Laserfiche WebLink
7-�4-04; i7:40 ;Lester Bulldin� ;3203955376 p i4/ 28 <br /> Article Request Page Page 12 of 26 <br /> H/D ratio has on compressive strength,test values were multiplied by the following compressive <br /> strength modifying factor. <br /> Compressive Strength Modifying Factor=0.921 (H/D) 0.1186 [2] <br /> Equation 2 is applicable for H/D ratios between 1.50 and 2.50 and is basecl on a regression of data <br /> presented by Johnson(1943). <br /> Average values for cores removed&om each foofiing are compiled in Table 3. Figures 1 l, 12 and <br /> 13 contain plots of these average values for water trealments A,B and C,respectively. <br /> The differences between these averages and individual core values from Appendix A,when <br /> squared and summed,produces a total residual sum of squazes of 16,736,0221bf1/in4 for the 180 <br /> residuals.With 126 degrees of freedom(180-54)this corresponda to a pooled stanciard error of <br /> 364.41bf/in2.In other words,we would expect compressive strength values for a set of cores <br /> removed from the same footing to have a standard deviation of 364.41bf/in2. <br /> Table 3 Average Compressive Strength of In-Situ Hydrated Concrete <br /> Footings Footings Footings <br /> T� Removed Removed Removed <br /> ��tr°�t) After 4 After 12 After 24 <br /> Week Weeka Weeks <br /> Top Middle Bottom Top Middle Bottom Top Middle Bottom <br /> Average <br /> Foodng <br /> Compressive <br /> Strength, <br /> lbf/in2 <br /> 1 (A) 3107 3214 1448 3156 3919 2713 4507 3752 2460 <br /> 2(A) 2485 2980 1581 4097 3162 3369 ' 4354 3867 2780 <br /> 3 (B) 3016 2736 1227 3895 3366 3176 3973 4019 3400 <br /> 4(B) 3324 3297 1279 4073 4053 1870 4049 4112 1748 <br /> 5(C) 3604 2722 2206 2919 3799 2488 2811 4022 3230 <br /> 6(C� 3116 2617 2351 2636 3037 2802 2571 3848 2889 <br /> Level of <br /> Probability at <br /> Which <br /> Observed <br /> Difference <br /> Between <br /> Replicates is <br /> Significant'� <br /> 1 &2(A) 5.2% 39.9% 58.0% 3.4% 6.4% 9.2% 63.4% 71.9°/a 34.3% <br /> 3 &4(B) 27.7% 7.2% 90.7% 58.2% 8.2% 2.9% 81.1% 75.2% 0.2% <br /> 5 &6(C) 10.7'�0 69.$% 59.4% 39.5% 6.3% 35.1% 46.5% 59.0% 31.6% <br /> http://asae.frymulti.com/request2.asp?JID=S&AID=14082&CII�1nv2003&v=&i=&T=1 6/4/2004 <br />