Preparation
T h e a d m ix tu re s w ere p re p a re d an d used in th e m a n n e r a n d in th e a m o u n ts d escribed below :
A d m ix tu re Q w as used in th e a m o u n t of 20 ml. p e r 100 lb. of cem en t or 0.015 per cent of the adm ixture solids by weight of cement. T h e a m o u n t to be used, b ased on th e w eight of cem ent, w as m easu red o u t b y volum e a n d th e n d ilu te d w ith w a te r to m ak e 100 ml. of liq u id to be a d d e d a t th e m ixer. T h e a m o u n t of m ixing w a te r w as decreased b y 100 ml. w hen A d m ix tu re Q w as used.
A d m ix tu re R. T h e p ro p o rtio n s of th e R so lu tio n w ere: resin pow der:
249 g .; sodium h y d ro x id e; 37.4 g .; w a te r: sufficient to m ake tw o liters of th e so lu tio n .
T h e N a O H w as dissolved in a sm all a m o u n t of w a te r a n d th e n a d d ed slow ly to a suspension of th e resin pow der in w ater. S tirrin g w as con
tin u e d u n til n e u tra liz a tio n of th e resin w as com plete. T h e solution c o n ta in e d 0.1245 g. of resin p e r ml. of solution. I t w as desired to use 0.01 per cent neutralized resin by weight of the cement, so 34.3 ml. of so lu tio n w as re q u ired p e r b ag of cem ent. F ro m th e w eight of cem ent to be used in each b a tc h of concrete, th e volum e of th e so lu tio n re q u ired w as com p u te d , m easu red , a n d th e n d ilu te d w ith w a te r to a to ta l volum e of 100 ml. for ad d itio n to th e b a tc h . T h e a m o u n t of m ixing w a te r w as reduced by an eq u iv a le n t volum e.
A d m ixtu re S. T h e R a d m ix tu re w as p re p a re d in solution an d m eas
u re d o u t e x actly as described abo v e e x cep t t h a t i t w as n o t d ilu ted . C om m ercial calcium chloride (77 - 80 p e r cen t CaClf) w as w eighed o u t in th e a m o u n t of 1 p e r ce n t b y w eight of th e cem ent. A volum e of cold w a te r w as m easu red o u t, as follows:
Vol. of w a ter, m l. = — x (473.17 - R)W 94
w here : W = w eight in p o u n d s of cem en t used,
R = volum e of R so lu tio n to be used, in ml. a n d 473.17 = n u m b e r of ml. in 1 p in t.
H ence th e volum es w ere such t h a t th e volum e of th e R so lu tio n + volum e of w a te r w ould be 1 p in t p e r b a g of cem ent.
T h e cold w a te r w as a d d ed to th e CaCl2 a n d it w as s tirre d a n d h e a te d u n til so lu tio n w as com plete. T h e CaCl2 so lu tio n w as th e n allow ed to cool. Im m e d ia te ly p rio r to a d d in g to th e m ixer th e C aC k so lu tio n w as a d d e d to th e R solution a n d th e m ix tu re stirred . T h e m ix tu re w as
“ s trin g y ” w hen a d d e d to th e m ixer. W hen th is a d m ix tu re w as used th e a m o u n t of m ixing w a te r used w as decreased b y an a m o u n t eq u al to th e com bined volum es of th e R solution an d th e w a te r a d d ed to th e CaCl2
(i.e. b y 1 p in t p er b a g of cem en t). T h e a d m ix tu r e s w as u sed in th e a m o u n t of 1.06 p e r cen t b y w eig h t of th e cem en t.
A d m ix tu re T . T h e sem i-liquid beef ta llo w w as w eighed o u t in fo u r 120-g. b a tc h e s. T o each b a tc h w as a d d e d a so lu tio n co n ta in in g 50 g. of N a O H , 150 ml. of H 20 , a n d 100 m l. of alcohol. T h e m ix tu re w as th e n boiled slow ly (refluxed) u n til sap o n ificatio n w as com plete. T h e sa p o n ified m ix tu re w as th e n a d d e d to a cold s a tu ra te d so lu tio n of N a C l in w a te r to “ s a lt- o u t” th e soap. T h e soap w as th e n s e p a ra te d fro m th e im p u ritie s a n d th e s a lt so lu tio n b y v a c u u m filtra tio n . T h e soap w as d ried a t 95 C. to c o n sta n t w eig h t a n d p u lv erized b y g rin d in g in a m o rta r. T h e p ow dered soap w as w eighed o u t in th e a m o u n t of 0.01 per cent by weight of the cement an d th e n a p p ro x im a te ly 1000 ml. of w a te r w as a d d e d to th e soap. T h is m ix tu re w as h e a te d a n d s tirre d u n til th e soap w as com p le te ly dissolved. T h e soap so lu tio n w as th e n d ilu te d w ith w a rm w a te r to a volum e of 3000 ml. W h en th is a d m ix tu re wyas used, th e a m o u n t of m ixing w a te r w as d ecreased b y 3000 m l.
A d m ix tu re U w as o b ta in e d as a d ry p o w d er a n d th e a m o u n t to be used w as m easu red b y w eig h t so t h a t 1.06 per cent was added by weight o f the cement u sed (eq u al to 1 lb. p e r b a g of cem en t, as re q u ire d b y th e m a n u fa c tu re r). T h e a d m ix tu re w as a d d e d to th e b a tc h in th e p o w d er form follow ing th e a d d itio n of first 2 /3 of th e w a te r a n d befo re th e cem ent.
A d m ix tu re V (not used in in itia l phase of w ork). T h is a d m ix tu re w as d eveloped b y th e w rite r d u rin g th e pro g ress of th e w ork*. I t w as u se d in lieu of a d m ix tu re S in all ex cep t th e in itia l p h ase of th e w o rk a n d w as a d d e d to th e b a tc h in th e p o w d er fo rm in th e a m o u n t of 1.06 per cent by weight of the cement.
A d m ix tu re X . T h e paraffin oil (see list of p ro p e rtie s below ) w as received as a n oil in w hich p re c ip ita te d lu m p s of p araffin w ere su sp en d ed . T h e m ix tu re w as h e a te d on a w a te r b a th u n til th e lu m p s w ere com p le te ly m elted . A n a m o u n t of th e oil e q u a l to 0.5 per cent by weight o f the cement w as ta k e n u p in a g ra d u a te d p ip e tte a n d expelled in a th in stre a m in to th e w eighed a m o u n t of c em en t. T h e a m o u n t of c e m e n t tr e a te d v a rie d from 60 to 100 lb. p e r b a tc h . T h e c e m e n t w as th e n m ixed in a m odified Los A ngeles A b rasio n M a c h in e (from w h ich th e shelf h a d been rem o v ed ) for 500 re v o lu tio n s w ith a wre ig h t of % -in . d ia m e te r ste el b alls e q u al to 4 tim es th e w eig h t of th e cem en t. T h e cem en t w as th e n rem o v ed fro m th e d ru m , s e p a ra te d fro m th e balls, a n d placed in 5-gal. cans w hich w ere sealed ex cep t fo r p ressu re-relief valv es.
T h e cans w ere p laced in a n oven, m a in ta in e d a t a te m p e ra tu r e of 200 F.
for tw o d ay s, a n d allow ed to cool w ith th e oven for tw o d ay s. T h e y w ere
♦ P a te n t a p p lie d for.
CONCRETE CONTAINING AIR-ENTRAINING ADMIXTURES
rem o v ed fro m th e oven an d th e cem en t w eighed o u t for use in concrete on th e d a y th e c o n crete w as to be m ade. T h is aging w as s ta te d to be n e cessary b y th e ag ency recom m ending th e m aterial.
P R O P E R T IE S OF PA R R A F IN OIL W ax C o n te n t... 20 to 25 per cent Specific G ra v ity ... 0.850 to 0.857 Flash P o in t... 230 F. to 260 F.
(Cleveland Open Cup) Cold T e s t...65 F. to 75 F.
Viscosity a t 100 F ...43 to 48 (Saybolt Universal) A d m ix tu re Y w as p u rc h a se d as a liquid from a local d is trib u to r an d w as a d d ed to th e m ixer in th e a m o u n t of 1.5 gal. p e r cu. yd. (abs. vol.) of co n crete as recom m ended b y m a n u fa c tu re r fo r “ m ass” concrete. T h e a m o u n t to be ad d e d to a given b a tc h w as d e te rm in e d b y w eight so t h a t for th e follow ing c em e n t facto rs th e p er c e n t b y w eig h t of cem en t was, as follow s:
C. F . (b. per cu. yd.) Admixture, per cent
4 .5 0 2.96
5 .2 5 2.53
6.0 0 2.22
W hen a d m ix tu re Y w as u sed th e a m o u n t of m ixing w a te r w as decreased b y a n a m o u n t e q u al to th e w eig h t of so lu tio n added.
In view of th e claim b y th e m a n u fa c tu re r t h a t th is m a te ria l afforded in te g ra l curing, th e con crete m ad e w ith th is m a te ria l received no fog or w a te r curing a fte r m olding.
A d m ix tu re Z w as p u rc h a se d as a d ry pow der from th e m a n u fa c tu re r’s com m ercial sto ck in A u g u st 1944 an d th e a m o u n t to be used w as m eas- sured b y w eig h t so t h a t 1.06 -per cent was added by weight of the cement used (equal to 1 lb. p e r b a g of cem ent, as re q u ired b y m a n u fa c tu re r).
T h e a d m ix tu re w as a d d ed to th e b a tc h in th e pow der form follow ing th e ad d itio n of th e first 2 /3 of th e w a te r a n d before th e cem ent.
Cements
I t w as fo u n d to be im p ra c tic a l to o b ta in sev eral b ra n d s of com m er
cially p ro d u ced P o rtla n d cem ent co n tain in g th e desired a m o u n ts (based on a ir e n tra in m e n t) of th e v ario u s in te rg rin d a b le a d m ix tu res (Q, R , T, a n d X ) an d , as c e rta in a d m ix tu re s of th e n o n -in te rg ro u n d v a rie ty w ere to be used, it w as decided to a d d all of th e a d m ix tu re s a t th e tim e of m ixing th e con crete (except X , see descrip tio n of use above). T h e ' c em en t used w as a b le n d of eq u al p a rts of fo u r b ra n d s of cem en t m a n u
fa c tu re d com m ercially to m eet F e d eral Specifications SS-C -206a (A.S.
T .M . C 150 T y p e I I ) . P ro p e r q u a n titie s of e q u al p a rts of each of th e cem en ts w ere a d d e d to each b a tc h of concrete a t th e tim e of m ixing.
Aggregates
T h e fine ag g reg ate used w as from a single lo t of n a tu r a l siliceous sa n d from L ong Isla n d h a v in g a F .M . of 2.60. T h e coarse a g g re g a te w as C o n n e c tic u t tr a p rock of lj^ - in . m a x im u m size a n d h a v in g a F .M . of 7.0.
T h e c h a ra c te ristic s of th e ag g reg ate a re show n in T a b le 2.