"""''"'t-r • ..,..,.,."" wire strain gauges have used to measure of the crack zone (MCZ) of mortar and cement paste. As ~~-~,......i~ increases, the MCZ ·grows and the structure parameter increases. of MCZ decreases with increasing strength. For a given…
"""''"'t-r • ..,..,.,."" wire strain gauges have used to measure of the crack zone (MCZ) of mortar and cement paste. As ~~-~,......i~ increases, the MCZ ·grows and the structure parameter increases. of MCZ decreases with increasing strength. For a given water/cement ratio, the concrete is the longest, of mortar second, shortest. of MCZ is m concept of micro crack defined F.O. Slate et (1968) has been employed in regards 0 .1 mm as boundary of micro crack extreme tensile strain of concrete as lower. When a crack is wider extreme strain, basic elements of do not return to their original positions even unloaded ( ) E cement No. W/C Materials Mechanical pt up1;;1 Uv.> Enhancer Cement Water Sand Gravel NF* fc** f1 E cu ( 1) ( µ ) 0.30 55 495 165 542 1264 5.5 69.4 4.66 3.738 124.6 2 0.30 --- 550 165 542 1264 5.5 58.9 4.22 3.622 16.5 3 0.40 --- 450 575 1222 -- 49.7 2.15 3.590 60. 4 0.45 --- 292 1297 --- -- 53.2 3.01 .196 252.0 5 0.33 --- 1295 427 --- --- -- 57.5 2.