3 Materials 1 2 3 4 5 6 7 8 9 10 CIRIA C683 63 3 Materials CHAPTER 3 CONTENTS 3.1 Introduction. 71 3.1.1 Materials considerations for concept stage. 72 3.1.1.1 Scale of project . 72 3.1.1.2 Planning and timescales . 73 3.1.1.3 Top sizes of armour . 73 3.1.1.4 Rock source and procurement options . 73 3.1.1.5 Holistic considerations . 74 3.1.1.6 Cost of project. 76 3.1.1.7 Towards preliminary design. 76 3.1.2 Important design functions and properties of materials. 79 3.1.2.1 Functions of materials in the structure . 79 3.1.2.2 Material properties . 81 3.1.3 Durability considerations . 82 3.1.3.1 Mitigation strategies for low-durability scenarios of rock armour . 83 3.1.3.2 Durability considerations for material other than armourstone. 83 3.1.4 Standards for armourstone. 84 3.2 Quarried rock – overview of properties and functions. 86 3.2.1 Introduction to quarried rock . 86 3.2.2 Introduction to engineering geology . 86 3.2.3 Quarry evaluation principles . 91 3.2.4 Properties and functions – general. 94 3.3 Quarried rock – intrinsic properties . 95 3.3.1 Aesthetic properties of armourstone . 95 3.3.2 Petrographic properties . 95 3.3.3 Mass density, porosity and water absorption . 95 3.3.3.1 Phase relations . 95 3.3.3.2 Density definitions . 96 3.3.3.3 Degree of saturation in stability calculations . 97 3.3.3.4 Density variation in a quarry . 98 3.3.3.5 Mass density as a durability indicator . 98 3.3.3.6 Mass density as a design parameter. 98 3.3.4 Resistance to breakage and armourstone integrity . 98 3.3.5 Armourstone resistance to wear . 101 3.4 Quarried rock – production-induced properties . 101 3.4.1 Shape . 101 3.4.1.1 Length-to-thickness ratio (LT) . 102 3.4.1.2 Blockiness (BLc) . 102 3.4.1.3 Cubicity . 103 3.4.1.4 Roundness. 103 3.4.1.5 Proportion of crushed or broken surfaces. 104 3.4.1.6 Shape for specification purposes . 104 64 CIRIA C683 Contents 3.4.1.7 Shape for design and dimensioning purposes . 104 1 3.4.1.8 Factors controlling armourstone shape during quarry production . 106 3.4.2 Dimensions of pieces of armourstone. 107 3.4.3 Size and mass distribution of armourstone gradings. 107 3.4.3.1 Grading width and common terminology . 108 3.4.3.2 EN 13383 system for standardisation of gradings. 109 2 3.4.3.3 Rosin-Rammler curves for mass and size distributions and idealised gradings. 112 3.4.3.4 Graphical illustration of EN 13383 standard grading curves . 114 3.4.3.5 Fragments and effective mean mass, Mem . 114 3.4.3.6 Requirements and compliance of EN 13383 standard gradings . 114 3 3.4.3.7 Additional information on EN 13383 standard gradings . 115 3.4.3.8 Relationship between Mem and M50 , and grading widths including practical experience . 116 3.4.3.9 Non-standard gradings. 117 3.4.4 Core materials . 119 4 3.4.4.1 Core materials terminology . 120 3.4.4.2 Core materials in a design context. 120 3.4.4.3 Calculating the porosity of bulk-placed materials . 121 3.5 Quarried rock – construction-induced properties . 123 3.5.1 Layer thickness and porosity of individually placed armourstone . 123 5 3.5.1.1 Importance of layer thickness coefficient kt and porosity nv. 125 3.5.2 Effect of rock density on design parameters . 129 3.6 Rock quality, durability and service-life prediction . 131 3.6.1 Introduction . 131 6 3.6.2 Durability and degradation. 132 3.6.3 Procedure for source evaluation of rock quality . 133 3.6.4 Principles of degradation modelling . 139 3.6.5 In-service degradation models for general wear of armourstone. 140 3.6.5.1 Micro-Deval (MDE) method. 141 7 3.6.5.2 Armourstone quality designation (AQD) method . 142 3.6.5.3 Comparison between MDE and AQD methods. 145 3.6.6 Modelling degradation due to breakages. 147 3.6.6.1 Effects of minor breakages and major breakage . 147 3.6.6.2 Quantitative effect of breakages on armourstone grading using 8 statistical model. 150 3.6.6.3 Prediction of the effect of major breakages using a dedicated degradation model specific for breakage. 151 3.6.7 Summary of recommendations for degradation modelling . 154 9 3.7 Preparing the armourstone specification . 155 3.7.1 EU context. 156 3.7.2 Non-EU context . 160 3.8 Testing and measuring . 160 3.8.1 Sampling . 161 10 CIRIA C683 65 3 Materials 3.8.2 Testing of physical properties . 164 3.8.2.1 Petrography . 164 3.8.2.2 Aesthetic properties . 164 3.8.2.3 Rock density, water absorption and porosity. 164 3.8.3 Testing properties of individual pieces of armourstone . 165 3.8.3.1 Shape. 165 3.8.3.2 Mass and size. 165 3.8.4 Testing geometrical properties of armourstone as a granular material . 167 3.8.4.1 Shape. 167 3.8.4.2 Mass distribution. 168 3.8.5 Mechanical properties. 171 3.8.5.1 Resistance to breakage . 171 3.8.5.2 Armourstone integrity . 172 3.8.6 Durability and accelerated weathering tests. ..