SCEBs - University of Colorado Boulder

each specimen‟s bulk unit weight. Typical unit weights of the SCEBs were measured to
be approximately 127 pounds per cubic foot (pcf), with a minimum value of 125.8 pcf
and a maximum of 127.6 pcf. This corresponds to a full size block weighing
approximately 40 to 45 pounds. A full listing of bulk unit weights and other block
specifications can be found in Appendix 8.2.1.
For each ratio, ten SCEBs were produced. None of the SCEBs appeared to
exhibit significant imperfections after ejection from the Small Block Press. Four were
tested during the 28 day curing period at weekly intervals, leaving six blocks available
for the durability tests. The compression tests were performed over a 6 week period (4
weeks of curing and 2 weeks for the durability tests).
4.1.2.4. UCS Testing
An Instron materials testing machine available in the Integrated Teaching and
Learning Laboratory at CU Boulder and equipped with a 50 kN (11.2 kips) load cell, was
used to measure the unconfined compressive strength of the SCEBs. The New Mexico
Earthen Building Materials Code testing standards were followed as closely as possible.
The dimensions given for full-size SCEBs were adjusted to accommodate the quarter-size
blocks. A controlled strain rate of 0.0003 in/sec was used rather than a controlled stress
rate. The strain rate used did not allow for the stress rate to surpass the rate given by the
followed code.
The SCEBs tested for durability were allowed to cure in a controlled environment
(~92.5% relative humidity, ~72 o F) for 28 days before any durability strength testing
began. This was to allow the cement strength to fully develop thus allowing measured
strength values to be independent of cement strength changes. Tests were performed at
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