Historic brick buildings from the 19th century were long considered highly susceptible to damage from freeze-thaw cycles, particularly in regions...
GMAT Craft and Structure : (Structure) Questions
Historic brick buildings from the 19th century were long considered highly susceptible to damage from freeze-thaw cycles, particularly in regions with harsh winters. Experts assumed that the porous nature of older bricks would make them especially vulnerable to water infiltration and subsequent cracking. However, recent analysis by structural engineer Maria Santos and her team revealed that these buildings possess unexpected resilience mechanisms. The mortar joints, originally thought to be weak points, actually allow controlled movement that relieves stress. Additionally, the lime-based mortars used historically have self-healing properties that can seal minor cracks over time.
Which choice best describes the main purpose of the text?
To present research that challenges concerns about the vulnerability of historic brick buildings to freeze-thaw damage
To explain how lime-based mortars function as protective mechanisms in 19th-century construction
To discuss the methods structural engineers use to assess damage in historic buildings
To describe how freeze-thaw cycles have altered the appearance of historic brick buildings over time
Step 1: Decode and Map the Passage
Create Passage Analysis Table
| Text from Passage | Analysis |
|---|---|
| "Historic brick buildings from the 19th century were long considered highly susceptible to damage from freeze-thaw cycles, particularly in regions with harsh winters." |
|
| "Experts assumed that the porous nature of older bricks would make them especially vulnerable to water infiltration and subsequent cracking." |
|
| "However, recent analysis by structural engineer Maria Santos and her team revealed that these buildings possess unexpected resilience mechanisms." |
|
| "The mortar joints, originally thought to be weak points, actually allow controlled movement that relieves stress." |
|
| "Additionally, the lime-based mortars used historically have self-healing properties that can seal minor cracks over time." |
|
Provide Passage Architecture & Core Elements
Main Point: Recent research challenges long-held assumptions about historic brick buildings by revealing they actually have resilience mechanisms against freeze-thaw damage.
Argument Flow: The passage follows a classic "old view vs. new findings" structure. It first establishes what experts long believed about these buildings' vulnerability and why they believed it, then presents recent research that contradicts this view with specific evidence about how these buildings actually protect themselves.
Step 2: Interpret the Question Precisely
What's being asked? The main purpose of the entire text - what the author's overall goal was in writing this passage.
What type of answer do we need? A statement that captures the author's primary intention or objective in presenting this information.
Any limiting keywords? "Main purpose" tells us we need the overarching goal, not a detail or secondary point.
Step 3: Prethink the Answer
- The right answer should capture the shift from old assumptions to new research findings
- The right answer should recognize that the passage is fundamentally about challenging or contradicting previous beliefs
- The right answer should acknowledge that the focus is specifically on the vulnerability/resilience question
- So the right answer should indicate that the passage presents research that challenges or contradicts previous concerns about these buildings' vulnerability to freeze-thaw damage
To present research that challenges concerns about the vulnerability of historic brick buildings to freeze-thaw damage
✓ Correct
- Perfectly captures the passage structure: old "concerns about vulnerability" being "challenged" by new "research"
- Matches our prethinking exactly
To explain how lime-based mortars function as protective mechanisms in 19th-century construction
✗ Incorrect
- Focuses only on lime-based mortars, which is just one mechanism mentioned
- Too narrow - the passage's main purpose isn't to explain how mortars work, but to challenge assumptions about overall building vulnerability
To discuss the methods structural engineers use to assess damage in historic buildings
✗ Incorrect
- The passage never discusses assessment methods or how engineers evaluate damage
- Completely misses the passage's actual focus on challenging assumptions
To describe how freeze-thaw cycles have altered the appearance of historic brick buildings over time
✗ Incorrect
- The passage doesn't describe how freeze-thaw cycles have altered building appearance over time
- Focuses on resilience mechanisms that prevent damage, not on damage that has occurred