290 W. H. WARREN. 



INVESTIGATION in regard to the COMPARATIVE 

 STRENGTH AND ELASTICITY of PORTLAND 

 CEMENT MORTAR and CONCRETE when re- 

 inforced with STEEL RODS and when not 



REINFORCED. 



By W. H. Warren, m. inst. c.e., wh. sc, Challis Professor of 

 Engineering. 



[Read before the Royal Society of N. 8. Wales, December 3, 1902.] 



The following investigation lias been undertaken in order 

 to supply data for use in the design of armoured mortar 

 and concrete constructions, such as the Monier system, 

 and consists of tension, compression, and transverse tests 

 of mortar and concrete when reinforced with steel rods, 

 also of tests under similar conditions when not reinforced. 

 The mortar consisted of one part of Portland cement to 

 two, three and four parts of washed river sand, which had 

 been passed through a sieve of 400 and caught on a sieve 

 of 900 meshes per square inch. 



Tension Tests. — The size and shape of the test pieces 

 used for tensile tests is shown in Fig. 1, and the arrange- 

 ments for holding it in the testing machine in Pig. 2. Fig. 3 

 shows the test piece fixed in a horizontal testing machine. 

 It will be observed that the shackles are so designed that 

 the tensile stress applied is equally distributed over the 

 area of the cross section under test, which is 100 x 100 

 mm., or 4 inch x 4 inch; the length over which the elonga- 

 tions were measured is also 100 mm., or 4 inches. 



The shackles are held in a horizontal plane by means of 

 four springs which allow them to be adjusted by means of 



