﻿LIMESTONES 
  OF 
  NEW 
  YORK 
  AND 
  THEIR 
  ECONOMIC 
  VALUE 
  417 
  

  

  Kesulfs 
  replaced 
  by 
  Prof. 
  Tetmajer 
  in 
  1894/ 
  

  

  Number 
  of 
  cem. 
  

  

  

  % 
  of 
  plaster 
  

   paris 
  added 
  

  

  Strength 
  of 
  sand 
  briq 
  

   sq. 
  in. 
  

  

  1-3 
  lb. 
  

  

  

  

  

  

  3d. 
  

  

  7d. 
  

  

  28 
  d. 
  

  

  

  

  f 
  

  

  .0 
  

  

  t 
  . 
  . 
  . 
  

  

  160 
  

  

  248 
  

  

  

  

  

  1.0 
  

  

  2.0 
  

  

  

  212 
  

   167 
  

  

  298 
  

  

  

  

  254 
  

  

  

  

  

  .0 
  

  

  174 
  

  

  285 
  

  

  307 
  

  

  

  

  

  .5 
  

  

  225 
  

  

  305 
  

  

  344 
  

  

  

  

  

  1.0 
  

  

  227 
  

  

  320 
  

  

  408 
  

  

  

  

  

  1.5 
  

  

  2.0 
  

  

  230 
  

   182 
  

  

  381 
  

  

  290 
  

  

  399 
  

  

  

  

  400 
  

  

  

  

  

  2.5 
  

  

  184 
  

  

  295 
  

  

  390 
  

  

  

  

  { 
  

  

  3.0 
  

  

  115 
  

  

  235 
  

  

  369 
  

  

  Results 
  of 
  Candlot 
  in 
  

  

  1891. 
  & 
  

  

  

  

  

  

  

  . 
  

  

  

  

  Sulfate 
  lime 
  

  

  

  

  Mortar 
  

  

  Time, 
  d. 
  

  

  % 
  »>• 
  

  

  1% 
  

  

  2% 
  

  

  3% 
  

  

  4% 
  

  

  [eat 
  cem. 
  briq 
  

  

  ••■J 
  7 
  

  

  1 
  28 
  

  

  485 
  

   673 
  

  

  645 
  

  

  738 
  

  

  533 
  

  

  674 
  

  

  435 
  

   790 
  

  

  264 
  

   483 
  

  

  cement 
  to 
  3 
  sand 
  briq 
  

  

  ••1 
  7 
  

  

  i 
  28 
  

  

  223 
  

  

  333 
  

  

  252 
  

   377 
  

  

  263 
  

  

  377 
  

  

  185 
  

   367 
  

  

  126 
  

  

  201 
  

  

  Lewis 
  considers 
  these 
  results 
  remarkable 
  as 
  regards 
  strength 
  

   and 
  not 
  explained. 
  

  

  Candlot 
  shows 
  in 
  a 
  series 
  of 
  experiments 
  that 
  the 
  slow 
  set 
  is 
  

   due 
  to 
  the 
  fact 
  that 
  " 
  the 
  sulfate 
  in 
  conjunction 
  with 
  free 
  lime 
  

   present 
  in 
  the 
  cement 
  prevents 
  hydration 
  and 
  reaction 
  of 
  the 
  

   aluminate 
  of 
  lime. 
  As 
  it 
  is 
  this 
  salt 
  which 
  determines 
  the 
  set, 
  

   the 
  cement 
  accordingly 
  becomes 
  slow 
  setting. 
  The 
  necessity 
  of 
  

   free 
  lime 
  being 
  present 
  is 
  shown 
  by 
  the 
  fact 
  of 
  its 
  slow 
  set 
  dis- 
  

   appearing 
  as 
  the 
  lime 
  becomes 
  hydrated 
  by 
  exposure." 
  

  

  No 
  advantage 
  in 
  strength 
  due 
  to 
  the 
  addition 
  of 
  sulfates 
  

   is 
  gained 
  in 
  long 
  time 
  tests. 
  

  

  Burning 
  portland 
  cement 
  

  

  The 
  furnace 
  practice 
  is 
  quite 
  varied 
  at 
  the 
  present 
  time 
  in 
  

   America. 
  The 
  style 
  of 
  the 
  kiln 
  first 
  used 
  for 
  portland 
  cement 
  in 
  

  

  a 
  Mitth. 
  d. 
  Ans. 
  zur 
  Prufung 
  v. 
  Baumaterialien, 
  7 
  Hft. 
  1894, 
  p. 
  39. 
  

   fcCiment 
  et 
  Chaux. 
  Hydrauliques, 
  Paris 
  1891, 
  p. 
  254. 
  

  

  