90 KANSAS ACADEMY OF SCIENCE. 



NOTES ON SOME KANSAS PAVING BRICK. 



By F. O. Marvin, University of Kansas, Lawrence. 

 Read before the Academy, at Topeka, December 30, 1904. 



T?OR the last four or five years, the writer has done considerable 

 -*- work in the University testing laboratories on Kansas paving 

 brick from several plants, and, for the sake of comparison, on a few 

 brands of established reputation from other states. The results of this 

 work, in part; have been grouped and studied, and are presented in 

 the tables and diagrams incorporated in this paper. 



Good paving brick must be sound, homogeneous, little subject to 

 weather action, strong enough to bear the loads that come upon them, 

 tough enough not to chip or fracture under impact, and hard and co- 

 hesive enough to resist the abusive effect of traffic. 



The tests that have been generally used are four : (1) Absorption ; 

 (2) crushing strength; (3) transverse strength; (4) the rattler test. 

 Of these, the first is no longer used. It has been quite well estab- 

 lished that any brick, whether porous or close grained, which will 

 meet the requirements of the other tests, will have strength enough 

 to withstand the action of freezing. It has also been found, through 

 Investigation on a large scale, by committees of the National Brick 

 Manufacturers' Association, that the crucial test is the last named ; 

 and, also, that the tests for crushing and transverse strength are 

 valuable through furnishing some knowledge of internal structure of 

 brick. 



The results of transverse tests are given in table I, and of crush- 

 ing tests in table II. The Neodesha brick were samples made in Ohio 

 from Neodesha shale, before any brick plant was located at this place, 

 and are to be taken only as an indication of what the shale-bed might 

 yield. 



Back of the tests on Leavenworth brick lies a story of some 

 months of experimentation in trying to improve the quality of the 

 output and to meet a certain specification as to transverse strength 

 required by the city engineer of Leavenworth. 



The clay-bank at Leavenworth is one that is fat ; that is, having too 

 much alumina and too little silica. The brick made from it are too 

 brittle and possess a bad structure. The auger machine that drives 

 the clay through the dies gave a rotary motion to the clay stream, re- 

 sulting in an internal series of concentric layers, which would sepa- 

 rate to some degree during the burning process. The modification of 



