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The Relation between workability and viscosity of freshly mixed concrete Yang, Li 1965

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THE RELATION BETWEEN WORKABILITY AND VISCOSITY OP FRESHLY MIXED CONCRETE BY. LI YANG B.Sc. IN -CIVIL ENGINEERING, CHENG-KUNG UNIVERSITY TAIWAN, CHINA. 1956 A THESIS SUBMITTED IN PARTIAL .FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF APPLIED SCIENCE IN THE DEPARTMENT • OF CIVIL ENGINEERING WE ACCEPT THIS THESIS AS CONFORMING TO THE REQUIRED STANDARDS • THE UNIVERSITY OF BRITISH COLUMBIA APRIL, 1965 In p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l m e n t of the requirements f o r an advanced degree at the U n i v e r s i t y of • B r i t i s h Columbia, I agree that the L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r r e f e r e n c e and study* I f u r t h e r agree that per-m i s s i o n f o r extensive copying of t h i s t h e s i s f o r s c h o l a r l y purposes may be granted by the Head of my Department or by h i s r e p r e s e n t a t i v e s . I t i s understood that,copying or p u b l i -c a t i o n of t h i s t h e s i s f o r f i n a n c i a l gain s h a l l not be allowed without my w r i t t e n permission-Department Of V / / £ng, • r , The U n i v e r s i t y of B r i t i s h Columbia., Vancouver 8 5 Canada Date i i ABSTRACT This paper describes how the author studied the "workability" of freshly mixed concrete. Workability i s a very important and necessary property which forms part of the specifications for concrete but i t s meaning is rather vague. Concrete i s usually required to have a certain slump or flow, as determined in a standard manner, with standard apparatus, but the readings obtained are comparative only and have no., absolute value. The question which the author asks and tries to answer i s , can we treat freshly mixed concrete as a fluid and measure i t s . absolute viscosity and i f so how are slump and flow etc. related to it? What does slump and flow really mean in terms of absolute units? An apparatus was developed which does measure a quantity similar to viscosity and values were obtained for nine different mixes. Readings were however obtained at only one velocity so that the non-Newtonian behaviour of the concrete was not investigated. i v ACKNOY/LEDGEMEHT The author wishes to express his appreciation to his supervisor, Professor W. G. HQslop, for his interest, guidance and advice on this experiment. The author also expresses hie gratitude to the staff of the C i v i l Engineering workshop for their assistance throughout the experiment. This project was made possible through the support of the national Research Council of. Canada. This support i s gratefully acknowledged. April 1965• University of British Columbia, Vancouver, B.C. Canada. i i i . TABLE OP CONTENTS CHAPTER PAGE . INTRODUCTION 1 I HOY/ THE PROBLEM WAS APPROACHED 3 II ORIGINAL APPARATUS AND IT'S BEHAVIOUR 6 I I I MODIFICATIONS OF THE APPARATUS AND OP THE SCOPE OF THE INVESTIGATION 8 IV CALIBRATION OF APPARATUS AND SCOPE OF EXPERIMENTAL WORK TO BE UNDERTAKEN 10 V DESCRIPTION OF THE FINAL EJCPERIMENTAL WORK 13 VI CALCULATIONS 15• VII CONCLUSIONS 19 VIII RECOMMENDATIONS FOR FURTHER RESEARCH 21 TABLES 22 FIGURES . 33 REFERENCES ' 61 INTRODUCTION Concrete has to be strong, enough to take the stresses to which i t is subjected and durable enough to withstand the moisture and temperature'changes of its environment. To do this the quality and quantity of a l l materials used in making concrete ha^e to be carefully specified and controlled, along with the mixing process and method of transportation to the forms. These careful specifica-tions however will only produce the desired quality of concrete i f the consistency of the freshly mixed corfrcete is such that i t can be worked into a l l corners of the forms and around reinforcing steel without leaving air or water pockets or segregated sections . This proper placement must also be achieved with a reasonable and economical amount of tamping or vibration. To make good concrete therefore as well as specifying good materials i n the right quantities, a desirable "consistency" or "workability" or "placeability" for the freshly mixed concrete must also be specified. Standard tests have been developed for measuring this property which .throughout this paper will be referred to as workability Some Standard Tests: i) The Slump. Test • i i ) The Kelly Ball Test i i i ) The Plow Table Test iv) Power's Remoulding Test v) The Vebe Test vi) The Compacting Factor Test. A l l of these tests use standardized equipment and procedure, and produce readings which mean the same thing a l l over the world on a l l jobs but the readings obtained have no absolute value. They are relative values only and though readings from the different methods can be compared there is no real way of saying which is the best and over-what range each gives relative readings of acceptable accuracy. If i t were possible to measure some absolute value of workability similar to the viscosity, of a liquid, workability could be defined accurately and .readings from a l l the standard tests could be assessed properly and compared'. This thesis describes the author's attempt to develop an apparatus to give an absolute measure of workability and to use i t on a few samples of concrete. Some absolute values were obtained and compared with slump, flow and remoulding tests. CHAPTER^  I HOW THE PROBLEM,WAS APPROACHED The work required to deform a liquid depends on the viscous shearing stress and the rate of shearing strain. In the classical development of the theory by Newton, a plate-of area A sq.ft. moves parallel to a fixed boundary at a distance h (ft.) from i t . A force of P lbs. gives the plate a fixed velocity V ft/sec. and viscous shearing forces are developed between the layers of liquid lying between the moving plate and the fixed boundary. (See Pig. 1.) . The unit viscous shearing stress t = P/A lbs/sq.ft. is a function of. the V rate of shearing s t r a i n — . For most pure liquids T varies directly y v w i t h a n d we have *c = u — where u. i s a coefficient of viscosity. u is defined as the dynamic or absolute viscosity and can be P Ik Ph calculated from u = —*r- = lbs. sec/sq.ft. This is Newton's classic h theory of viscosity and liquids for which.H- is a constant are known as Newtonian liquids. To study the workability or viscous behaviour of freshly mixed concrete a question that presents i t s e l f i s , can a block of concrete be made to deform in a manner similar to the block of liquid lying between the plate and the boundary and i f so can a property similar to viscosity be calculated from the force and velocity involved? The idea seemed worth investigating and a deformable box was constructed to deform an eighth inch cube of freshly mixed concrete. The important difference between the deformation of the cube of liquid and the cube 4* of concrete i s , as shown in Pig. 1, in how the forces are applied. la the case of the liquid the external force is applied at the top through the plate and is truly horizontal and the internal forces are a l l horizontal viscous shearing forces. In the case of the concrete the force is applied by one end of the box, the distribution of the force is not known and the forces exerted on the concrete have small vertical components. The internal forces are therefore not a l l horizontal viscous shearing forces. Although the force distribution,-applied to the concrete i s not known the work required to cause the deformation is easy to calculate from . (Work) = F V (At) c c c c In Newton's equation for liquids the work done is (Work) = PV(At) and p (Work) The viscosity of a liquid therefore can be calculated from the formula (Work) h * * = V(At) AV and a siiailar quantity for the concrete can be calculated from the formula (Work) h M = c c ° V (At) A V c 'c c c 5. A -P V (At) h c c c c V (At) A V C C c c . ^ P c (=£) c V A V C c c CHAPTER II ORIGINAL APPARATUS AND IT'S BEHAVIOUR Description of the Apparatus. The apparatus developed is shown in its f i n a l form in Pigs. 2 to' 5 . • The bottom and ends of the box are made of ply-wood and the sides are 2" x 1/8" brass strips which were bolted to the ends through vertical slots. These slots permitted the side strips to bear on each other to provide a tight connection and enabled the box to be deformed without any vertical movement of the sides. The drive was from a reversable constant speed motor through a flex to a rotating nut on along threaded drive rod. The drive rod was thus moved back and forth at constant speed. The velocity of the top of the box i t s e l f could be changed by moving the whole drive mechanisia to different vertical- positions and varying the linkage to the box i t s e l f . The f i n a l linkage to the box was a load c e l l which always remained horizontal, and which was connected to a brush recorder. Behaviour of the Apparatus. Once the apparatus was completed the box was operated empty and f u l l to see how i t behaved. Probably 500 readings were taken. Some of the main observations were: (a) Curves on the brush recorder charts were in general a l l of the same shape. 7. (b) The force necessary to deform the box increases v/ith the amount of deformation. (c) The force necessary to deform the box increases with increased velocity. (d) The force necessary to deform the box varies with the position of the box at the start of the motion. (e) The characteristic curve shape was not due to the concrete. Water, clay, mortar, and concrete a l l produce similar curves. (f) Even with concrete in the box a very large percentage of the force required to deform.the box was due to f r i c t i o n in the box i t s e l f . (g) Concrete must not be allowed to leak into any moving surfaces. (h) Scales available on the brush recorder do not give accurate enough readings of forces. (i) Concrete mixed with Kerosene instead of water to prevent setting bleeds too much to remain of constant consistency. (j) Due to the high friction the flex drive was not a strong enough drive mechanism. Some characteristic brush recorder•curves are shown in Pig. 6. 8. CHAPTER III MODIFICATIONS OP THE APPARATUS AND OP THE SCOPE OP THE INVESTIGATION To reduce f r i c t i o n in the box the brass side strips were pinned individually with a small clearance between strips, and tufflon washers were placed on the pinned connections. The box was lined with a plastic bag to bridge the space between the side strips and prevent leakage of the concrete. The inside of the box and a l l moving parts were liberally oiled and greased. The change in the side strip connections produced some vertical movement of the sides and to keep this to a minimum and also to keep the clearance between the brass strips small, i t was decided to use a much smaller displacement of the box than was originally intended. To improve the drive mechanism the flex was replaced by a reducing gear box and a chain drive . The range of velocities of a point 82 i n . above the hinges of the box was then 0 . 0 4 i n . per sec. to 0 . 1 1 i n . per s e c . To improve the accuracy of the force measurements the load' c e l l was replaced by a dial gage reading to 0 . 0 0 0 1 inches installed in a proving ring. It was found that readings could be taken quite easily every 2 seconds, using as a timer a 2 second pendulum and that from these readings satisfactory force-time or force-displacement curves could be plotted. .9-At this stage of development many more experimental readings were taken and i t was realized that time would not permit investigations at more than one velocity. 10 CHAPTER IV CALIBRATION OP APPARATUS AND SCOPE OP EXPERIMENTAL WORK TO BE UNDERTAKEN Since the u l t i m a t e aim was to f i n d the f o r c e s i n v o l v e d i n the deformation of the'concrete the d i a l gage r e a d i n g pounds f o r c e r e l a t i o n s h i p had to be found and the tare of the box a c c u r a t e l y e s t a b l i s h e d . The p r o v i n g r i n g and d i a l gage were c a r e f u l l y c a l i b r a t e d by dead weight l o a d i n g i n both compression and t e n s i o n . The observed v a l u e s are shown i n Tables 1 and 2 and the c a l i b r a t i o n curves i n P i g s . 7 8. The u n i f o r m i t y of the readings and curves i n d i c a t e a s a t i s f a c t o r y degree of accuracy. The e s t a b l i s h i n g of the t a r e - f o r c e , or the f o r c e necessary to deform the box i t s e l f when subjected to the loads and pressures produced by the concre t e , was a much'more d i f f i c u l t problem. A f t e r many t r i a l s i t was decided to use b a l l o o n s f u l l of water. These were w e l l l u b r i c a t e d , packed i n t o the box and f i l l e d w i t h water to a height of 8 i n . To produce pressures on the w a l l s of the box s i m i l a r to t h a t which might be developed by the h y d r o s t a t i c pressure of 8 i n . of c o n c r e t e , the water pressure i n the b a l l o o n s was i n c r e a s e d w i t h a column of water of a p p r o p r i a t e h e i g h t . The t a r e f o r c e s to deform the box were then r e c o r d e d . To d u p l i c a t e the e f f e c t on f r i c t i o n of the weight of a f u l l box of concrete the b a l l o o n s were sealed f u l l , of water t o a height 1 1 . of 8 inches and then loaded w i t h a f l a t weight (not t o u c h i n g the box) to give the same t o t a l l o a d . The t a r e f o r c e s to deform the box wer>3 again measured . I t was not known which method would give the best r e s u l t s but f o r t u n a t e l y the r e s u l t s were very s i m i l a r . T e s t s were made at v a r i o u s s t a r t i n g p o s i t i o n s but the three p o s i t i o n s r e c e i v i n g the most a t t e n t i o n were s t a r t i n g at - l / 2 i n . and - 1/4 in.from and at the center p o s i t i o n . T e s t s were c a r r i e d on f o r 12 seconds, a l l a t the one v e l o c i t y of 0 . 0 4 i n . per s e c . measured 8g i n . above the bottom of the box. Tests were repeated many times and the average d i a l gage readings from both pressure and weight were converted i n t o l b s . of t a r e . The r e s u l t i n g curves f o r the.three d i f f e r e n t s t a r t i n g p o s i t i o n s are shown on P i g . 9 . Many p r e l i m i n a r y readings, were taken w i t h the i d e a of running t e s t s w i t h the box one h a l f f u l l as w e l l as f u l l but by t h i s time about 1000 readings had been taken and only l i m i t e d time remained. I t was decided t h e r e f o r e to l i m i t the present i n v e s t i g a t i o n to a f u l l box o n l y . The scope of the .present i n v e s t i g a t i o n then became the s t u d y i n g and comparing the w o r k a b i l i t y of nine batches of concrete by the f o l l o w i n g methods: (a) The Standard Plow Test (b) The Standard Slump Test (c) Power's Remoulding Apparatus (d) The new shear box apparatus. ' 12. W i t h the new shear box from which i t was hoped t o c a l c u l a t e t he a b s o l u t e v i s c o s i t y , o n l y one v e l o c i t y and a f u l l box v»as to be used; but t e s t s would be run at t h r e e d i f f e r e n t s t a r t i n g p o s i t i o n s . 13. CHAPTER V DESCRIPTION OP THE PINAL EXPERIMENTAL WORK AND THE DATA OBTAINED Concrete Mix Design Nine d i f f e r e n t concrete mixes were designed to give slumps from 0 to 8 i n c h e s . The A.C.I, mix design, method was used and the Water cement r a t i o was kept constant at 0.6. Sieve a n a l y s i s of the f i n e aggregate i s given i n t a b l e s 3, 4, and 5 and P i g s .10a, 10b, and 10c. Type I cement was used and the complete mix designs are g i v e n i n t a b l e 6 . T y p i c a l T e s t Procedure A l l nine t e s t s were c a r r i e d out i n the concrete l a b o r a t o r y a c c o r d i n g to the f o l l o w i n g procedure: a) Mix 1-? cubic f e e t of concrete thoroughly a c c o r d i n g to the q u a n t i t i e s l i s t e d i n Table 6, adding a l i t t l e b i t of sugar to r e t a r d the s e t t i n g t i m e . b) Measure the temperature of the concrete mix. c) Perform the standard slump t e s t three times and o b t a i n the average v a l u e . d) Perform the standard f l o w t e s t and o b t a i n the percentage f l o w . e) Perform Power's remoulding t e s t and o b t a i n the remoulding e f f o r t . f ) P i l l the shear deformation box f u l l of concrete and c a r r y out thr e e t e s t s , t a k i n g d i a l gage readings every 2 seconds f o r 12 seconds and s t a r t i n g at the - 1/2 i n . , -»i/4 i n . and 0 i n . p o s i t i o n s . 14. g) Remove the concrete from the box and once more perform the slump t e s t to see I f I t has changed appreciably* The concrete was c a r e f u l l y remixed each time i t was used and p a r t i c u l a r a t t e n t i o n was paid to redding. The remoulding and f l o w equipment i s shown i n F i g s * 11 to 15* Data A t y p i c a l data sheet showing the d i a l gage readings obtained f o r the three d i f f e r e n t s t a r t i n g p o s i t i o n s i s shown i n t a b l e 7 which a l s o shows reduction of the readings to l b s . f o r c e * A l l readings were obtained at a v e l o c i t y of 0.04 in/sec at a height of 8| inches above the bottom of the box. This corresponds to a v e l o o i t y of 0.0377 in/seo at the surface of the concrete and 0*0494 in/sec at the proving r i n g * The t o t a l deformation f o r c e s f o r each of the three s t a r t i n g p o s i t i o n s have been p l o t t e d and curves drawn f o r each of the nine mixes• These are shown on F i g e • 16 to 24 i n c l u s i v e • For convenience of c a l c u l a t i o n the tare f o r c e curves f o r the three s t a r t i n g p o s i t i o n s have been p l o t t e d on the same sheets* The r e s u l t s of the slump, flow and remoulding t e s t s are given i n f a b l e 8. CHAPTER VI CALCULATIONS Before calculations were started a close look wa.s taken at the results and especially at the characteristic shape of the total deformation force and"the tare force curves. Why the increase in force with displacement and why the difference i n force with the : different starting position? It was soon realized that both of these are explained by the vertical friction forces exerted by the ends and sides of the box on the concrete. When the box is in a negative position and is being displacedtowards the 0.0 in- or dead center position, these forces are upward and decreasing thus reducing the intensity of the internal shearing force. Once the box i s displaced to the positive side of the 0.0 i n . or dead center position, these forces are downward and increasing and are increasing the internal shearing force. Similar conditions must have varied the friction forces between the water f i l l e d balloons used during the calibration of the tare forces of the box: this i s definitely a source of error. To calculate.the net work done to deform the concrete in a given period of time, we need the area between the total and the tare force curves and since both sets of curves are f a i r l y straight and uniform between 4 seconds and 8 seconds, this appeared to be.a good area to investigate. 16 . Prom 4 seconds to 8 seconds starting at the -0.5 i n . covers the displacement from -0.34 i n . to -0.18 i n . Prom 4 seconds to 8 seconds starting at -0.25.in. covers the displacement from -0.09 i n . to +0.07 i n . Prom 4 seconds to 8 seconds starting at 0,0 i n . covers the displacement from +0.16 i n . to +0.3 2 i n . Since these three averaged together are practically symmetrical about the dead center or 0.0 i n . point, i t would appear that averaging the three net areas between ..'r-seconds and 8 seconds., should give good results and compensate for decreased and increased internal forces on either side of dead center. Table 9 shows the average net force from 4 seconds to 8 seconds required to deform the concrete for each of the nine mixes at each o f the three starting positions. The average for the three positions i s also shown. With the exception of the results of the last four mixes the trend of the readings is quite good but the experimental errors are obviously quite large. The accuracy of the results could be improved i f a smooth curve could be drawn through the plotted experimental values, but against what other quantity should they be p l o t t e d ? I t was thought , that of the othejr workability measurements obtained probably the re-moulding effort should give -the closest co-relation»'.-"Power1 s test does measure. the energy to remould the sample but i t doesv-omit the work done by gravity and by the 4 . 3 lb-, rider plate. It was decided therefore to examine and calculate the total work done during the Power's.test 1 7 . and use these values to check the shear box r e s u l t s . R e f e r r i n g to a diagram of the apparatus i n P i g . 2 5 , i t i s seen that work i s done by l i f t i n g and dropping the concrete and the r i d e r p l a t e each r e v o l u t i o n and a l s o by g r a v i t y i n lowe r i n g the centers of g r a v i t y of the concrete and the r i d e r p l a t e . T o t a l work = (w + wj 7 + W (y n - y j c it 4 C X £. + W_ (7 + 8.8 - S) (30.2 + 4.3>| + 30.2(3.16) + 4.5^ + 4.3(8.8) - 4.3S T o t a l work = 9 .70 n +133.3 - 4.3-3 ( i n . l b s . ) where n = number of l/4 i n . drops and S = slump ( i n . ) Table 10 shows the c a l c u l a t i o n s and the t o t a l work done on each mix dur i n g Power's remoulding t e s t . P l o t t i n g P ag a i n s t these C • v a l u e s (Pig.26) on l o g l o g paper good c o - r e l a t i o n s are found f o r a l l but the l a s t two mixes. I t was f e l t t h a t the experimental readings could be improved by a d j u s t i n g them to the s t r a i g h t l i n e on the l o g l o g p l o t . These adjusted values are shown i n t a b l e 11 and were used f o r the f i n a l c a l c u l a t i o n s of the v i s c o s i t y of the concrete which were made as f o l l o w s : V h a _ J I _ p (.0494N 8 *c ~ / c AYc T *0 ^ . 0 3 7 7 ; (64)(.0377) 13. = 4*34 F lbs. sec/sq.in. c • ! • = 625 P lbs. sec/sq.ft. • c Tha calculated values of u for a l l nine mixes are shown in c Table 8 and Table 11. 19. CHAPTER VII CONCLUSIONS - 4.' Values were obtained which probably do approximate the . ab s o l u t e v i s c o s i t y of f r e s h l y mixed c o n c r e t e . The accuracy i s not good but probably would improve with more experience i n h a n d l i n g the a p p a r a t u s . The author a g a i n p o i n t s out that v a l u e s were obtained at only one.speed, depth and displacement (V /h = .0047 r a d s / s e c . over a displacement of .0188 rads) . Nothing therefore, was learned of the Newtonian or non-Newtonian v i s c o u s p r o p e r t i e s of f r e s h l y mixed c o n c r e t e . A v i t a l assumption i s made a l s o i n assuming th a t w i t h s m a l l displacements of the box near the dead c e n t e r p o s i t i o n the i n t e r n a l f o r c e s i n the concrete are mostly h o r i z o n t a l viscous s h e a r i n g f o r c e s . One reason f o r t r y i n g to measure the v i s c o s i t y of f r e s h l y mixed concrete was to o b t a i n an ab s o l u t e value t o assess p r o p e r l y the v a r i o u s w o r k a b i l i t y measuring devices which now e x i s t . Even i f the values obtained i n t h i s r e s e a r c h are not true v a l u e s of absolute v i s c o s i t y they should serve t h i s purpose s a t i s f a c t o r i l y . To t h i s end, slump, flow and remoulding e f f o r t have been p l o t t e d a g a i n s t v i s c o s i t y on o r d i n a r y graph paper i n P i g . 27 and on l o g l o g graph paper i n P i g . 28. The "results c o n f i r m t h i n g s which are alr e a d y known or suspected and perhaps p r o v i d e some new i n f o r m a t i o n . Slump. The slump t e s t appears to be most s e n s i t i v e at a slump of 2 i n . and to be s a t i s f a c t o r y only i n the 1 i n . t o 4 i n . range. 2 0 . Slump below 1 i n . cannot be a c c u r a t e l y measured. The r e l a t i o n s h i p to v i s c o s i t y appears to be •Slump(in) = 54000 u- ~ 1 , 3 6 c Plow. The f l o w t e s t r e s u l t s d i d not r e l a t e to v i s c o s i t y s a t i s f a c t o r i l y . The t e s t appears to be most s e n s i t i v e at about 40$ (2 i n . slump) and s a t i s f a c t o r y i n the 20$ to 60$ range. (2 i n . to 4 i n . slump.) At very sm a l l flows the r e l a t i o n s h i p appears.to be Plow'$ = 54000 ,u wit h a general t r e n d to 7000 p. ~ ° # 6 ' c c Remoulding; E f f o r t . The Power's remoulding t e s t appears to r e l a t e t o v i s c o s i t y q u i t e w e l l . I t appears to have good s e n s i t i v i t y from 130 t o 30 drops, (i i n . to 7 slump.) The r e l a t i o n s h i p appears to be . Remoulding E f f o r t (drops) = 0 .56 a * 0 * 6 5 • c In general i t appears tha t the three standard w o r k a b i l i t y measuring devices considered are s a t i s f a c t o r y only when the deformation i s mostly v e r t i c a - l and that as soon as other components of the f l o w path become l a r g e the t e s t s l o o s e t h e i r s e n s i t i v i t y and u s e f u l n e s s . (The Vebe t e s t i n v o l v i n g a s h o r t e r f l o w path should be b e t t e r s t i l l t han the remoulding t e s t . ) A l l the standard t e s t s s u f f e r from the in a c c u r a c y caused by the way the concrete i s placed i n the cone. 21 CHAPTER V I I I RECOMMENDATIONS FOR FURTHER RESEARCH Although' the v i s c o s i t y measuring apparatus developed has c e r t a i n fundamental weaknesses and i n a c c u r a c i e s .the author has few id e a s f o r improving i t . I t might however be m o d i f i e d t o operate on i t s .side . With the • same apparatus, some worth while p r o j e c t s which come to mind are: a) V i s c o s i t y measurements at d i f f e r e n t V/h r a t i o s to f i n d some of the non-Newtonian v i s c o u s p r o p e r t i e s of f r e s h l y mixed c o n c r e t e . b) The r e l a t i o n s h i p of Vebe t e s t readings and the "compacting f a c t o r " to v i s c o s i t y . c) The e f f e c t of aggregate g r a d i n g and p r o p o r t i o n i n g on w o r k a b i l i t y . CALIBRATION OP PROVING RING (Tension) Weight ( l b s ) DIAL GAGE READING I IT I I I Average E l o n g a t i o n ( i n ) E l o n g a t i o n ( i n ) E l o n g a t i o n ( i n ) E l o n g a t i o n ( i n ) 0 0.0500 . 0.0500 0.0500 0.0500 1.0 o.0477 0 . 0 4 7 5 0 .0476 0.0476 2 . 0 0 . 0 4 5 2 0 . 0 4 5 2 0 . 0 4 5 1 0 . 0 4 5 2 3.0 0.0428 0 .0426 0 .0426 0 . 0 4 2 7 4 .0 0.0403 0 . 0 4 0 2 0 . 0 4 0 2 0 . 0 4 0 2 5.0 0.0379 0.0377 0 .0376 0 .0377 6 .0 0.0355 0.0354 0.0354 0 . 0 3 5 4 .7.0 0.0331 0.0330 0.0330 0.0330 3 .0 0.0306 0.0306 0 . 0 3 0 5 0.0306 9.0 0.0283 0.0282 0.0281 0.0282 10 .0 0.0258 0 . 0 2 5 9 0.0259 0 . 0 2 5 9 11.0 0.0236 0.0235 0 . 0 2 3 4 0.0235 12.0 0.0213 0.0212 0 . 0 2 1 2 0.0212 13.0 0.0189 0.0189 O.0189 0.0189 14 .0 0 .0167 0.0166 o .016;- 0.0166 15.0 0 . 0 1 4 3 0 . 0 1 4 4 0 . 0 1 4 3 0.0143 , - 3 4.8 x 10 -3 7.3 x 10 -3 9.8 x 10 -3 12 .3 x l O -3 14.6 x 10 -3 17.0 x l O -3 19 .4 x 10 -3 21.8 x l O -3 24.1 x l O -3 26.5 x 10 -3 28.8 x l O -3 31.1 x l O -3 33.4 x l O -3 35.7 xlO -3 TABLE 1 CALIBRATION OP PROVING RING (Compression) Weight ( i t s ) DIAL GAGE READING I n I I I Average C o n t r a c t i o n ( i n ) C o n t r a c t i o n ( i n ) C o n t r a c t i o n (in) C o n t r a c t i o n ( i n ) 0 0.0600 0.0600 0.0600 0.0600 2.3 x 10 3 1.0 0.0623 0.0623 . 0.0624 0.0623 4.9 x 1 0 " ° 2.0 0.0648 0.0648 0.0550 0.0649 7.3 x 10 3 3.0 0.0673 0.0673 ' 0.0674 0.0673 9 .9 x 10~ 3 4.0 0.0700 0.0698 0.0699 0.0699 12.3 x 10 5 5.0 0.0722 0.0723 0.0724 0.0723 14.9 x 10~ 3 6.0 0.0749 0.0748 0.0749 0 .0749 17.5 x 10 " 3 7.0 0.0775 0.0775 0 .0775 0.0775 19.9 x 10~ 3 8.0 0.0798 0.0799 0 .0799 0 .0799 22.5 x 10 J 9.0 0.0825 0 .0824 0.0825 0.0825 25.0 x 10 3 10.0 0 .0849 0 .0849 0.0851 0.0850 27.5 x 10 3 11 .0 0.0875 0 .0875 0.0875 0.0875 29.9 x 10 3 12.0 0.0899 0.0898 0.0900 0.0899 32.4 x 10 ' 13.0 0.0924 0.0924 0.0925 0 .0924 35 .1 x 10*"3 14 .0 0.0951 0.0950 0.0952 0.0951 37.6 x 10 3 15.0 0.0976 0.0975 0 .0977 0.0976 TABLE 2 24 SIEVE-ANALYSIS - COARSE SAND Screen No. • Individual . Weight Retained Individual Percentages Retained Cumulative Percentage Retained 4 6 .01 1.20 1.20 8 72.81 1 4 . 5 7 15.77 14 61 .41 12.28 . 28*05 30 125 .81 25.15 53.20 50 . 128.76 25.75 7 8 . 9 5 100 80.42 16 .10 95.05 Pan 24.78 4.95 Total 500 .00 l&v„00 272.22 TABLE 3 25 SIEVE ANALYSIS - MEDIUM SAND S c r e e n No. I n d i v i d u a l Weight R e t a i n e d I n d i v i d u a l P e r c e n t a g e s R e t a i n e d C u m u l a t i v e P e r c e n t a g e R e t a i n e d 4 0 0 0 8 1 . 7 0 0.56 0.56 14 13.58 4.51 5 . 0 7 30 77.30 25 .80 3 0 . 8 7 50 108.10 36 .10 66 . 9 7 100 76.32 25.38 ' 9 2 . 3 5 • Pan 2 3.00 7.65 T o t a l 300.00 100.00 195.82 • 1.958 T A B L E U 26 SIEVE ANALYSIS - FINE SAND Screen No.' Individual Weight Retained Individual Percentages Retained Cumulative Percentage Retained 4 0 0 0 8 0 0 0 14 0 0 • 0 30 2 4 . 8 3 1 2 . 4 3 1 2 . 4 3 50 9 3 . 3 3 46 .62 5 9 . 0 5 100 7 3 . 8 0 36 .92 95 .79 Pan 8 . 0 4 4 . 0 3 Total 2 0 0 . 0 0 1 0 0 . 0 0 1 6 7 . 2 ? 1 .67 TABLE 5 CONCRETE M I X P R O P O R T I O N ( l cubic yard) A . C . I , Mix Design Method W/C i s constant = 0.60 by weight MIX NO . .WATER ( L B S ) CEMENT ( L B S ) C O A R S E A G G R E G A T E ( L B S ) S A N D ( L B S ) T O T A L ( L B S ) 3/4 i n 1/2 i n Gap 3/8 i n P .S. C . S . 1 275 .00 458 .00 425.00 425.00 425.00 425.00 710.00 868.00 4,011.00 2 291.40 486 .00' 425.00 425.00 425.00 425.00 670 .60 819 .40 3,967.40 3 308.00 514.00 425.00 425.00 42 5.00 425.00 648.45 792.55 3,96 3.00 4 317.00 541.00 425.00 425.00 425.00 425.00 627.75 767.25 3,953.00 5 325.00 555 .00 425.00 425.00 425.00 425.00 612 .00 748 .00 3,9/TO .00 6 ' 342.00 584.00 425.00 425.00 425.00 425.00 581.40 712.60 3,920.00 7 359.00 612 .00 425.00 42 5.00 425.00 425.00 551.70 674-30 3,897.00 8 375 .00 625 .00 425.00 425.00 425.00 425.00 526 .00 644.00 3,870.00 9 392 .00 6 54.00 425.00 425.00 425.00 425.00 496.00 614.00 3,846 .00 S p e c i f i c g r a v i t i e s of cement, C .A. e F .A, are 3.15, 2.68 e 2.64 r e s p e c t i v e l y . TABLE 6 28. SAMPLE DATA SHEET S t a r t i n g P o i n t D i a l Gage -3 i n . x 10 Deformation -3 i n . x 10 Force l b s . - 1/2 i n . 6 .4 3.6 1.50 5.3 4.7 1.96 4.4 '5.6 2.34 3.3. 6.7 2.79 2.3 7.7 3.21 1.6.. 8.4 3.50 - l / 4 ' i n . 6.7 3.3 1.38 6.2 3.8 1.58. 5.6 4.4 1.83 4.5 5.5 2.29 3.5 6 .5 2.71 1.9 . 8.1 3.38 0.0 i n . 6 .6 3.4 1.42 •5.0 5.0 2 .08 3.5 6.5 2.71 1.3 8.7 3.6 3 • 9.1 •10.9 4.54 5.5 14.5 6.05 TA3LE 7 TABLE 8 MIX NO WATER CONTENT lbs/cu.yd SLUMP (in.) PLOW /o REMOULDING EFFORT (drops) ABSOLUTE VISCOSITY ii lbs. c sec/sq.ft. 1 . 275 .00 0 16.6 130 5620 2. 291 .40 1 28.7 90 3060 3. 308.00 2 45.8 65 1875 4 . 317.00 3 49.6 55 1405 5. 325.00 4 60.4 46 1075 6 » 342 .00 67.5 42 925 7 . 359 ,00 6-6g 69.1 37 750 8, 375.00 7 - 7 § 92.0 33 638 9* 392.00 8 98.0 25 425 30 TABLE 9 Average ^ c 1 D s ' Mix Kb. o Displacement i n . Mean F c -0.34 to -0.18 -0 . 0 9 to +0.07 +0.16 to +0.32 1 7 . 17 8.60 11 . 1 7 8 .98 2 3.60 6 .20' 6 .03 5.28 3 3-10 2.93 - 3.01 4 1.533 2 .40 2.40 2 .11 5 1.47 3.13 1.80 1.80 6 1.30 1.73 1 . 4 0 1.48 7 1.40 1.233 0.97 1.20 8 1.37 1.73 1.50 1.50 9 1.23 1.503. 1.033 1.26 TABLE 10 Mix No. Slump. in. n 9 . 7 0 n -4-35 Work (in .lbs .) 1 0 130 1260 +133.3 -0 ' 1393 2 1 90 873 - 4 . 3 1002 3 2 65 630 -8.6 755 4 • 3 55 533 -12.9 653 5 4 46 446 -17.2 562 6 5 42 4 0 7 -21 „5 519 ... 7 6 37 359 -25.8 466 8 7 33 320 -30.1 423 9 8 25 242 -34 A 341 3 2 . TABLE 11 Mix No. F c Measured (lbs) P c Adjusted (lbs) u = 625 P c c lbs .sec/sq .ft . 1 •8 .98 9 . 0 5620 2 5.28 4 . 9 3060 3 3 . 0 1 • 3.o 1875 4 2 .11 2.25 1405 5 1.80 1.72 1075 6 1 .48 1 .48 925 7 1 .20 . 1 .20 750 8 1.50- 1 .02 6 38 9 ' 1.26 0 .68 425 A s2.# FIGURE 1. 34 FIGURE 3 FIGURE kh k--11 C=3 -A jojt: £ 3 X -A I+ 9-(Mi . a-j." '7* PIGURB 5 37 Clay PIGURE 6 PROVING RING CALIBRATION - COMPRESSION DIAL GAGE READING FIGURE 8 40 6 A — A — A — X X X a o — o s t a r t i n g £ s t a r t i n g £ s t a r t i n g £ it 0 t - 1/4" t - 1/2" T o t a l D e f o i mation —" <> £ o rc G ^ — " < >^ -— Tare Fori ;e 0 2 4 6 8 10 12 Time (seconds) FIGURE 9 t 41 42 SIEVE ANALYSIS - MEDIUM SAND 40 30-20 r 3 9 r-l - / M.S. = F.M . = 1.96 -/ \ • Pan No.100 No.50 No.30 No.14 Screen Size • FIGURE 10b. No .8 No .4 43 SIEVE ANALYSIS - PINE SAND 50 R o P-. R M >• R 40 30 20 10 PAN -F.S. P.M. = 1 . 6 7 - / -/ 4 I No. 100 No.50 No,30 Screen Size No. 14 No .8 No .4 FIGURE 10c. 44 FIGURE 11 FIGURE 12 45 FIGURE 15b 4 7 . FIGURE 15c 16 14 12 8 6 A A A — X * X — <5 0 0 i s t a r t i n g at 0 MIX NC ). 3 s t a r t i n g E s t a r t i n g a t - 1/4" t - 1/2" 1 / s T o t a l Defo Pore rmation i c ^^^^^ < I i 1 I 1 i • / > r i / ; / < ] / I / i 1 / ' > / ' 1 — i r ' Tare Pore* \ / / // ^ w ¥ J _' 0 2 4 6 8 10 12 Time (seconds) PIG-TIRE 18 51 12 10 8 0} o M o A — A — A — X X X o——o o— starting a starting a starting a t 0 t - i / 4 " b - 1/2" • i; • MIX NO. 4 * r 0 t a l Defon Force aation c < c ^_ > ^ — / sir — • • - —' J * '—•** ;— — Tare F orce 0 4 6 8 Time (seconds) 10 12 FIGURE 19 52 4 6 3 Time (seconds) 10 12 FIGURE 20 A A A— starting starting starting at 0' at - 1/4" at - 1/2" MIX NO. 6 y—y<—><•— Total Defoi mation i : Pore e < ^^^^^ . — ^ — — /<? jS^f— a ^ ^ — ' — 3 > — ///^ Tare Po: :ce 2 4 6 8 10 12 Time (seconds) FIGURE 21 54 8 © 4 2 A—A—A— v / W \ y starting starting starting at 0 at - 1 / 4 " at - 1 / 2 " MIX NO , 7 A A A Total Defoi mation / \ Fore e ^ y r x — _ i — > Tare I?03 •ce 0 2 4 6 8 1 0 1 2 Time (seconds) FIGURE 22 A r r - A A starting starting starting at 0 at «t 1/4" at - 1/2" HIX K O . 8 <> x—*• X Fore e t ^ ^ ^ ^ ' ) • i i i • S - ^ >«•—• ' -/ / • "1 Tare ¥oi *ce Time (seconds) FIGURE 2 3 56 10 8 6 © 4 o u o £4 2 1 A A A y x x— starting starting starting at 0 at - 1/4B at - 1/2" MIX KG* 9 o 0 o Total Sexor raation i i Fore s —•—^-^ J' /? r\ ' ^ s // /y~ yy x y y • ^ ——-i : ; — f /// /// > j Tar© #01 0 2 4 6 8 10 12 Time (aocondd) FIGURE 24 -0 REFERENCES A 'Study of the Flow-table and the Slump T e s t . George A. Smith and Sanford W. Benham J a n . 1931, p .p .420-438 A .C .2 . proceeding v .27 . A Study of Flow and Flow of Concrete. Inge l y s e and W.R. Johnson J a n . 1931,'p.p .439-467 A .C .2 proceeding v.2 7 . Admixtures and -Workability of Concrete. G. M. W i l l i a m s Feb. 1931, p.p.647-653 v.2 7 . Determining C h a r a c t e r i s t i c s of Concrete i n the Mixed Drum. Emory D. Roberts S e p t . 1931, p.p .59-72 v.28 St u d i e s of W o r k a b i l i t y of C o n c r e t e . T.C. Powers Feb. 1932, p.p. 419-448 v.28. F a c t o r s of W o r k a b i l i t y of P o r t l a n d Cement C o n c r e t e . V/. H. H e r s c h e l and E.A. P i s a p i a May - June. 1936 , p.p. 641-658 v.3 2 . The A p p l i c a t i o n of Some of the Newer Concepts t o the Design of Concrete Mix. •W. M. Dunagan June 1940, p.p. 649-684 v.36 . Admixtures f o r C o n c r e t e . A.C. 2 Committee 212 - Nov. 1944, p.p. 73-88 v. 4 1 . E n t r a i n e d A i r - A F a c t o r i n the Design of Concrete M i x e s . W. A. Cordon June 1946, p.p. 605-620 v. 4 2 . E f f e c t of Mixing Sequence on the P r o p e r t i e s of C o n c r e t e . F . L. F i t z p a t r i c k and W. S e r k i n O c t . 1949, p.p. 137-140 v . 4 6 . 

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