The forensic investigator didn't reach for a hammer or a microscope first. She reached for a saw, a diamond-blade core drill, and a copy of .
Note: Values >20% permeable voids generally indicate poor-quality concrete or a mix design error. astm c642 density absorption voids in hardened concrete
The technician then weighs the sample submerged in water (using a wire suspending it from the scale). This gives the . Then, they remove it, gently blot it with a damp towel, and weigh it again in air. This is the Saturated Surface-Dry Mass (SSD) (B) . Step 3: The Arithmetic (Calculations) With three numbers—A (dry), B (SSD), and C (submerged)—the hidden geography of the concrete is revealed. The forensic investigator didn't reach for a hammer
So, the technician brings out the hot plate. The sample is boiled in distilled water for . Boiling reduces the surface tension of the water and expands the air in the pores, driving it out. After boiling, the sample cools overnight while still submerged. The technician then weighs the sample submerged in
The trouble is that water, chlorides, and sulfates travel through these voids. Once they reach the reinforcing steel, the bridge dies from the inside.
By J. Carter, Materials Field Engineer