CM 3400 Test II Study Sheet

CM 3400 Test II Study Sheet - CM 3400 Test II Study Sheet...

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CM 3400 Test II Study Sheet CONCRETE/CEMENT PCC = cement + aggregate + water + admixtures Concrete Ingredients: - cement - water - aggregate (60-75% by volume of PCC) - admixtures - waste/recyclable materials Portland cement develops adhesive and cohesive properties Raw Materials - Calcium (CaO) - Silica (SiO2) - Alumina (Al2O3) Major Chemical Components - Tricalcium Silicate C3S o Harents rapidly, reposnible for initial setting and early strength - Dicalcium Silicate, C2S o Hardens slowly with less heat, responsible for late strength (after 7days) - Tricalcium Aluminate, C3A o Slight early strength, low heat of hydration, may contribute to sulfate attack - Tetracalcium Aluminoferrite, C4AF o Reduces clinkering temp, does not contribute to strength Concrete Types - Type I: General Purpose, normal hydration - Type II: Moderate Sulfate Resistance, Less heat of hydration - Type III: High early strength, high HoH - Type IV: Low heat of hydration - Type V: High sulfate resistance , Soundness is the ability of a hardened paste to retain its volume after setting Setting time describes the stiffening of the cement paste - False set is the significant loss of plasticity without the evolution of heat (can be overcome with mixing) - Flash set is significant loss of plasticity with evolution of heat, cannot be overcome Fineness of cement also affects the rate of heat developed but not the total amount of heat liberated Compressive strength of cement is the most comment measure of strength
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Water: - hydrates cement - provides workability - allows for ingress of deteriorating substances - Shouldn’t affect 7-day mortar cube strength - F’c questionable water > 90% F’c distilled water Carbonates and bicarbonates in water may cause alkali-aggregate reaction, and or affect setting time and strength Sulfates may cause expansion – react with C3A Salts may discolor concrete or cause strength loss Permeability is a measurement of flow thru a solid substance Inverse relationship between porosity and strength Aggregates: - 60-75% by volume, 70-85% by weight - Act as inert skeleton - Reduces amount of cement needed - Provides stability - Can be: o Natural o Man made o Recycled material o Municipal waste - Soundness and Durability o Freeze-thaw o Wetting and drying - Need to know nominal maximum aggregate size (SG) and absorption - FM=fineness modulus = Sum (100-%passing)/100 - Surface Moisture = (Damp – SSD/ SSD)x100 - Absorption capacity = (SSDweight – oven dry weight/oven dry weight)x100 - Effective Absorbtion = (SSD weight – air dry weight/air dry weight)x100
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CM 3400 Test II Study Sheet - CM 3400 Test II Study Sheet...

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