Open Collections

UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

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

Your browser doesn't seem to have a PDF viewer, please download the PDF to view this item.

Item Metadata

Download

Media
831-UBC_1965_A7 Y3.pdf [ 6.43MB ]
Metadata
JSON: 831-1.0050615.json
JSON-LD: 831-1.0050615-ld.json
RDF/XML (Pretty): 831-1.0050615-rdf.xml
RDF/JSON: 831-1.0050615-rdf.json
Turtle: 831-1.0050615-turtle.txt
N-Triples: 831-1.0050615-rdf-ntriples.txt
Original Record: 831-1.0050615-source.json
Full Text
831-1.0050615-fulltext.txt
Citation
831-1.0050615.ris

Full Text

THE AND  RELATION BETWEEN  VISCOSITY  OP  WORKABILITY  FRESHLY MIXED  CONCRETE  BY. LI B.Sc.  IN -CIVIL  YANG  ENGINEERING, CHENG-KUNG UNIVERSITY TAIWAN, CHINA. 1956  A  THESIS  SUBMITTED  THE  REQUIREMENTS MASTER  OF  IN  IN  PARTIAL .FULFILMENT OF  FOR  THE  APPLIED  THE  •  DEGREE OF  SCIENCE  DEPARTMENT OF  CIVIL ENGINEERING  WE  ACCEPT  THIS  THESIS  REQUIRED  THE  UNIVERSITY  OF  AS CONFORMING  TO  STANDARDS •  BRITISH  APRIL, 1965  COLUMBIA  THE  In the  r e q u i r e m e n t s f o r an  British  mission  for reference  for extensive  p u r p o s e s may  be  cation  of  written  Department  Of  and  Date  Library  study*  by  for  the  V/ /  Head  of my  •  r  ,  Columbia.,  fulfilment  University  shall  I further  agree for  that  of •  per-  scholarly  Department  shall  of  make i t f r e e l y  or  that,copying or  f i n a n c i a l gain  £ng,  the  this thesis  permission-  The U n i v e r s i t y o f B r i t i s h Vancouver 8 Canada 5  the  I t i s understood  this thesis  w i t h o u t my  that  in partial  degree at  copying of  granted  representatives.  this thesis  advanced  Columbia, I agree  available  his  presenting  not  be  by publi-  allowed  ii  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 f o r concrete but i t s meaning i s rather vague. Concrete i s usually required to have a certain slump or flow, as determined i n 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 t r i e s to answer i s , can we treat freshly mixed concrete as a f l u i d and measure i t s . absolute v i s c o s i t y and i f so how are slump and flow e t c . related to it?  What does slump and flow really mean i n terms of absolute units? An apparatus was developed which does measure a quantity  similar to viscosity and values were obtained f o r nine different mixes.  Readings were however obtained at only one velocity so that  the non-Newtonian behaviour of the concrete was not investigated.  iv  ACKNOY/LEDGEMEHT The author wishes to express his appreciation to his supervisor, Professor W. G. HQslop, f o r 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 f o r t h e i r assistance throughout the experiment. This project was made possible through the support of the national Research Council of. Canada. acknowledged.  A p r i l 1965• University of B r i t i s h Columbia, Vancouver, B.C. Canada.  This support i s gratefully  iii.  TABLE OP CONTENTS CHAPTER  PAGE . INTRODUCTION  1  I  HOY/ THE PROBLEM WAS APPROACHED  3  II  ORIGINAL APPARATUS AND IT'S BEHAVIOUR  6  III  MODIFICATIONS OF THE APPARATUS AND OP THE SCOPE OF THE INVESTIGATION  IV  CALIBRATION OF APPARATUS AND SCOPE OF EXPERIMENTAL WORK TO BE UNDERTAKEN  V  8  10  DESCRIPTION OF THE FINAL EJCPERIMENTAL WORK  13  VI  CALCULATIONS  15•  VII  CONCLUSIONS  19  VIII  RECOMMENDATIONS FOR FURTHER RESEARCH  21  TABLES  22  FIGURES REFERENCES '  .  33 61  INTRODUCTION Concrete has to be strong, enough to take the stresses to which i t i s subjected and durable enough to withstand the moisture and temperature'changes of i t s environment. To do t h i s the quality and quantity of a l l materials used i n 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 w i l l only produce the desired quality of concrete i f the consistency of the freshly mixed corfrcete  i s such that i t can  be worked into a l l corners of the forms and around reinforcing steel without  leaving a i r or water pockets or segregated  sections .  This  proper placement must also be achieved with a reasonable and economical amount of tamping or v i b r a t i o n . To make good concrete therefore as well as specifying good materials i n the right quantities, a desirable "consistency" or "workability" or "placeability" f o r the freshly mixed concrete must also be s p e c i f i e d . Standard tests have been developed f o r measuring this property which .throughout this paper w i l l be referred to as workability Some Standard Tests: i)  The Slump. Test •  ii)  The Kelly B a l l Test  iii)  The Plow Table Test  iv) v) vi)  Power's Remoulding Test The Vebe Test 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 i s no r e a l way of saying which i s 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 l i q u i d , 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 l i q u i d depends on the viscous shearing stress and the rate of shearing s t r a i n .  In the c l a s s i c a l  development of the theory by Newton, a plate-of area A s q . f t . moves p a r a l l e l to a fixed boundary at a distance h ( f t . ) from i t .  A force  of P l b s . gives the plate a fixed velocity V f t / s e c . and viscous shearing forces are developed between the layers of l i q u i d lying between the moving plate and the fixed boundary.  (See P i g . 1.) . The  unit viscous shearing stress t = P/A l b s / s q . f t . i s a function of. the V  rate of shearing s t r a i n — .  For most pure liquids T varies directly  v  y  w i t h a n d we have *c = u — where u. i s a coefficient of v i s c o s i t y . u i s defined as the dynamic or absolute viscosity and can be P Ik Ph calculated from u = —*r- = l b s . sec/sq.ft. h  This i s Newton's c l a s s i c  theory of viscosity and liquids f o r which.H- i s a constant are known as Newtonian l i q u i d s . 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 i n a manner similar to the block of l i q u i d l y i n g 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. difference between the deformation  The important  of the cube of l i q u i d and the cube  4* of concrete i s , as shown i n P i g . 1, i n how the forces are applied. la the case of the l i q u i d the external force i s applied at the top through the plate and i s truly horizontal and the internal forces are a l l horizontal viscous shearing forces.  In the case of the concrete  the force i s applied by one end of the box, the d i s t r i b u t i o n of the force i s not known and the forces exerted on the concrete have small v e r t i c a l 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 i s easy to calculate from . (Work) c  =  F  c  V (At) c c  In Newton's equation f o r liquids the work done i s (Work) = PV(At) and p  (Work)  The viscosity of a l i q u i d therefore can be calculated from the formula  *  =  (Work) h V(At) AV  *  and a siiailar quantity f o r the concrete can be calculated from the formula M = °  (Work) h c c V (At) A V c 'c c c  5. P  A-  c  c  V (At) C  . ^  V  P  c  (At)  h  c  C  A V c  c  c  (=£) V A V C c c c  CHAPTER II ORIGINAL APPARATUS AND IT'S BEHAVIOUR  Description of the Apparatus. The apparatus developed i s shown i n i t s 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 v e r t i c a l s l o t s .  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 v e r t i c a l movement of the sides.  The  drive was from a reversable constant speed motor through a f l e x 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 i n general a l l of the same shape.  7. (b)  The force necessary to deform the box increases v/ith the amount of  (c)  deformation.  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 i n 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 i n 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 f r i c t i o n the f l e x drive was not a strong enough drive mechanism.  Some characteristic brush recorder•curves are shown i n P i g . 6.  8. CHAPTER I I I MODIFICATIONS OP THE APPARATUS AND OP THE SCOPE OP THE INVESTIGATION  To reduce f r i c t i o n i n the box the brass side strips were pinned individually with a small clearance between s t r i p s , and t u f f l o n washers were placed on the pinned connections.  The box was  lined with a p l a s t i c 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 l i b e r a l l y oiled and greased. The change i n the side s t r i p connections produced some v e r t i c a l 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 o r i g i n a l l y 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 d i a l gage reading to 0 . 0 0 0 1 inches i n s t a l l e d i n a proving r i n g .  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.  .9At 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 v e l o c i t y .  10 CHAPTER I V CALIBRATION OP APPARATUS AND SCOPE OP EXPERIMENTAL WORK TO BE UNDERTAKEN  Since in  t h e u l t i m a t e a i m was t o f i n d  the deformation  force  relationship  the f o r c e s involved  of the'concrete  the d i a l  gage r e a d i n g pounds  had t o be f o u n d  and t h e t a r e o f t h e box a c c u r a t e l y  established. The by  dead w e i g h t  values  8.  satisfactory The  to  l o a d i n g i n both  gage were c a r e f u l l y  compression  The u n i f o r m i t y o f t h e r e a d i n g s degree o f  indicate  of the t a r e - f o r c e , o r the f o r c e  when s u b j e c t e d t o t h e l o a d s and  i t was d e c i d e d  t o use b a l l o o n s f u l l  w e l l l u b r i c a t e d , packed i n t o height  observed  curves i n  and c u r v e s  p r o d u c e d by t h e c o n c r e t e , was a much'more d i f f i c u l t many t r i a l s  The  accuracy.  establishing  d e f o r m t h e box i t s e l f  calibrated  and t e n s i o n .  1 and 2 and t h e c a l i b r a t i o n  a r e shown i n T a b l e s  Pigs. 7 a  p r o v i n g r i n g and d i a l  t h e box and f i l l e d  o f 8 i n . To p r o d u c e p r e s s u r e s  necessary  pressures  problem.  of water.  After  T h e s e were  with water t o a  on t h e w a l l s o f t h e box  to  t h a t w h i c h might be d e v e l o p e d  by t h e h y d r o s t a t i c p r e s s u r e  of  c o n c r e t e , the water p r e s s u r e  i n t h e b a l l o o n s was i n c r e a s e d  a column of water of a p p r o p r i a t e h e i g h t . t h e box were t h e n To box  similar of 8 i n . with  The t a r e f o r c e s t o d e f o r m  recorded.  duplicate the effect  on f r i c t i o n  of the weight  of a  full  o f c o n c r e t e t h e b a l l o o n s were s e a l e d f u l l , o f w a t e r t o a h e i g h t  11. of  8 i n c h e s and  box) box  to  then  g i v e the  loaded  same t o t a l  wer>3 a g a i n measured .  the best  with a f l a t  r e s u l t s but  load.  The  weight  (not t o u c h i n g  the  t a r e f o r c e s t o deform  the  I t was  not  known w h i c h method  fortunately  the  results  were v e r y  would  similar.  T e s t s were made a t v a r i o u s s t a r t i n g p o s i t i o n s b u t three positions receiving and  - 1/4  for  12  8g  i n . f r o m and  seconds,  t h e most a t t e n t i o n  at the  a l l a t the  one  velocity  i n . above t h e b o t t o m o f t h e b o x .  and  the  average d i a l  converted  into  different  starting  were s t a r t i n g  center p o s i t i o n .  l b s . of t a r e .  The  p o s i t i o n s are  of 0 . 0 4  curves  shown on P i g .  Many p r e l i m i n a r y r e a d i n g s , were t a k e n running time It box  t e s t s w i t h t h e box  about  was  1000  had  half  full  been t a k e n  decided t h e r e f o r e to l i m i t  many  and  times  weight  were  f o r the.three  9. w i t h the  i d e a of  only l i m i t e d  the present  on  s e c . measured  as w e l l a s f u l l and  at - l / 2 i n .  but time  by  this  remained.  i n v e s t i g a t i o n to a  full  only. The  s t u d y i n g and by  readings  one  i n . per  both pressure  resulting  the  T e s t s were c a r r i e d  T e s t s were r e p e a t e d  gage r e a d i n g s f r o m  give  s c o p e o f the .present comparing the  i n v e s t i g a t i o n then  w o r k a b i l i t y of n i n e  t h e f o l l o w i n g methods: (a)  The  Standard  Plow T e s t  (b)  The  Standard  Slump  (c)  Power's R e m o u l d i n g  (d)  The  new  s h e a r box  Test Apparatus apparatus. '  batches  became of  the  concrete  12. W i t h t h e new  s h e a r box f r o m w h i c h i t was  hoped t o  t h e 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 used;  calculate  box v»as t o be  b u t t e s t s w o u l d be r u n a t t h r e e d i f f e r e n t s t a r t i n g  positions.  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 from  0 to 8 inches.  Water cement r a t i o fine  The  was  c o n c r e t e mixes were d e s i g n e d  to give  A . C . I , mix  used  kept  d e s i g n , method was  constant  a t 0.6.  i s g i v e n i n t a b l e s 3,  aggregate  Type I cement was  used  and  the  4,  and  c o m p l e t e mix  slumps  and  Sieve analysis  the  of  the  5 and P i g s .10a, 10b, and  10c.  designs are given i n table  6 . Typical Test  Procedure  All  nine tests  were c a r r i e d  out  i n the  concrete laboratory  a c c o r d i n g to the f o l l o w i n g procedure: a)  Mix  1-? c u b i c f e e t  listed  i n T a b l e 6,  setting  of c o n c r e t e t h o r o u g h l y a c c o r d i n g t o t h e adding  a little  b i t of s u g a r  quantities  to retard  the  time.  b)  Measure the temperature  c)  Perform  the  standard  of the  slump t e s t  concrete  mix.  t h r e e times  and  o b t a i n the  average  value. d)  Perform  the standard f l o w t e s t  e)  Perform  Power's r e m o u l d i n g  f)  Pill  the  shear deformation  three t e s t s , taking d i a l s e c o n d s and  test box  and  o b t a i n the percentage  and full  o b t a i n the remoulding o f c o n c r e t e and  gage r e a d i n g s  s t a r t i n g at the  - 1/2  flow. effort.  c a r r y out  e v e r y 2 s e c o n d s f o r 12  i n . , -»i/4  i n . and  0 i n . positions.  14. g)  Remove t h e c o n c r e t e from the box and once more perform the slump t e s t t o see I f I t has changed a p p r e c i a b l y * The c o n c r e t e 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 p a i d t o r e d d i n g .  The  remoulding and f l o w  equipment i s shown i n F i g s * 11 t o 15* Data A t y p i c a l d a t a sheet showing the d i a l gage r e a d i n g s  obtained  f o r the 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 i s shown i n t a b l e 7 which a l s o shows r e d u c t i o n of the r e a d i n g s t o l b s . f o r c e *  A l l r e a d i n g s were  obtained a t a v e l o c i t y of 0.04 i n / s e c a t a h e i g h t o f 8| i n c h e s above the bottom of the box.  T h i s corresponds  t o a v e l o o i t y of 0.0377 i n / s e o  at the s u r f a c e of the c o n c r e t e and 0*0494 i n / s e c a t the p r o v i n g r i n g * The t o t a l deformation f o r c e s f o r each of the t h r e e 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 t o 24 i n c l u s i v e •  F o r convenience  o f c a l c u l a t i o n the t a r e f o r c e curves f o r the t h r e e 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 s h e e t s * The r e s u l t s of the slump, f l o w and remoulding t e s t s a r e g i v e n 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 t o t a l deformation force and"the tare force curves. force with displacement and why different starting position?  Why  the increase i n  the difference i n force with the : It was  soon realized that both of  these are explained by the v e r t i c a l f r i c t i o n forces exerted by the ends and sides of the box on the concrete.  When the box i s i n a  negative position and i s being displacedtowards the 0.0 i n - or dead center position, these forces are upward and decreasing the intensity of the internal shearing f o r c e .  thus reducing  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  f r i c t i o n 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 d e f i n i t e l y a  source of error. To calculate.the net work done to deform the concrete i n a given period of time, we need the area between the t o t a l 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, t h i s appeared to good area to investigate.  be.a  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 i n . 2  Since these three averaged together are p r a c t i c a l l y 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 f o r 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 f o r each of the nine mixes at each o f the three starting positions. also shown.  The average for the three positions i s  With the exception of the results of the last four mixes  the trend of the readings i s 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 r e moulding effort should give -the closest co-relation»'.-"Power s test does 1  measure. the energy to remould the sample but i t doesv-omit the work done by gravity and by the 4 . 3 lb-, rider p l a t e .  It was decided therefore  to examine and calculate the t o t a l work done during the Power's.test  17. and  u s e t h e s e v a l u e s t o check t h e s h e a r box r e s u l t s . Referring  seen that  work i s done by l i f t i n g  r i d e r plate of  t o a diagram of the apparatus i n P i g . 2 5 , i t i s  gravity  each r e v o l u t i o n  c  + wj  it  (7  + W_  Total  and a l s o  by g r a v i t y  i n lowering the centers  o f t h e c o n c r e t e and t h e r i d e r p l a t e . T o t a l work = (w  (30.2  and d r o p p i n g t h e c o n c r e t e and t h e  7 + W  4  C  (y  - y j  X  £.  n  + 8.8 - S)  + 4.3>| + 30.2(3.16) + 4.5^ + 4.3(8.8) - 4.3S  work  = 9.70 n +133.3 - 4.3-3 ( i n . l b s . )  where n = number  o f l / 4 i n . d r o p s and S = slump ( i n . )  T a b l e 10 shows t h e c a l c u l a t i o n s and t h e t o t a l e a c h mix d u r i n g  Power's r e m o u l d i n g t e s t .  Plotting P  work done on  against  these  C •  values but  ( P i g . 2 6 ) on l o g l o g p a p e r good c o - r e l a t i o n s  the l a s t  could  two m i x e s .  I t was f e l t  be i m p r o v e d by a d j u s t i n g  that  a r e found f o r a l l  the experimental  them t o t h e s t r a i g h t  line  readings  on t h e l o g l o g  plot. T h e s e a d j u s t e d v a l u e s a r e shown i n t a b l e for  the f i n a l  11  and were u s e d  c a l c u l a t i o n s o f t h e v i s c o s i t y o f t h e c o n c r e t e w h i c h were  made a s f o l l o w s :  a _ JI *c ~ / c  V  h AY  c  _ p T *  0  (.0494N 8 ^.0377 (64)(.0377) ;  13. = 4*34 F •  c  l b s . sec/sq.in. !  • = 625 P l b s . sec/sq.ft. • c Tha calculated values of u f o r a l l nine mixes are shown i n c Table 8 and Table 11.  19. CHAPTER V I I CONCLUSIONS  - 4.'  Values absolute  were o b t a i n e d  viscosity  good b u t p r o b a b l y the apparatus. at  of f r e s h l y  w h i c h probably do a p p r o x i m a t e t h e . mixed c o n c r e t e .  would i m p r o v e w i t h more e x p e r i e n c e  The a u t h o r  a displacement  i s not  i n handling  a g a i n p o i n t s out t h a t v a l u e s were  o n l y o n e . s p e e d , d e p t h and d i s p l a c e m e n t  over  The accuracy  o f .0188 r a d s ) .  (V / h =  Nothing  .0047  obtained  rads/sec.  therefore, was l e a r n e d o f  t h e N e w t o n i a n o r non-Newtonian v i s c o u s p r o p e r t i e s o f f r e s h l y concrete.  A vital  a s s u m p t i o n i s made a l s o i n a s s u m i n g t h a t  small displacements internal  mixed with  o f t h e box n e a r t h e dead c e n t e r p o s i t i o n t h e  f o r c e s i n the concrete a r e mostly  h o r i z o n t a l viscous  shearing f o r c e s . One r e a s o n  f o r t r y i n g t o measure t h e v i s c o s i t y  of f r e s h l y  m i x e d c o n c r e t e was t o o b t a i n a n a b s o l u t e v a l u e t o a s s e s s p r o p e r l y t h e various values  w o r k a b i l i t y m e a s u r i n g d e v i c e s w h i c h now e x i s t . obtained  viscosity end,  they  i n t h i s r e s e a r c h a r e not t r u e v a l u e s should  serve  this  slump, f l o w and r e m o u l d i n g  viscosity  of absolute  purpose s a t i s f a c t o r i l y . effort  Even i f the  have b e e n p l o t t e d  To t h i s against  on o r d i n a r y g r a p h p a p e r i n P i g . 27 and on l o g l o g g r a p h  paper i n P i g . 28. The suspected  Slump. 2  " r e s u l t s c o n f i r m t h i n g s w h i c h a r e a l r e a d y known o r  and p e r h a p s p r o v i d e  The slump t e s t  some new i n f o r m a t i o n .  a p p e a r s t o be most s e n s i t i v e  i n . and t o be s a t i s f a c t o r y  a t a slump o f  only i n the 1 i n . t o 4 i n . range.  20. Slump  below 1 i n . cannot  viscosity  The f l o w t e s t  The t e s t  measured.  appears  satisfactory  54000 u- ~ c  =  results  t o be most  sensitive  3  quite  a t about  i n .to 7  slump.)  (The Vebe t e s t  the t e s t s  appears t o r e l a t e t o  The r e l a t i o n s h i p  (drops) = 0.56  a * c  appears 0  *  6  f r o m 130 t o t o be  5  the three standard workability  devices considered are s a t i s f a c t o r y  p a t h become l a r g e  o n l y when t h e d e f o r m a t i o n  a s s o o n a s o t h e r components o f t h e f l o w loose t h e i r  sensitivity  and u s e f u l n e s s .  i n v o l v i n g a s h o r t e r f l o w p a t h s h o u l d be b e t t e r  than the remoulding t e s t . )  At very  t o 7000 p. ~ ° c  t o have good s e n s i t i v i t y  In general i t appears that  inaccuracy  i n . t o 4 i n . slump.)  remoulding t e s t  I t appears  m o s t l y v e r t i c a - l and t h a t  satisfactorily.  40$ (2 i n . slump) a n d  with a general trend  well.  . Remoulding E f f o r t •  measuring  6  a p p e a r s . t o be  Remoulding; E f f o r t . The Power's  30 d r o p s , (i  ,  d i d not r e l a t e t o v i s c o s i t y  Plow'$ = 54000 ,u c  viscosity  1  i n t h e 2 0 $ t o 60$ r a n g e . (2  small flows the r e l a t i o n s h i p  is  The r e l a t i o n s h i p t o  a p p e a r s t o be •Slump(in)  Plow.  be a c c u r a t e l y  A l l the standard tests  c a u s e d by t h e way t h e c o n c r e t e i s p l a c e d  still  s u f f e r from the i n the cone.  #  6  '  21 CHAPTER V I I I RECOMMENDATIONS FOR FURTHER RESEARCH  Although' t h e v i s c o s i t y certain  fundamental  measuring  apparatus  d e v e l o p e d has  weaknesses and i n a c c u r a c i e s .the a u t h o r has f e w  ideas f o r improving i t .  I t might  however be m o d i f i e d t o o p e r a t e  on i t s .side . W i t h t h e • same a p p a r a t u s , some w o r t h w h i l e p r o j e c t s  which  come t o mind a r e : a)  Viscosity of  b)  V/h r a t i o s  t h e non-Newtonian v i s c o u s p r o p e r t i e s  The r e l a t i o n s h i p factor"  c)  measurements a t d i f f e r e n t  o f Vebe t e s t  to find  of f r e s h l y  some  mixed c o n c r e t e .  r e a d i n g s and t h e " c o m p a c t i n g  to viscosity.  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 I Weight (lbs)  PROVING  RING  DIAL GAGE READING IT  III  (Tension) Average  Elongation (in)  Elongation (in)  Elongation (in)  0.0500 .  0.0500  0.0500  0.0500  1.0  o.0477  0.0475  0 .0476  0.0476  2.0  0.0452  0.0452  0.0451  0.0452  3.0  0.0428  0.0426  0.0426  0.0427  4 .0  0.0403  0.0402  0.0402  0.0402  5.0  0.0379  0.0377  0.0376  0.0377  6 .0  0.0355  0.0354  0.0354  0.0354  0.0331  0.0330  0.0330  0.0330  3 .0  0.0306  0.0306  0.0305  0.0306  9.0  0.0283  0.0282  0.0281  0.0282  10 .0  0.0258  0.0259  0.0259  0.0259  11.0  0.0236  0.0235  0.0234  0.0235  12.0  0.0213  0.0212  0.0212  0.0212  13.0  0.0189  0.0189  O.0189  0.0189  14 . 0  0 .0167  0.0166  o .016;-  0.0166  15.0  0.0143  0.0144  0.0143  0.0143  0  Elongation (in)  ,-3  .7.0  TABLE 1  4 . 8 x 10 7.3 x 10 9.8 x 10 12 . 3 x l O 14.6 x 10 17.0 x l O 19.4 x 10 21.8 x l O 24.1 x l O 26.5 x 10 28.8 x l O 31.1 x l O 33.4 x l O 35.7 x l O  -3 -3 -3 -3 -3 -3 -3 -3 -3 -3 -3 -3 -3 -3  CALIBRATION OP  I  PROVING  RING  (Compression)  DIAL GAGE READING III n Contraction Contraction (in) (in)  Average Contraction  Weight (its)  Contraction  0  0.0600  0.0600  0.0600  0.0600  1.0  0.0623  0.0623  . 0.0624  0.0623  2.0  0.0648  0.0648  0.0550  0.0649  3.0  0.0673  0.0673  0.0674  0.0673  4.0  0.0700  0.0698  0.0699  0.0699  5.0  0.0722  0.0723  0.0724  0.0723  6.0  0.0749  0.0748  0.0749  0.0749  7.0  0.0775  0.0775  0 .0775  0.0775  8.0  0.0798  0.0799  0.0799  0.0799  9.0  0.0825  0 .0824  0.0825  0.0825  10.0  0 .0849  0 .0849  0.0851  0.0850  11 .0  0.0875  0 .0875  0.0875  0.0875  12.0  0.0899  0.0898  0.0900  0.0899  13.0  0.0924  0.0924  0.0925  0.0924  14 .0  0.0951  0.0950  0.0952  0.0951  15.0  0.0976  0.0975  0.0977  0.0976  (in)  '  TABLE 2  (in)  2.3 x 10  4.9  3  x 10"°  7.3 x 10  3  9 .9 x 1 0 ~ 12.3 x 10  3  5  14.9  x 10~  3  17.5  x 10 "  3  19.9  x 10~  3  22.5  x 10  J  25.0  x 10  3  27.5  x 10  3  29.9  x 10  3  32.4 x 10  '  35 .1 x 10*"  3  37.6  x 10  3  24  SIEVE-ANALYSIS - COARSE SAND  Screen No. • 4  Individual . Weight Retained  Individual Percentages Retained  6 .01  1.20  Cumulative Percentage Retained 1.20  8  72.81  14.57  14  61.41  12.28  . 28*05  30  125 .81  25.15  53.20  50  . 128.76  25.75  78.95  100  80.42  16 .10  95.05  Pan  24.78  4.95  Total  500 .00  l&v„00  TABLE 3  15.77  272.22  25  SIEVE ANALYSIS  S c r e e n No.  - MEDIUM SAND  Individual Weight Retained  Individual Percentages Retained  Cumulative Percentage Retained  4  0  0  0  8  1.70  0.56  0.56  14  13.58  4.51  5.07  30  77.30  25 .80  30.87  50  108.10  36 .10  66.97  100  76.32  25.38  ' 92.35  • Pan  2 3.00  7.65  300.00  100.00  Total  195.82  • TABLE U  1.958  26  SIEVE ANALYSIS  Screen No.'  - F I N E SAND  Individual Weight Retained  Individual Percentages Retained  Cumulative Percentage Retained  4  0  0  0  8  0  0  0  14  0  0  • 0  30  24.83  12.43  12.43  50  93.33  46 . 6 2  59.05  100  73.80  36 .92  95 . 7 9  Pan  8.04  4.03  200.00  100.00  Total  167.2?  1.67  TABLE 5  CONCRETE M I X P R O P O R T I O N ( l c u b i c y a r d ) A . C . I , M i x D e s i g n Method W/C i s c o n s t a n t = 0.60 by w e i g h t .WATER (LBS)  CEMENT (LBS)  1  275 .00  2  MIX NO .  COARSE AGGREGATE ( L B S )  SAND ( L B S ) P .S. C.S.  TOTAL ( L B S )  3/4 i n  1/2 i n  Gap  3/8 i n  458 .00  425.00  425.00  425.00  425.00  710.00  868.00  4,011.00  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/ O .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  Specific  gravities  o f cement, C .A. e F .A, a r e 3.15,  TABLE 6  2.68  e  T  2.64  respectively.  28. SAMPLE DATA SHEET  Starting Point  Dial in.x  - l/4 'in.  10  -3  Deformation in.x  Force lbs .  1.50  5.3  4.7  1.96  4.4  '5.6  2.34  .4  3.3.  6.7  2.79  2.3  7.7  3.21  1.6..  8.4  3.50  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  8.1  3.38  3.4  1.42  5.0  2 .08  3.5  6.5  2.71  1.3  8.7  3.6 3  •10.9  4.54  14.5  6.05  1.9  .  6 .6  •5.0  0.0 i n .  10  -3  3.6  6  - 1/2 i n .  Gage  • 9.1 5.5  TA3LE 7  TABLE 8  SLUMP (in.)  PLOW /o  MIX NO  WATER CONTENT lbs/cu.yd  1.  275 .00  0  16.6  2.  291 . 4 0  1  3.  308.00  4.  REMOULDING EFFORT (drops)  ABSOLUTE VISCOSITY ii l b s . c sec/sq.ft.  130  5620  28.7  90  3060  2  45.8  65  1875  317.00  3  49.6  55  1405  5.  325.00  4  60.4  46  1075  »  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  6  30  TABLE 9  Average ^ ' Mix Kb.  o  1  D  c  s Mean  Displacement i n .  F  c  -0.34 t o -0.18  - 0 . 0 9 t o +0.07  1  7.17  8.60  2  3.60  6 .20'  3  3-10  2.93  4  1.533  2 .40  2.40  2 .11  5  1.47  3.13  1.80  1.80  6  1.30  1.73  1.40  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  +0.16  t o +0.32  11.17  8 .98  6 .03  5.28  -  3.01  TABLE 10  Mix No.  ...  Slump. in.  n  9.70n  -4-35  Work (in .lbs .)  -0  ' 1393  1  0  130  1260  2  1  90  873  -4.3  1002  3  2  65  630  -8.6  755  4  • 3  55  533  -12.9  653  +133.3  5  4  46  446  -17.2  562  6  5  42  407  -21 „5  519  7  6  37  359  -25.8  466  8  7  33  320  -30.1  423  9  8  25  242  -34 A  341  32.  TABLE 11  Mix No.  P  F c Measured (lbs)  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  3.01  • 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  1.26  0 .68  425  9  '  .  A 2.# s  FIGURE 1.  34  FIGURE 3  FIGURE  kh  k-  -11  -A C=3  jojt:  £3  -A  X  I+ 9  (Mi .  a-  j."  '7*  PIGURB 5  37  Clay  PIGURE 6  PROVING RING CALIBRATION - COMPRESSION DIAL GAGE READING  FIGURE 8  40  A — A — A —  s t a r t i n g £ it  0  X  X  starting £ t  -  1/4"  a  o—o  starting £ t  -  1/2"  X  6  —" Total  <>  Defoi mation £ o rc G  ^ — "  Tare  0  2  4  6 Time  (seconds)  FIGURE 9  < >^-—  F o r i ;e  8  10  12  t 41  42  SIEVE ANALYSIS - MEDIUM SAND  40  /  -  M.S. = F.M . = 1.96  30-  \  20  -/ r3  9  •  r-l  Pan  No.100  No.50  No.30 Screen  •  Size  FIGURE 10b.  No.14  No .8  No .4  43  SIEVE ANALYSIS - PINE SAND  50 F.S.  P.M.  =  1.67  40 R  -  /  30 o P-.  R  20  M >•  -/  R  4  10  I  PAN  No. 100  No.50  No,30 Screen Size  FIGURE 10c.  No. 14  No .8  No .4  44  FIGURE  FIGURE  11  12  45  FIGURE 15b  47.  FIGURE 15c  i  16 A  A  A  —  starting  at 0  X  *  X —  starting E t  -  1/4"  <5  0  0  starting a t  -  1/2"  MIX  NC). 3  14  12  /  1 s  Total  c  Defo rmation Pore i  8  <  ^^^^^ 6  >  I  i  1  I  r  1  i i  •  / /  ; ]  /< / ' I  \  0  /  / 1  i  /  '  2  r  ' Tare  i  —  Pore*  _'  J  // ^  w  ¥  /  1 /  >  4 Time  6 (seconds)  PIG-TIRE 18  8  10  12  51  12  • i; •  A—A—A—  starting a t 0  X  X  starting a t - i / 4 "  o—  starting a b - 1/2"  X  o——o  MIX NO. 4  *  10  8 r t a l Defon aation Force 0  c  0}  c  o M  o <  ^_ >  ^ —  /  •  sir  • *  - —'  J  ;—  —  '—•**  —  Tare F orce  0  4  6 Time (seconds)  FIGURE 19  8  10  12  52  4  6  Time (seconds) FIGURE 20  3  10  12  A  A  starting at 0'  A—  MIX NO. 6  starting at - 1/4"  y—y<—><•—  starting at - 1/2"  :  Total Defoi mation  i  Pore e  <  ^^^^^ jS^f—  — . —  —  /<?  ^  a >  —  — ^  ^  3  —'  Tare Po::ce  ///^ 2  4  6 Time (seconds) FIGURE 21  8  10  12  54  A—A—A—  starting at 0  v/ A  starting at - 1 / 4 "  W A  \y A  starting at -  MIX NO , 7  1/2"  8  / \  Total Defoi mation Fore e  ^  r  i  © 4  y x  — >  _  —  2  Tare  0  2  4  6  Time (seconds) FIGURE 22  I?03 •ce  8  10  12  Arr-A  A  starting at 0  x—*•  X  starting at «t 1/4"  HIX  KO.  8  starting at - 1/2"  <>  Fore e  t  ^  ^  ^  ^  '  -  • ) /  /  •  • i i  S -  ^  >«•—•  i  "1  Tare ¥oi *ce  Time (seconds) FIGURE 2 3  '  56  1  10  A  A  A  y  x  x—  o  0  o  starting at 0 starting at - 1/4  MIX KG* 9  B  starting at - 1/2"  i  8  i  Total Sexor raation 6  Fore s  —•—^-^ ' J  /? \  '  r  ^ i  © 4 o u o  £4  x  yy  ///  ///  0  : f  yy •  // /y~  2  s  ^  ——-  —  j  Tar© #01  >  2  ;  4  6 Time (aocondd) FIGURE 24  8  10  12  -0  REFERENCES A 'Study o f t h e F l o w - t a b l e and t h e Slump T e s t . George A . S m i t h and S a n f o r d W. Benham J a n . 1931, p .p .420-438 A .C .2 . p r o c e e d i n g v .27 . A Study  o f F l o w and F l o w o f C o n c r e t e .  I n g e l y s e and W.R.  Johnson  J a n . 1931,'p.p .439-467 A .C .2 p r o c e e d i n g v . 2 7 . A d m i x t u r e s and - W o r k a b i l i t y o f C o n c r e t e . G. M. W i l l i a m s F e b . 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 C o n c r e t e i n t h e Mixed  Drum.  Emory D. R o b e r t s S e p t . 1931, p.p .59-72 v.28 Studies  of W o r k a b i l i t y of C o n c r e t e .  T.C. P o w e r s F e b . 1932, p . p . 419-448 v . 2 8 . Factors  o f W o r k a b i l i t y o f P o r t l a n d Cement  Concrete.  V/. H. H e r s c h e l and E.A. P i s a p i a May - J u n e . 1936 , p . p . 641-658 v . 3 2 . The A p p l i c a t i o n o f Some o f t h e Newer C o n c e p t s of Concrete Mix. •W. M. Dunagan June 1940, p . p . 649-684 v.36 . Admixtures  t o the Design  f o r Concrete.  A . C . 2 Committee 212 - Nov. 1944, p . p . 73-88 v . 4 1 . Entrained A i r - A Factor i n the Design  of Concrete  Mixes.  W. A . C o r d o n J u n e 1946, p . p . 605-620 v . 4 2 . Effect  o f M i x i n g S e q u e n c e on t h e P r o p e r t i e s o f 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 . 1 3 7 - 1 4 0 v . 4 6 .  

Cite

Citation Scheme:

        

Citations by CSL (citeproc-js)

Usage Statistics

Share

Embed

Customize your widget with the following options, then copy and paste the code below into the HTML of your page to embed this item in your website.
                        
                            <div id="ubcOpenCollectionsWidgetDisplay">
                            <script id="ubcOpenCollectionsWidget"
                            src="{[{embed.src}]}"
                            data-item="{[{embed.item}]}"
                            data-collection="{[{embed.collection}]}"
                            data-metadata="{[{embed.showMetadata}]}"
                            data-width="{[{embed.width}]}"
                            async >
                            </script>
                            </div>
                        
                    
IIIF logo Our image viewer uses the IIIF 2.0 standard. To load this item in other compatible viewers, use this url:
http://iiif.library.ubc.ca/presentation/dsp.831.1-0050615/manifest

Comment

Related Items