CEMENT AND CONCRETE FENCE POSTS. n 



PART II. 



THE EXPERIMENTS 



These experiments were conducted for the purpose of deter- 

 mining the method of building the best posts at the least cost. 



Apparatus. Various commercial molds of different shapes 

 and construction were secured. In each of these molds sev- 

 eral posts were made in order to determine the practicability of 

 the mold ; also the best combination of mixtures and reinforcements. 



The Farm Mechanics Department designed, built and used a 

 simple home made mold which makes a post of uniform size from 

 the base to the ground line with a rapid taper from the ground 

 line to the top. (See Fig. i.) 



A shed which was closed on all sides with a sliding door on the 

 east was used as the work and curing room. 



Materials The sand and gravel used was clean and 

 sharp, with all sizes of grains varying from small to large. There 

 was a very small percentage of mica in the sand, which was objec- 

 tionable. One brand of Portland cement was used for making 

 all posts. 



A total of 238 line posts and 8 corner posts were built and 

 tested during the experiment, the records of which are found in the 

 following tables : 



Cost of Materials. In figuring cost of materials the following 

 prices were used : 



Sand and gravel, Si.oo per cubic yard. 

 Cement, 60 cents per sack. 

 New reinforcement, 4 cents per pound. 

 Old barbed wire, 2 cents per pound. 



The Test. In making the test, the posts were placed under 

 as near fence conditions as possible. All line posts were set and 

 firmly tamped into the ground so that 4 feet and one inch pro- 

 jected above the surface. By means of a wire, a dynamometer was 

 attached to the post exactly 4 feet from the surface of the ground. 

 A steadily increasing force was applied to the dynamometer by 

 means of a block and tackle, until the first visible crack appeared 

 in the post when a reading was made. The force was then in- 

 creased until the post gave away completely when the final reading 

 was made. 



In making the posts enough of the mixture was provided for 

 the construction of three posts at once. The three were cured alike 

 for 60 days and were tested at the same time. The tables show 

 the average results of the test on the three posts as one. 



In the reinforcement the short wires mentioned are two feet 

 long and are placed in the post so the top extends about 12 inches 



