NHI SAFETY INSPECTION OF IN-SERVICE BRIDGES Complete 200-Question Practice Exam Study

NHI SAFETY INSPECTION OF IN-SERVICE BRIDGES Complete 200-Question Practice Exam Study Question 1. Definition: The sound of “sound” concrete when tapped with a hammer A. Thumping B. Pitting C. Crunching D. Pinging Correct Answer: D Rationale: Sound concrete produces a sharp, metallic “pinging” sound when struck with a hammer. This indicates good bond and integrity. Unsound concrete (delaminated or spalled) produces a dull, hollow thumping sound. Question 2. Definition: The sound of delaminated or “unsound” concrete when tapped with a hammer A. Pinging B. Hollow thumping C. Scratching D. Rattling Correct Answer: B Rationale: Delaminated concrete separates along a plane parallel to the surface, creating a void that produces a dull, hollow “thumping” sound when struck. This is a primary field indicator of subsurface delamination. Question 3. Definition: A type of concrete deterioration characterized by small, shallow, broken pockets on the surface A. Scaling B. Spalling C. Cracking D. Potholing Correct Answer: A Rationale: Scaling is the loss of surface mortar or paste, creating small, shallow depressions typically less than 1 inch deep. It is caused by freeze-thaw cycles, deicing chemicals, or poor curing practices. Question 4. Definition: A concrete deterioration where fragments break away from the surface, forming depressions larger than 1 inch in diameter A. Scaling B. Spalling C. Efflorescence D. Delamination Correct Answer: B Rationale: Spalling involves the breaking away of larger concrete fragments, creating depressions greater than 1 inch in diameter and often exposing reinforcing steel. It is more severe than scaling and typically requires repair. Question 5. Definition: The separation of concrete along a plane parallel to the surface, forming a layered fracture A. Scaling B. Spalling C. Delamination D. Crazing Correct Answer: C Rationale: Delamination is a horizontal fracture parallel to the concrete surface, often caused by corrosion of reinforcing steel or freeze-thaw cycles. It creates a void beneath the surface that may not be visible until it spalls. Question 6. Definition: A white, powdery crystalline deposit on concrete surfaces caused by water leaching through the material A. Rust stain B. Efflorescence C. Calcite deposit D. Leaching residue Correct Answer: B Rationale: Efflorescence is a whitish, crystalline deposit on concrete surfaces formed when soluble salts are carried to the surface by water and then deposited as the water evaporates. It is a visual indicator of moisture movement through concrete. Question 7. Definition: The deterioration of concrete caused by chemical reactions between aggregate and alkalis in cement A. Alkali-silica reaction (ASR) B. Carbonation C. Sulfate attack D. Frost action Correct Answer: A Rationale: Alkali-silica reaction (ASR) is a chemical reaction between reactive silica in aggregates and high-alkali cement paste. It produces a gel that expands when exposed to moisture, causing map cracking and spalling. Carbonation and sulfate attack are different deterioration mechanisms