using 6-in. (15 cm) plexiglas

tubes with six 1-% in. (35 mm) barsinstalled. Fig. 7 shows the thixo-tropic grout rising in the plastic tubethrough the anchorage, free of anysurface water. Besides the visual in-spection of the plexiglas tube andthe plexiglas anchorage assemblyduring the grouting procedure, thetest specimens were cut into varioussections to determine the complete-ness of the grout filling. In all casesthe grout completely filled all spacesincluding the interstices in the an-chorage and under the anchor plate.

Vertical tendon mock-up. Since theexperience in grouting a 150-ft. (46m) tendon is so limited, a mock-upwas made of a 150-ft. (46 m) highconduit to test the grouting proce-dure, including the equipment set-up and the performance of the pro-posed grout pump. Additional ad-vantage could be gained from a testof this nature by determining theactual sedimentation characteristicsof the proposed grout. To performthis test, a 5-in. (13 cm) diameterduct (equal grout cross-sectionalarea) by 138 ft. (42 m) long was setup vertically along the containmentstructure. Since it was a cool day,40 to 50 F (4.5 to 10 C), a trial batch

Fig. 7. Thixotropic grout rising inconduit

March-April 1971ҟ 93

was prepared with 5-1/4 gal. water persack of cement , (0.47). Efflux timewas between 25 and 40 seconds. Be-cause of the thixotropic nature ofthe grout, the efflux time is particu-larly difficult to evaluate. The groutwas readily pumped with the Moynepump (positive displacement screwtype). When the grout reached the2-in. (5 cm) pipe sleeve at the top ofthe 5-in. (13 cm) pipe, the groutingwas immediately stopped since theconsistency of the grout overflow atthe top was excellent. An invertedL-pipe was attached to the 2-in.(5 cm) sleeve so that the expansioncould be measured. The expansion,crudely measured, amounted toabout 0.5 percent. This was to beexpected because the grouting op-eration took about 1 hr., and duringthat time a good part of the expan-sion took place. When the expan-sion was completed, the inverted L-pipe was removed and the surface ofthe 2-in. (5 cm) sleeve covered toprevent evaporation. Observationuntil final set did not reveal any sur-face water or subsidence of thegrout. The performance of this groutwas excellent.

TENDONS ON SHARP CURVATURE

For tendons with a capacity ofover 1000 kips (454 metric tons),90 1/4-in. (6.35 mm) diameter wires or28 '/2-in. (12.7 mm) diameter strandswould be required. If this large num-ber of individual elements is packedtightly into a conduit on sharp curv-ature, there is a question whetherthe grout can find its way betweenall the wires or strands. The limitedinformation on actual performanceindicated that grout could passthrough a reasonable number ofwires or strands effectively, althoughinformation was not available onperformance on sharp curvatures.

The question was, if the wires orstrands were packed tightly to-gether, whether the space betweenthese layers of wires would permitthe air to be exhausted so that thespace could be filled with grout. Thiswas a greater potential problem withwires than with strands because thetwisted strands always tend to havetransverse space available betweenbunched strands.

To settle some of these questionsfor a Metropolitan Edison Companynuclear plant, Gilbert Associates, thearchitect-engineer, prepared a test todetermine the effectiveness of grout-ing wire tendons. Two 90-wire ten-dons in the form of an S verticalcurve were placed in a beam curvedto a 68-ft. (21 m) horizontal radius.The vertical curves were of 20-ft.(6 m) radius. The tendons werestressed and grouted, and with thissharp curvature there was difficultyin getting all the spaces between thewires filled with grout (Fig. 8). Thewriter then suggested that strandtendons should not have this prob-lem, and a test was performed byVSL Corp. in Bern, Switzerland,with a 28-strand tendon, on a 20-ft.(6 m) radius using the VSL system.The results indicated completecoverage of the strand as shown inFig. 9.

This test led Burns and Roe, thearchitect-engineer on another nu-clear power plant for Jersey CentralPower and Light Company, to es-tablish a test program to determinethe feasibility of grouting large post-tensioning tendons effectively. Theresults of these tests, shown in Table3, indicated clearly that to groutwire tendons effectively, the wirescould not be permitted to bunch to-gether or had to be pre-grouted priorto tensioning. However, strand ten-dons could be grouted satisfactorily

94ҟ PCI Journal

C,

CDCD

Table 3. Grouting of stressed tendons in curvature

Duct Tendon Groutadmixture

Specialfeatures

Presence ofcontinuousDiameter System and

in. Type Type supplier voids

TENDONS IN SHARP CURVATURE: radius-20 ft. (6m); included angle-60°; lengt —±26 ft. (8m)

4 Flexible sheath 38-0.5"0 strand SEEE Stressteel Intracrete None No4 Flexible sheath 38-0.5"o strand SEEE Stressteel Intracrete Tendon pre-greased No4 Schedule 40 pipe 29-0.5"0 strand VSL Intracrete Air separator and No

VPN 269 grout recirculation33/4 Spiral wound sheath 22-0.5"0 strand Ryerson WCS Intracrete None No33/4 Spiral wound sheath 22-0.5"0 strand Ryerson WCS Intrusion aid R None No5 Schedule 40 pipe 24-0.6"0 Dyform Freyssinet Intraplast C Spacers No

strand5 Schedule 40 pipe 24-0.6"0 Dyform Freyssinet Intraplast C None No

strand23/4 Flexible sheath 40-0.25"o wire BBRV Ryerson Intrusion aid R Grout recirculation Yes33/4 Spiral wound sheath 90-0.25"0 wire BBRV Ryerson Intrusion aid R Pre-grouted and No

with retarder grout recirculation33/4 Spiral wound sheath 90-0.25"0 wire BBRV Ryerson Intrusion aid R Spacers Yes33/4 Spiral wound sheath 90-0.25"o wire BBRV Ryerson Intrusion aid R Grout recirculation Yes

LONG CURVED TENDONS:ҟradius--!-65 ft. (20m); included angle-60°; length—±75 ft. (23 m)

4 Flexible sheath 38-0.5"0 strand SEEE Stressteel Intracrete None No33/4 Spiral wound sheath 90-0.25"0 wire BBRV Ryerson Intracrete Grout recirculation Yes

Type II CementW/C ratios between 4.2 and 4.7 gal./sack (0.37 and 0.42)Efflux times between 11 and 21 seconds0.5 in. = 12.7mm; 0.6 in. = 15.3mm; 0.25 in. = 6.4mm

10N'

Fig. 8. 90-wire grouted tendon cross-section cut from test beam with ten-

dons on 20-ft. (6 m) radius

under these conditions.On sharp curvature the wires

bunch together against one side ofthe conduit, leaving at the other sidea substantial portion of the cross-sec-tion open to the free flow of grout.The bunching of the wires impedesthe transverse flow of grout, and therapid advancement of the groutthrough the open space does not per-mit the air trapped between thewires to escape. Slow groutingwould help somewhat, but probablywould not give fully successful re-sults. A supplier of wire tendons hassuggested that three wires be

Fig. 9. Cross-section of 28-strandgrouted tendon on 20-ft. (6 m) radius

stranded together to achieve thesame type of transverse venting ex-isting with seven-wire strands.

On the basis of the tests describedabove, it was decided to use onlystrands in grouted curved tendons.To verify that effective grouting wasreproducible in a full-scale tendon,a mock-up of a containment wallsection, Fig. 10, was built with pro-vision to accomodate a series of testtendons. Tendons with up to 54 %-in.(12.7 mm) diameter strands were in-stalled in this test wall, and success-fully grouted. Samples of the ten-dons indicated excellent groutingexcept that the water transportmechanism described for the verti-cal tendons was also present in thevertical rise of the tendons above thesimulated equipment hatch. At thetop of this vertical rise, bleed waterwas trapped and caused a void. Thispointed out the need to permit over-flow of the separated water by meansof some type of stand-pipe.

GENERAL RECOMMENDATIONS

For grouting tendons with any ap-preciable vertical rise, if voids are tobe eliminated, past practices ofgrouting will not do the job. Forthese conditions, it is recommendedthat:

1. For wire or bar tendons a gell-ing plus an expansion additive beused in the grout. The additiveshould be a water reducer but not aretarder. The tendon should not belocked off under pressure, but freeexpansion should be permittedthrough a vertical extension thatrises above the highest point of thetendon. Grout pumping should becontinued until grout of proper con-sistency overflows at the standpipe.The standpipe should remain openuntil all expansion has taken placeand initial set occurs. For smaller

96ҟ PCI Journal

Fig. 10. Full scale grouting test of tendons on sharp curvature

size tendons, the gelling additivemay not be necessary if all othersteps are taken.

2. For strand-type tendons, it isrecommended that neat cementgrout with a water reducing, but nota retarding, admixture be used. Useof a standpipe at all high points inthe tendon, with sufficient capacity tohold the amount of grout requiredto displace the water separated bysedimentation is advised. It is pref-erable to arrange the standpipe sothat the grout may be puddled underthe anchorage to assure that thewater pocket is displaced by thestandpipe grout. Other methods arebeing considered but the abovemethod presently appears best.

ACKNOWLEDGMENTS

Most of the tests for the strand-type tendons were sponsored byGeneral Public Utilities Corporationof New Jersey for its two subsidi-aries, Jersey Central Power and

Light Company and MetropolitanEdison Company. Gilbert Associatesof Reading, Pennsylvania, plannedthe first wire tendon grouting testand Burns and Roe of Oradell, NewJersey, planned the large tendontests. The author, as consultant toGeneral Public Utilities Corporationoversaw and guided the above workand performed additional small-scale tests.

The facilities and cooperation ofSika Chemical Company and Stres-steel Corporation made these testspossible. Tendons for the large-scalegrout test were contributed by Stres-steel Corporation, Inland RyersonConstruction Products Co., Freyssi-net Company, Inc., and VSL Cor-poration.

Tests made on high-strength barswere planned and supervised byEbasco Services, Inc., and the authorfor Westinghouse Electric Corpora-tion, prime contractors for RobinsonNuclear Power Plant of the CarolinaLight and Power Company.

Discussion of this paper is invited. Please forward your discussion to PCI Headquartersby July 1 to permit publication in the July-August 1971 issue of the PCI JOURNAL.

March-April 1971ҟ 97