Introduction to Masonry Materials and Assemblages

Transcription

1 2:15 PM 4:15 PM Bennett Banting Introduction to Masonry Materials and Assemblages Lecture Outline 1. Overview (5) 2. Masonry Materials a) Concrete Block (20) b) Mortar (15) c) Grout (15) 3. Masonry Assemblages a) Axial Compression (35) b) Flexure (20) c) Shear (5) 4. Content Review (5) 2018 Canada Masonry Design Centre 1

2 Masonry Materials Modern Masonry Construction in Canada Focus of this course Part 4 (NBCC/OBC Objective-Based Design & Limit States) 2004 Editions of Masonry Standards (elearning for 2014 update) What is masonry? 1. Complete Buildings Loadbearing structure, seismic force resisting system, walls, beams, columns, non-loadbearing partition walls, exterior veneers, hardscaping 2. Specific or Specialty Components of a Building Firewalls, Acoustic Walls, Infills, Veneers, Partitions, Fire Place, Feature Wall, Thermal Mass Wall 3. Historic Restoration Preserve, maintain, restore, enhance What isn t Covered 1. Precast concrete systems It may look like brick but it has nothing to do with masonry Not to be confused with pre-assembled post-tensioned masonry panels 2. Siding or Stucco Many materials mimic a masonry look but have no connection to the product or industry 3. Sub-standard materials and unskilled tradespersons An unfortunate by-product of all construction industries 2018 Canada Masonry Design Centre 2

3 Modern Masonry Veneer Wall Also sometimes referred to as a Cavity Wall Exterior Veneer Typically Non-Loadbearing (Clay Brick, Stone, Concrete Brick or Block) Air Space Air-Vapour Barrier Through-Wall Flashing Insulation Ties and Shelf Angles Back-up Wall Loadbearing Concrete Block Loadbearing Back-up Wall Concrete Block Reinforced Grouted Partially or Fully 2018 Canada Masonry Design Centre 3

4 Concrete Block (Pages ) (CSA A165) Concrete Block Cinder Block (when coal cinders were used years ago) Loadbearing and Non-Loadbearing Applications Architectural and Structural Fire and Sound Ratings Partitions, Wind Walls, Shear Walls, Foundation Walls 2018 Canada Masonry Design Centre 4

5 Manufacturing Hopper takes a very dry concrete mix (zero slump): cement, fine aggregate, water, additives. 2. Vibration and pressure is applied as molds are filled with concrete mix. 3. Blocks leave machine in desired shape but very weak and are typically steam cured. 3 Manufacturing (Industry Average Typical Block Mix) CCMPA Environmental Product Declaration kg/m 3 kg/m 3 Normal Weight Light Weight Portland Cement Blended Cement Slag Cement (GGBFS) Fly Ash Crushed Coarse Aggregate Natural Coarse Aggregate Crushed Fine Aggregate Natural Fine Aggregate Expanded Slag 0 1,207 Pumice Silica Flour Water Reducing Admixture (plasticizer) Water Repellant/Effloresence Control Admixture Air Entraining Admixture Batch Water Total kg/m 3 2,250 1, Canada Masonry Design Centre 5

6 Terminology 1 1. Cell 2. Face Shell (Bed Joint) 3. Web 2 3 Terminology 1. Ears (Head Joint) 2. Frog 3. Flare Canada Masonry Design Centre 6

7 Geometry Modular Dimensions 1. Length 2. Width (Thickness) 3. Height Actual vs. Nominal Dimensions Nominal Planning, layout & design (accounts for mortar joint) Actual Modular, less the mortar joint 2018 Canada Masonry Design Centre 7

8 Modular Masonry Construction Fewer cuts Better aesthetics Improved integrity and structural performance Quicker construction Less wasted material and time Metric Modular Brick and Concrete Block 2018 Canada Masonry Design Centre 8

9 Concrete Block Dimensions Concrete Block Thickness Canada Masonry Design Centre 9

10 Concrete Block Thickness cm Concrete Block Vertical Rebar? 2018 Canada Masonry Design Centre 10

11 Block Specifications 4-Facet System 1 - Solid Content Hollow <75% Solid Semi-Solid >75% Solid Full Solid 2018 Canada Masonry Design Centre 11

12 2 Minimum Compressive Strength Specified Strength Block Strength Design Strength 15 MPa, 20 MPa, 25 MPa, 30 MPa, 40 MPa (2004) Canada Masonry Design Centre 12

13 Engineered Masonry Design Course Friday April 13, Concrete Type Density Lightweight Block (Fire, Production) Normal Weight Block (Exposed, High Strength) Absorption 4 Moisture Content Specified Moisture Content of Block Mitigate Shrinkage 2018 Canada Masonry Design Centre 13

14 Special Unit Shapes Stack Pattern Bond Pattern 50% Running Bond w/ Ashler Units 50% Running Bond 2018 Canada Masonry Design Centre 14

15 Additional Specifications Sound (STC and ASTC) Acoustic Engineer Fire Engineering Design (This Course) Typically 20 cm up to 30 cm Start with 15 MPa, but 20 MPa to 30 MPa likely Normal Weight Hollow Units 2018 Canada Masonry Design Centre 15

16 Mortar (Pages ) (CSA A179) Mortar Tolerances Strength Durability 2018 Canada Masonry Design Centre 16

17 The Mortar Joint 10 mm ± 3 mm 6 20 mm First Course Only Concrete Block Width ± 2 mm Height + 2, - 3 mm Length ± 3 mm Concave, Struck, Raked Composition Portland Cement & Hydrated Lime Masonry Cement Mortar Cement Aggregate (sand) Water 2018 Canada Masonry Design Centre 17

18 Properties Plastic properties (e.g., workability and water retentivity) determine construction suitability Hardened properties (e.g., compressive strength, bond strength, durability, and deformability) determine the performance of the finished masonry Properties vary with mortar type no single mortar type is best for all purposes it is important that the mortar type selected for a particular application Types MaSoN work M, S, N, O, K Historic applications ONLY New Construction: Type S Loadbearing, Exterior Below Grade Type N Low Strength Walls, Exterior Above Grade 2018 Canada Masonry Design Centre 18

19 Specification Proportion Specification Jobsite Mixed Property Specification Pre-Blended, Off-Site Mix Proportion Spec 2018 Canada Masonry Design Centre 19

20 Proportion Spec Property Spec 2018 Canada Masonry Design Centre 20

21 Property Spec Grout (Pages ) (CSA A179) 2018 Canada Masonry Design Centre 21

22 Grout High Slump High w/c Small Aggregate Low Cylinder Strength Workable Composition Portland Cement Hydrated Lime Aggregate Water Grout Mortar, Concrete 2018 Canada Masonry Design Centre 22

23 Specifications Proportion Fine Coarse Property Proportion Spec 2018 Canada Masonry Design Centre 23

24 Property Spec Special Considerations for Grout Strength Requirements Water loss in unit Block Grout Cylinder Mortar Cube You cannot compare materials tests of different geometric properties Material testing is for quality assurance Assemblage testing tells you in-wall strnegth 2018 Canada Masonry Design Centre 24

25 Special Considerations for Grout Priority Fill Open Cells (Workable) Special Considerations Mortar as Grout Non-structural applications Bond and compaction issues Ready Mix Concrete Only plants that have masonry grout mixes Pea Gravel can be pumped Self-Consolidating Grout 2018 Canada Masonry Design Centre 25

26 Assemblages: Axial Compression (Pages ) (CSA S304 Annex D) Axial Compression Masonry Prisms Mini Walls Represent complex interaction and anisotropic behaviour Design Strength (f m ) is derived from assemblage tests, NOT material tests Theoretical prediction difficult Tables provided in S304 based on block (Irrespective of grout or mortar strength) 2018 Canada Masonry Design Centre 26

27 Failure of Masonry Prisms 2018 Canada Masonry Design Centre 27

28 c d b e Prism Configurations a f Prism Unit Grouting Bond Pattern Courses Height-to-Thickness Ratio a) 20cm Hollow Block No 50% Running 2 2 b) 20cm Hollow Block No 50% Running 5 5 c) 20cm Hollow Block Yes (x-section shown) 50% Running d) 30cm Hollow Block No 50% Running 5 5 e) 20cm Hollow Block No Stack Pattern 5 5 f) 90mm Clay Brick No Stack Pattern Unit Bonding 2018 Canada Masonry Design Centre 28

29 Specified Strength Scatter in Experimental Data Effect of Grout is NOT Additive Material Reduction factor ϕ m = 0.6 Recall Concrete ϕ c = 0.65 Recall Reinforcing Steel ϕ s = 0.85 Other Design Properties of Masonry E m = 850f m ε mu = Canada Masonry Design Centre 29

30 Type of Grout Grout Cylinder Block Strength Measured Specified Prism Strength Pre-Blend Coarse 19.0 MPa 9.1 MPa Grout (CSA A179) 17.9 MPa Special High- Strength SCG 69.9 MPa 12.3 MPa High Strength Grout Superposition not Possible Flexure (Pages ) 2018 Canada Masonry Design Centre 30

31 In-Plane vs. Out-of-Plane: Normal to Bed Joints In-Plane vs. Out-of-Plane: Parallel to Bed Joints 2018 Canada Masonry Design Centre 31

32 Flexural Compressive Strength (Normal to Bed Joints) Eccentric Prism Tests In-Plane and Out-of-Plane Simulate flexure Creates strain gradient M = P e e P e P Flexural Compressive Strength (Parallel to Bed Joints) Anisotropic (different properties along each axis) Concrete and steel are considered isotropic Wood and masonry are considered anisotropic Strength reduction factor χ Otherwise same compression block 2018 Canada Masonry Design Centre 32

33 Rectangular Stress Block Flexural Tensile Strength Tension Normal to the Bed Joints (Out-of-Plane but also In-Plane) 2018 Canada Masonry Design Centre 33

34 Flexural Tensile Strength Tension Parallel to the Bed Joint (Out-of-Plane) Flexural Tensile Strength 2018 Canada Masonry Design Centre 34

35 Shear (Pages ) Shear Strength of Mortar Joints 2018 Canada Masonry Design Centre 35

36 Diagonal Tensile Shear Content Review 2018 Canada Masonry Design Centre 36

37 Review Actual versus Nominal Dimensions Block Strength, Mortar Strength, Grout Strength and Masonry Strength Important properties for block, mortar and grout Masonry is anisotropic In-Plane vs. Out-of-Plane Normal to Bed Joints vs. Parallel to Bed Joints 2018 Canada Masonry Design Centre 37