20 
The Colorado Experiment Station. 
Strength of cement posts compared to new wood posts tested under 
like conditions. 
KIND OF POST 
sizp: OF POST 
BREAKING STRENGTH 
REMARKS 
(1) Best cement post 
tested 
5x5 in. at ground line 
tapering to 3x3 in. at top 
322 lbs. 
(2) Cement 
Same as above 
307 lbs. 
(3) Cement 
4x4 in. at base tapering 
to 3x3 in. at top 
185 lbs. 
The post was 3.6x 
3.6 in. at ground 
(4) Split cedar (new) 
3.6x3.6 in. at ground 
line 
613 lbs. 
Same size at ground 
as No. 3 above 
White pine (new) 
4x4 in. at ground line 
2000 lbs. 
Red spruce (new) 
4)^x4)4 in. at ground 
line 
2400 lbs. 
Red spruce (new) 
5x5 in. at ground line 
3350 lbs. 
CONCLUSIONS. 
Poured posts are easier to make than tamped ones. They are some¬ 
what more expensive because one mold will make but one poured post per 
day, while the same mold may be used for making as many tamped posts 
as the builder can mix and tamp in the same time. 
According to the tests made poured posts are a little over 2 5 per cent 
stronger than tamped ones of the same size, mixture and reinforcement. 
Poured posts are not so porous as the tamped ones and are therefore 
more nearly water proof, thus making them better able to withstand the 
action of frost and alkali. 
The poured post is enough better in every respect to justify its con¬ 
struction and use in preference to the tamped one. 
Most commercial molds make a post which tapers from the base to 
the top, but the most economical mold is one which casts a post as large 
at the ground line as at the base, tapering from the ground line to the 
top. For a description of this form of mold, see Fig. 4. 
The best form of post is one which is equally strong from all direc¬ 
tions. The square, or round post, fulfills this requirement. The tri¬ 
angular post does not meet the requirements because it cannot be econ¬ 
omically constructed so as to be equally strong from all directions. 
To be economical, the amount of reinforcement should be in propor¬ 
tion to the size of the post and strength of the mixture. See tables. 
The material used for reinforcement should be strong, light and 
rough enough to permit the mixture to get a firm grip upon it. It should 
be very rigid, with little or no tendency to spring or stretch. 
The smooth reinforcement tends to slip even if hooked at the ends. 
Two or more wires twisted together make as satisfactory a reinforce¬ 
ment as can be obtained. 
Crimped wire tends to straighten and thereby breaks pieces out of 
the post at the point of greatest stress. 
The reinforcement should be placed in each corner of the post at a 
depth of from % to % of an inch from the surface. 
There are several commercial wire fasteners now found on the 
market, the most of which are either cumbersome or expensive. For a 
simple and satisfactory fastener, see cut of fasteners. (Fig. 5, A.) 
The posts should be cured in the shade for at least 60 days, the first 
30 days of which they should be sprinkled daily. 
