Aula Prática sobre BLOCOS CERÂMICOS PARA ALVENARIA ESTRUTURAL E DE VEDAÇÃO - MÉTODOS DE ENSAIO

Name: Aula Prática sobre BLOCOS CERÂMICOS PARA ALVENARIA ESTRUTURAL E DE VEDAÇÃO - MÉTODOS DE ENSAIO
Uploaded: 2020-10-28T04:42:45.000Z
Duration: 2 h 28 min 43 s

Introduction to Ceramic Blocks

Overview of the Lesson

The lesson focuses on ceramic blocks used for structural and partition walls, referencing NBR 15270-3 standards.

Emphasis is placed on the importance of ceramic blocks in civil construction.

Types of Ceramic Blocks

Discussion includes structural blocks and their specific uses, highlighting differences between them and partition blocks.

Students are reminded that practical class materials are available online for download to aid in calculations and notes.

Basic Definitions and Characteristics

Block Definitions

Basic definitions of what constitutes a block are introduced, differentiating between structural and partition blocks.

Partition ceramic blocks are primarily designed for horizontal use but can also be made for vertical applications.

Structural Block Usage

Structural ceramic blocks must always be oriented with holes vertically to ensure maximum mechanical resistance.

The primary function of partition blocks is not to bear vertical loads significantly exceeding their own weight.

Practical Class Details

Initial Measurements

Introduction to basic measurements such as gross area (total dimensions) versus net area (after accounting for holes).

Explanation of how these areas affect the application of mortar during installation processes.

Types of Ceramic Blocks Explained

Two main types discussed: structural and non-load-bearing (partition) blocks, with emphasis on their different properties regarding mechanical stress resistance.

Design Variations in Ceramic Blocks

Structural vs Non-load Bearing Blocks

Description of various designs including those with perpendicular holes which influence their application in construction projects.

Examples of Different Designs

Visual examples provided showing variations in geometry among different types of ceramic blocks, including circular shapes that allow for utility installations like plumbing.

Conclusion on Block Characteristics

Importance of Proper Installation

Highlights the significance of correct installation techniques to prevent issues such as excessive moisture absorption leading to damage over time due to improper mortar usage or block saturation.

This structured approach provides a comprehensive overview while allowing easy navigation through key concepts discussed within the transcript.

Overview of Structural and Ceramic Blocks

Types of Structural Blocks

Discussion on various types of structural blocks, including perforated ceramic blocks with circular holes.

Introduction to concrete blocks that share similar geometries with ceramic blocks, emphasizing their utility in construction.

Explanation of how specific block shapes are used for constructing beams and arches, highlighting the importance of geometry in design.

Characteristics of Autoclaved Concrete Blocks

Description of autoclaved concrete blocks, also known as "lightweight concrete blocks," which are made from a mixture that provides significant weight reduction.

Benefits include high productivity due to precise dimensions and ease of installation without damaging the material during cutting.

Evaluation and Identification Process

Transition to evaluating different types of ceramic blocks, focusing on horizontal sealing blocks for practical assessments.

Overview of a testing batch consisting of 13 blocks, noting the importance of identifying manufacturer details and specifications.

Importance of Dimensional Tolerances

Emphasis on the significance of dimensional tolerances in block production, including visual characteristics and potential defects.

Discussion on how deviations from specified dimensions can impact project outcomes, particularly regarding masonry work.

Practical Assessment Procedures

Outline for assessing dimensional tolerances such as width, height, length, and wall thickness against established standards.

Introduction to a practical evaluation phase where researchers will analyze product identification based on manufacturer markings.

Product Identification Insights

Clarification that not all tested samples belong to the same lot; they represent various types from different suppliers for comparative analysis.

Initial steps involve examining product markings for identification purposes before proceeding with detailed measurements.

Overview of Block Manufacturing and Quality Control

Key Aspects of Block Production

The manufacturing date is crucial, with a specific mention of January 30 as the production date for the blocks. Proper identification and dimensions are mandatory for compliance.

There is a notable variation in production quality among different companies, highlighting the importance of organized processes to ensure consistent quality control.

Visual characteristics of blocks are discussed, emphasizing that any imperfections or issues must be identified during production to maintain standards.

Issues Affecting Block Quality

Problems such as breakage can occur due to various factors including transportation and handling; it’s essential to monitor these aspects closely.

Uneven burning during the firing process can lead to color variations in blocks, which may not necessarily indicate inferior quality but rather differences in exposure to heat sources.

Material Composition and Its Impact

The presence of iron hydroxide in clay affects color outcomes; thus, not all lighter-colored blocks are indicative of lower quality.

Loose grains on block surfaces suggest inadequate ceramic mass dosage during production, which can compromise structural integrity.

Production Process Insights

Inadequate plastic mass composition can lead to deformities; proper water content is critical for maintaining shape and strength during firing.

Blocks may exhibit rebarb due to processing errors; this could pose risks during handling by users.

Evaluation Criteria for Blocks

Ceramic blocks should not display systematic defects like surface irregularities that hinder their intended use.

A rejection criterion based on observed defects is established: if a batch shows significant issues (e.g., five out of thirteen), it may be deemed unacceptable.

This structured overview captures key discussions from the transcript regarding block manufacturing processes, quality control measures, material impacts, and evaluation criteria.

Discussion on Block Dimensions and Specifications

Importance of Manufacturer Specifications

The speaker emphasizes the need to select a logo from the same manufacturer to ensure consistency in quality.

It is noted that there are 13 editions of blocks, highlighting the importance of observing dimensions accurately.

Measurement Insights

Measurements for block height average around 190 mm, with specific values ranging between 189 mm and 191 mm.

Length measurements indicate an average of approximately 234 mm, with individual blocks measuring between 233 mm and 235 mm.

Tolerance Levels

The discussion includes tolerances for height (190 ±5 mm) and length (240 ±5 mm), indicating potential issues if specifications are not met.

The speaker stresses that incorrect dimensions may require additional blocks to complete construction, affecting project timelines.

Wall Thickness Standards

A focus on wall thickness reveals that the minimum requirement is set at 6 mm; current measurements show some blocks at only 5.5 mm.

There’s a critical note about compliance with standards regarding wall thickness for structural integrity.

Structural Integrity Concerns

The speaker explains how insufficient wall thickness can compromise mechanical resistance, leading to potential failures in load-bearing capacity.

Emphasis is placed on ensuring adequate thickness to support loads effectively without transferring undue stress onto other structures.

Quality Control Measures

A discussion on squareness and purity of block faces highlights the need for precise measurements during construction.

Observations are made regarding diagonal measurements to ensure uniformity across all sides of the blocks.

Material Consumption Implications

Poorly aligned or uneven surfaces can lead to increased material consumption during installation due to adjustments needed for proper fitting.

Final Measurement Considerations

The importance of accurate measurement techniques is reiterated, particularly using calipers at specific points on the block surfaces.

This structured summary captures key discussions from the transcript while providing timestamps for easy reference.

Building Construction Insights

Importance of Block Alignment and Deviation

Discusses the implications of a 2mm deviation over a height of 30 meters in building construction, emphasizing how even small errors can accumulate significantly.

Highlights the challenge of maintaining uniformity across all blocks, noting that deviations can lead to structural issues as one ascends through the floors.

Explains the necessity for compensating weight distribution when blocks are not aligned properly, which could affect overall stability.

Introduces calculations related to block dimensions and their impact on square meter requirements for construction projects.

Mentions estimating facade dimensions and volume requirements for materials based on block alignment.

Material Usage and Quality Considerations

Addresses the amount of mortar needed to correct imperfections in blocks, stressing that quality control is crucial for minimizing material waste.

Warns against cost-cutting measures that compromise block quality, which can lead to increased expenses due to higher mortar usage during installation.

Reiterates the importance of verifying block dimensions before use, linking this practice directly to project success and structural integrity.

Water Absorption Testing Procedures

Shifts focus to water absorption tests for blocks, explaining its relevance in assessing material performance under various conditions.

Describes initial drying processes in an oven followed by testing water absorption rates after specific time intervals.

Emphasizes evaluating geometric characteristics alongside water absorption metrics as part of comprehensive material assessment.

Experimental Setup for Water Absorption

Outlines experimental procedures involving placing blocks at specific angles to ensure accurate moisture measurement without surface interference.

Details steps taken after 24 hours regarding moisture retention assessments and subsequent evaluations necessary for understanding material properties.

Final Observations on Material Properties

Concludes with observations about maintaining consistent environmental conditions during testing phases to ensure reliable results.

Discusses using controlled environments (like aquariums with screens), highlighting meticulous methods employed in measuring initial water absorption accurately.

Water Absorption in Ceramic Blocks

Initial Measurements and Observations

The dry mass of Block 2 is recorded at 12,650 grams with a temperature of 2650°C. A countdown to the next measurement begins.

Silas measures time for a 60-second interval while discussing an equation that involves mass differences and area calculations related to water absorption.

Dimensions of two blocks are provided: one measuring 9 cm in width and 23.5 cm in length, the other at 18.9 cm by 23.3 cm, leading to calculated areas of approximately 211.5 cm² and 207.4 cm² respectively.

Mass Calculations

Variations in mass are noted, with specific values for Block 2 being discussed (e.g., initial masses around 2,686 g).

The average water absorption rate is calculated as approximately 15.7 grams per minute over a surface area of about 93.75 cm².

Water Absorption Parameters

If the initial water absorption exceeds 30 grams, blocks must be pre-soaked before installation for optimal performance; otherwise, they can be installed immediately if below this threshold.

The importance of initial water absorption is emphasized as it significantly affects adhesion and performance during installation.

Testing Procedures

A limit of initial water absorption set at around 30 grams is established based on previous measurements; exceeding this requires additional preparation steps.

The discussion highlights how values obtained (15.7 g/min vs. the critical threshold of >30 g/min) influence whether blocks need pre-soaking.

Final Steps in Measurement

Next steps involve determining total water absorption after soaking blocks for a specified period; previously measured dry masses will be used for these calculations.

After soaking for a full day, further analysis will take place to assess saturation levels within the ceramic blocks.

This structured summary captures key insights from the transcript regarding the testing and evaluation process related to water absorption in ceramic materials while providing timestamps for easy reference back to specific parts of the video content.

Water Absorption and Mechanical Resistance in Ceramics

Water Absorption Calculations

The calculation for water absorption is demonstrated: 12 - 1984 - 2608/2668 , resulting in approximately 11.8% absorption.

A second calculation yields a similar result, with the average absorption being around 11.9%, which falls within acceptable limits.

Acceptable Limits for Water Absorption

The acceptable range for water absorption is between 8% and 22%. This ensures that the material can adequately bond with mortar without excessive porosity or moisture retention.

It’s emphasized that blocks must have sufficient surface characteristics to allow proper adhesion of mortars, highlighting the importance of physical properties.

Importance of Porosity Limits

If the water absorption exceeds 22%, it may lead to issues where too much moisture is drawn from the mortar, compromising its integrity.

Conversely, if absorption is below 8%, it indicates insufficient bonding capability with mortars, leading to potential structural failures.

Evaluating Ceramic Block Performance

The average calculated value of water absorption (11.9%) meets standards set by regulations, confirming suitability for use in construction.

Discussion shifts towards mechanical resistance; ceramic blocks are evaluated against a standard resistance threshold of at least 1.5 MPa.

Practical Testing Procedures

Practical tests will be conducted on blocks with horizontal holes to ensure they meet mechanical strength requirements before approval.

A leveling process using mortar ensures that all test samples are flat and parallel, crucial for accurate testing results.

Final Steps in Testing Process

After preparation, samples will undergo stress testing to determine their load-bearing capacity and overall durability under pressure.

The final load capacity recorded was approximately 53,300 N across a specified area, indicating strong performance metrics for the tested ceramic blocks.

Analysis of Block Resistance and Structural Integrity

Overview of Block Testing

The discussion begins with a calculation involving 53,300 neutrons divided by 20, resulting in a resistance value of approximately 2.52 Mega Pascal.

Observations are made regarding the surface condition of the blocks, noting that one block appeared to be loose but still supported significant weight.

Graphical Representation and Load Testing

A focus shifts to generating a graph that illustrates the load testing results for the blocks, allowing for better visualization of data.

A new block is introduced with a recorded load of 54,900 units; dimensions are discussed alongside its calculated resistance value.

Compliance with Standards

The importance of adhering to normative standards is emphasized, particularly regarding compressive strength which should be greater than or equal to 1.5 Mega Pascal.

Acceptance criteria for block lots are outlined: only two out of thirteen blocks can fail to meet the required compressive strength without disqualifying the entire lot.

Practical Application and Conclusions

The session concludes with practical observations on mechanical resistance tests conducted under saturated conditions, highlighting critical factors affecting performance.

It is reiterated that mechanical resistance is crucial for structural integrity in applications such as wall support systems.

Acknowledgments and Future Sessions

Gratitude is expressed towards students and technical staff who contributed to the practical session's success.

Special thanks are given to faculty members who facilitated access to facilities for conducting these practical lessons.

This structured summary encapsulates key insights from the transcript while providing timestamps for easy reference.