Performance Engineered Mixtures Program What A Contractor Needs to Know About the New AASHTO Provisional Guidelines and Suite of Tests Dr. Peter Taylor, PE (IL) 1 What is it? • A program to  Understand what makes concrete “good”  Specify the critical properties and test for them  Prepare the mixtures to meet those specifications 2 Step 1 • A better specification  Require the things that matter Transport properties (everywhere) Aggregate stability (everywhere) Strength (everywhere) Cold weather resistance (cold locations) Shrinkage (dry locations) Workability (everywhere) 3 Transport Properties/Permeability (6.6) Mixture Selection Section Property Specified Test Specifed Value Acceptance Special Notes Qualification Details 6.6 Transport Properties Water to Cement 6.6.1.1 0.45 ~ Yes Yes Ratio AASHTO T 318 Other criteria 6.6.1.2 RCPT Value AASHTO T 277 2000 ~ Yes Yes could be selected * Note this is currently based Choose on saturated Only One Formation AASHTO xx or curing and an 6.6.1.3 500 ~ Yes through ρ Factor/Resistivity AASHTO yy adjustment is needed to match with AASHTO Spec Ionic Penetration, F AASHTO xx or 25 mm at 6.6.2.1 Yes, F through ρ Factor AASHTO yy 30 year Aggregate Stability (6.7) Specifed Mixture Selection Special Section Property Specified Test Acceptance Value Qualification Details Notes 6.7 Aggregate Stability AASHTO T 161, ASTM 6.7.1 D Cracking ~ ~ Yes No C 1646/666 Alkali Aggregate 6.7.2 AASHTO PP 65 ~ ~ Yes No Reactivity Concrete Strength (6.3) Mixture Selection Special Section Property Specified Test Specifed Value Acceptance Qualification Details Notes 6.3 Concrete Strength 4.1 600 6.3.1 Flexural Strength AASHTO T 97 Yes Yes MPa psi Choose either or both Compressive 24 3500 6.3.2 AASHTO T 22 Yes Yes Strength MPa psi Hardened Cement Paste Freeze-Thaw Durability (6.5) Mixture Section Property Specified Test Specified Value Acceptance Selection Details Special Notes Qualification 6.5 Durability of Hydrated Cement Paste for Freeze-Thaw Durability Choose Either 6.5.1.1 Water to Cement Ratio AASHTO T 318 0.45 ~ Yes Yes 6.5.1.1 or 6.5.2.1 6.5.1.2 Fresh Air Content AASHTO T 152, T196, TP 118 5 to 8 % Yes Yes Choose ≥ 4% Air; %, 6.5.1.3 Fresh Air Content/SAM AASHTO T 152, T196, TP 118 Yes Yes only one SAM ≤ 0.2 psi Variation controlled with mixture proportion 6.5.2.1 Time of Critical Saturation "Bucket Test" Specification 30 Years Yes No Note 1 Note 2 observation or F Factor and Porosity Measures Are calcium or 6.5.3.1 Deicing Salt Damage ~ 35% SCM Yes Yes magnesium chloride used Are calcium or magnesium chloride 6.5.3.2 Deicing Salt Damage ~ ~ ~ Yes Yes Choose one used, needs a use of specified sealers Are calcium or 6.5.4.1 Calcium Oxychloride Limit Test sent to AASHTO < 0.15g CaOXY/g paste Yes No magnesium chloride used Note 1: Choose Either 6.5.1.1 or 6.5.2.1 Note 2: Choose either 6.5.1.2, 6.5.1.3, or 6.5.2.1 Reducing Unwanted Cracking Due to Shrinkage (6.4) Mixture Selection Section Property Specified Test Specifed Value Acceptance Special Notes Qualification Details 6.4 Reducing Unwanted Cracking Due to Shrinkage 6.4.1.1 Volume of Paste 25% Yes No Unrestrained Volume at 28 6.4.1.2 ASTM C157 420 µε Yes No Change day Unrestrained Volume 360, 420, at 91 6.4.2.1 ASTM C157 Yes No Change 480 µε days AASHTO T at 180 Choose 6.4.2.2 Restrained Shrinkage crack free Yes No 334 days only one AASHTO T 6.4.2.3 Restrained Shrinkage σ< 60% f'r at 7 days Yes No ??? as 6.4.2.4 Probability of Cracking ~ 5, 20, 50% Yes No specified Workability (6.8) Mixture Selection Special Section Property Specified Test Specifed Value Acceptance Qualification Details Notes 6.8 Workability <6.25 mm, < 30% 6.8.1 Box Test ~ Yes No Surf. Void Modified V-Kelly 15-30 mm per root 6.8.2 ~ Yes No Test seconds Step 2 • Better test methods (for those critical properties)  VKelly  Box  Resistivity / Formation factor  Sorptivity  Dual ring  SAM 10