CEM200 lab 4,5, & 6

Concrete Construction Lab Overview for Quiz 2 - Week 13 Labs 4, 5, and 6

Introduction

The document presents an overview of the topics covered in the concrete construction labs at California State University Long Beach, specifically focusing on Quiz 2, encompassing content from Labs 4, 5, and 6, as well as a video presentation on critical civil engineering topics.

Agenda for Today

The key points of the agenda include:

  • Syllabus Update: A review of any changes to the course syllabus.

  • Quiz Format: Explanation of the format and structure of Quiz 2.

  • Preparation Guide: Guidelines on what materials and topics to study.

  • Labs 4, 5, and 6: Summary of the content and objectives of labs.

  • Sample Questions: Examples of questions that may appear on the quiz.

Quiz #2 Format

  • Total Number of Questions: 25 questions or statements, for a total of 24 points, plus 1 bonus question worth 1.5 points.

  • Types of Questions: Multiple choice or True/False formats.

  • Materials Allowed: No notes or other support materials permitted during the exam.

  • Time Limit: 15 minutes to complete the quiz, administered via Canvas in class.

Preparation Guide - Materials

Portland Cement Concrete (PCC) Materials

  • Portland Cement (PC): The only type utilized is Type I/II.

  • Additional Materials: Includes sand, coarse aggregate, and water.

  • Admixtures: Various additives are noted, such as those improving high-early strength, providing sulfate corrosion resistance, enhancing plasticity, etc.

Preparation Guide – Labs 4 & 5

  • Batching Materials: Definitions of key concepts:
      - Concrete: A composite material made of aggregates and cement.
      - Mortar: A mixture of cement and sand, typically used for binding bricks.

  • Curing vs. Drying: Hydration is essential for the concrete's curing process, allowing strength to develop.

  • Strength Comparison: A discussion on why concrete is generally stronger than mortar due to its composition and the use of aggregates.

  • Lab Conditions: Examples of unusual conditions encountered in the lab, which may affect the results.

Preparation Guide - Lab 6

  • Gradation of Aggregates: Application of aggregate size distribution for both concrete and mortar.

  • Moisture Issues: Discussion on the effects of moisture in the mixing process.

  • Optimal Coarse Aggregate: Identification of the best types of coarse aggregate for Portland Cement concrete and asphalt concrete.

  • Class Observations: Review of any unusual lab conditions that were witnessed by the class during experiments.

Sample Quiz Questions

  • Question on Hardened Portland Cement Concrete Attributes:
      The key attributes of hardened or cured Portland cement concrete that a civil design engineer must focus on include volume stability, elasticity, compressive strength, and impermeability. The correct response could be that all these attributes hold true.

  • Mortar Attributes: Evaluating what is most significant in hardened or cured portland cement mortar with similar potential answers—likely concluding all are relevant attributes.

  • Sieve Analysis: Identifying what constitutes a good gradation curve illustrated in a sieve analysis. A well-distributed results line is characterized as an “S” curve, reflecting a balance across different aggregate sizes.

  • Strength Determinants of Hardened Portland Cement Mortar: Factors influencing strength encompass the water/cement ratio of the mix, quality of curing, and the paste quality of the portland cement, suggesting all are true.

  • Unusual Lab Conditions: Recognition of factors that could impact lab results, including improper measurements and aggregate angularity, confirming that all statements may indeed apply.

  • St. Francis Dam Failure Questions: A case study on the St. Francis Dam failure of 1928, discussing its causes which could range from poor mixing and curing to geological misunderstandings, again indicating that all causes provided may indeed be relevant.

  • Material Capture in Sieve Analysis: In sieve analysis, materials not retained in a sieve may be found in the lid, smaller sieve, or pan, requiring knowledge of all possibilities.

  • Compressive Strength Testing: A discussion statement posing that compressive strength is always tested as expected if w/c ratios are properly understood, requiring students to discern the truth value of this statement.