粗骨料概述建筑材料与检测技术.pptx

粗骨料概述浙江同济科技职业学院主讲人：厉莎建筑材料与检测技术

教学目标1粗骨料的概念2TheconceptofcoarseaggregateTeachinggoals粗骨料的类别3Theclassificationofcoarseaggregate目录

1.教学目标Teachinggoals工作回顾教学目标12熟悉粗骨料的概念。Familiarwiththeconceptofcoarseaggregate.掌握粗骨料的分类。Mastertheclassificationofcoarseaggregate.Teachinggoals

2粗骨料的概念Theconceptofthecoarseaggregates

2粗骨料的概念Theconceptofthecoarseaggregate普通混凝土常用的粗骨料分卵石和碎石两类。卵石是由自然风化、水流搬运和分选、堆积形成的，粒径大于4.75mm的岩石颗粒。按其产源不同可分为河卵石、海卵石、山卵石等。碎石是天然岩石或卵石经机械破碎、筛分制成的，粒径大于4.75mm的岩石颗粒。pebblecrushedstone2.1卵石和碎石pebbleandgravelThecoarseaggregatecommonlyusedforordinaryconcreteisdividedintopebbleandgravel.Pebblesareformedbynaturalweathering,watertransport,sortingandaccumulation,andtheparticlesizeislargerthan4.75mm.Itcanbedividedintoriverpebble,seapebbleandmountainpebbleaccordingtodifferentproductionsources.Crushedstoneismadeofnaturalrockorpebblethroughmechanicalcrushingandscreening,andtheparticlesizeislargerthan4.75mm.

2粗骨料的概念Theconceptofthecoarseaggregate天然的卵石表面光滑、多为球形，与水泥的粘接力较差，用卵石拌制的混凝土拌和物和易性好，但混凝土硬化后强度较低；且卵石堆积的空隙率和表面积小，拌制混凝土时水泥浆用量较少。碎石表面粗糙、多棱角，与水泥有很好的粘接，用碎石拌制的混凝土拌和物流动性较差，但混凝土硬化后强度较高。2.2卵石、碎石拌制混凝土ConcretemixedwithpebbleandgravelNaturalpebbleshavesmoothsurface,mostlyspherical,andpooradhesionwithcement.Theconcretemixturemixedwithpebbleshasgoodworkability,butthestrengthofconcreteafterhardeningislow;Moreover,thevoidsandsurfaceareaofpebblesaresmall,andthecementslurryisusedlesswhenmixingconcrete.Thesurfaceofcrushedstoneisroughandangular,andithasgoodadhesionwithcement.Theconcretemixedwithcrushedstonehaspoorfluidity,butthestrengthofconcreteafterhardeningishigh.

3粗骨料的类别Classificationofcoarseaggregate根据GB/T14685－2022《建筑用卵石、碎石》，按卵石、碎石的技术要求从高到底，可将其分为I类、II类、III类三种类别。I类宜用于高强混凝土（≥C60）II类宜用于中强（C30～C60）的混凝土和抗冻、抗渗及其它要求的混凝土。III类宜用于低强（＜C30）的混凝土和建筑砂浆。Accordingto