This standard outlines the criteria for burnt clay fly ash bricks, detailing their categorization, sizes, physical attributes, and quality benchmarks. It is relevant for those manufacturing and utilizing bricks with compressive strength below 30 N/mm², encouraging eco-friendly building practices through the use of fly ash and soil conservation.
Overview
This standard outlines the criteria for burnt clay fly ash bricks, detailing their categorization, sizes, physical attributes, and quality benchmarks. It is relevant for those manufacturing and utilizing bricks with compressive strength below 30 N/mm², encouraging eco-friendly building practices through the use of fly ash and soil conservation.
Audience
Contents
Structure
This section defines the requirements for burnt clay fly ash bricks, including their dimensions, shapes, and testing procedures, with results rounded in accordance with IS 2:1960. It references relevant standards such as IS 2248:1981 and specifies both modular and non-modular brick sizes. Non-modular bricks have sizes like 230 mm length, 110 mm width, and heights of 70 mm or 30 mm, with frog details illustrated in figures.
Lists other Indian Standards applicable to burnt clay fly ash bricks including IS 1077, IS 2117, IS 2180, IS 2248, IS 3495 (Parts 1-3), IS 3812, and IS 5454. It emphasizes the rounding off of test results per IS 2:1960 and presents the standard brick dimensions for non-modular bricks as part of compliance.
Clarifies that definitions used conform to IS 2248:1981. It also mentions the rounding off rules for test results as per IS 2:1960, maintaining the same significant digits as specified. Details on permissible non-modular brick dimensions are provided, along with references for additional relevant standards.
Describes brick categorization based on average compressive strength, ranging from Class 3.5 (≥ 3.5 N/mm²) up to Class 30 (≥ 30 N/mm²). It specifies rounding off test values per IS 2:1960 and outlines permissible fly ash content percentages depending on the class.
Outlines the quality requirements including precise rounding off of test outcomes, classification per compressive strength classes, and dimensional tolerances for modular and non-modular bricks. It provides nominal dimensions with acceptable variation ranges to ensure consistency.
Details the standard modular brick sizes (190x90x90 mm and 190x90x40 mm) and non-modular sizes (230x110x70 mm and 230x110x30 mm). It mandates smooth rectangular surfaces with sharp edges and uniformity in shape and color, with test results rounded according to IS 2:1960.
Specifies dimensional tolerance limits measured on 20 bricks arranged in a line, including length, width, and height ranges for both modular and non-modular bricks. Measurement procedures require removal of surface defects prior to assessment. Frog dimensions for non-modular bricks are also defined.
Explains sampling methods based on IS 5454:1978 for selecting representative bricks for testing. Acceptance or rejection of lots follows defined criteria including sample size and acceptance numbers. Efflorescence limits are set according to IS 3495 (Part 3):1992, with maximum allowable ratings based on brick class.
Mandates that each brick bears the manufacturer's identification mark or initials, usually stamped within the frog. Use of the Standard Mark is optional to indicate conformity. Marking aids traceability and quality assurance under BIS supervision, with rounding of test data as per IS 2:1960.
Frequently Asked
Standard modular bricks have dimensions of 190 mm length, 90 mm width, and either 90 mm or 40 mm in height. Non-modular bricks are measured in batches of 20, with total length 4600 ± 80 mm, total width 2200 ± 40 mm, and total height either 1400 ± 40 mm for 70 mm thick bricks or 600 ± 40 mm for 30 mm thick bricks. These sizes maintain uniformity and ease of use in construction.
Bricks are classified by their minimum average compressive strength ranging from Class 3.5 (≥ 3.5 N/mm²) up to Class 30 (≥ 30 N/mm²). Each class corresponds to a specific strength value in kgf/cm², starting at 35 kgf/cm² for Class 3.5 and going up to 300 kgf/cm² for Class 30. This classification assists in selecting bricks suitable for various structural demands.
Water absorption should not exceed 20% after 24 hours of immersion in cold water, as per IS 3495 (Part 2):1992. Efflorescence levels must be rated 'moderate' or less for bricks up to Class 12.5, and 'slight' or less for bricks above Class 12.5, in accordance with IS 3495 (Part 3):1992. These limits ensure durability and aesthetic quality.
Sampling follows IS 5454:1978, selecting representative bricks randomly from a lot. At least 20 bricks are tested for dimensions and physical properties. Measurement involves arranging bricks in a row and assessing overall dimensions with allowances for tolerances. Efflorescence tests and compressive strength assessments are carried out as per relevant IS codes. Results are rounded per IS 2:1960, and acceptance criteria determine lot approval.
Burnt clay fly ash bricks are produced from suitable soils blended with fly ash conforming to Grade 1 or Grade 2 as specified in IS 3812:1981. The manufacturing process should ensure uniform firing, absence of defects such as cracks or black cores, and adherence to specified frog dimensions. Usage of these fly ash grades guarantees brick durability and compliance with strength classifications.
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