﻿760 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  of 
  surface 
  or 
  deformities 
  of 
  shape, 
  and 
  their 
  upper 
  and 
  under 
  

   faces 
  must 
  be 
  practically 
  parallel. 
  

  

  6 
  Not 
  fewer 
  than 
  10 
  bricks 
  shall 
  be 
  broken, 
  and 
  the 
  average 
  

   of 
  all 
  be 
  taken 
  for 
  a 
  standard 
  test. 
  

  

  Specifications 
  for 
  crushing 
  test 
  

  

  1 
  The 
  crushing 
  test 
  should 
  be 
  made 
  on 
  half 
  bricks, 
  loaded 
  edge- 
  

   wise, 
  or 
  as 
  they 
  are 
  laid 
  in 
  the 
  street. 
  If 
  the 
  machine 
  used 
  is 
  

   unable 
  to 
  crush 
  a 
  full 
  half 
  brick, 
  the 
  area 
  may 
  be 
  reduced 
  by 
  

   chipping 
  off, 
  keeping 
  the 
  form 
  of 
  the 
  piece 
  to 
  be 
  tested 
  as 
  nearly 
  

   prismatic 
  as 
  possible. 
  A 
  machine 
  of 
  at 
  least 
  100,000 
  pounds' 
  

   capacity 
  should 
  be 
  used, 
  and 
  the 
  specimen 
  should 
  not 
  be 
  reduced 
  

   below 
  4 
  square 
  inches 
  of 
  area 
  in 
  cross-section 
  at 
  right 
  angles 
  to 
  

   the 
  direction 
  of 
  load. 
  

  

  2 
  The 
  upper 
  and 
  lower 
  surfaces 
  should 
  preferably 
  be 
  ground 
  

   to 
  true 
  and 
  parallel 
  planes. 
  If 
  this 
  is 
  not 
  done 
  they 
  should 
  be 
  

   bedded 
  in 
  plaster 
  of 
  paris 
  while 
  in 
  the 
  testing 
  machine, 
  which 
  

   should 
  be 
  allowed 
  to 
  harden 
  10 
  minutes 
  under 
  the 
  weight 
  of 
  the 
  

   crushing 
  planes 
  only, 
  before 
  the 
  load 
  is 
  applied. 
  

  

  3 
  The 
  load 
  should 
  be 
  applied 
  at 
  a 
  uniform 
  rate 
  of 
  increase 
  to 
  

   the 
  point 
  of 
  rupture. 
  

  

  4 
  l^ot 
  less 
  than 
  an 
  average 
  obtained 
  from 
  five 
  t^sts 
  on 
  five 
  dif- 
  

   ferent 
  bricks 
  shall 
  constitute 
  a 
  standard 
  test. 
  

  

  It 
  was 
  resolved 
  by 
  the 
  commission 
  that 
  " 
  from 
  the 
  experimental 
  

   work 
  done 
  so 
  far 
  by 
  this 
  commission, 
  or 
  by 
  others 
  so 
  far 
  as 
  is 
  

   known 
  to 
  us, 
  in 
  the 
  application 
  of 
  the 
  cross-breaking 
  and 
  crushing 
  

   tests 
  to 
  paving 
  brick, 
  it 
  is 
  not 
  possible 
  to 
  show 
  any 
  close 
  relation- 
  

   ship 
  between 
  the 
  qualities 
  necessary 
  for 
  a 
  good 
  paving 
  material 
  

   and 
  high 
  structural 
  strength 
  as 
  indicated 
  by 
  either 
  of 
  these 
  tests 
  ". 
  

  

  JSffect 
  of 
  structure 
  on, 
  wearing 
  power 
  of 
  paving 
  hricJc^ 
  

   Hecent 
  experiments 
  by 
  Prof. 
  Edward 
  Orton 
  jr 
  on 
  bricks 
  made 
  

   from 
  the 
  same 
  shale, 
  but 
  molded 
  on 
  different 
  machines 
  and 
  burned 
  

  

  ' 
  Clayworker, 
  February 
  and 
  March 
  1897. 
  

  

  