DateLaboratory Testing of Portland Cement Concrete Patch Material ...

Figure 11. Length Change TestingTwo gauge studs are embedded into each end of the concrete (top). The feet of the comparator are moveduntil they slide into the top of each stud and the measurement of the specimen is recorded (bottom).The length change test results, which are the averages of three rectangular prisms for eachsample, are shown in Table 9 below and Figure 12 on the following page. At 90 days, thepatch material modified with Komponent (Sample 3), which showed slight expansion in thechange in height test of Phase I after 7 days (which tested mortar only), showed moreshrinkage than the control after 90 days. The other modified patch materials (containingType K cement, Denka CSA #20, and Tetraguard AS20) showed a reduction in shrinkagecompared to the control, with the Tetraguard AS20 modified patch material showing theleast amount of shrinkage after 90 days (approximately 42 percent less than the controlmix).Table 9. Length Change Test ResultsSAMPLEMODIFIED PATCHLENGTH CHANGE (%)NUMBER MATERIAL DESCRIPTIONS 3 DAYS 7 DAYS 28 DAYS 56 DAYS 90 DAYS1 Mn/DOT 3U18 (CONTROL) -0.0064 -0.0150 -0.0284 -0.0377 -0.03962 Mn/DOT 3U18 w/ Type K Cement 0.0016 -0.0038 -0.0236 -0.0350 -0.03873 Mn/DOT 3U18 w/ Komponent -0.0013 -0.0052 -0.0244 -0.0362 -0.04084 Mn/DOT 3U18 w/ Denka #20 (50.56 lb/yd 3 or 30 kg/m 3 ) -0.0050 -0.0129 -0.0286 -0.0328 -0.036710 Mn/DOT 3U18 w/ Tetraguard AS20 0.0035 -0.0033 -0.0138 -0.0213 -0.0230Negative length change values indicate a change in length in the negative direction, or shrinkage.25