Basics of Joints Improving Performance

Transcription

1 Basics of Joints Improving Performance IHRB Project TR-697 Guide to the Prevention and Restoration of Early Joint Deterioration in Concrete Pavements ICPA Workshop February 1, 2017 Iowa Needs Concrete Steven L. Tritsch, P.E.

2 IHRB TR-697 2

3 Credits Authors Jason Weiss, Ph.D., Oregon State University M. Tyler Ley, Ph.D., P.E., Oklahoma State University Larry Sutter, Ph.D., Michigan Tech University Dale Harrington, P.E., Snyder and Associates, Inc. Jerod Gross, P.E., Snyder and Associates, Inc. Steven L. Tritsch, P.E., CP Tech Center Editor Marcia Brink, CP Tech Center 3

4 Technical Advisory Committee Matthew Cox, P.E., City of Council Bluffs Todd Hanson, P.E., Iowa Department of Transportation Sarah Okerlund, P.E., City of Ankeny Gordon Smith, P.E., Iowa Concrete Paving Association Dr. Peter Taylor, P.E., National Concrete Pavement Technology Center Jacob Thorius, P.E., Washington County Bob Younie, P.E., Iowa Department of Transportation

5 Particulars Total pages in the document pages of text 29 figures 6 tables 84 references Links to appropriate specifications/templates 5 page tech brief 5

6 Contents Executive Summary 1. History of Joint Design and Performance in Iowa 2. Types and Mechanisms of Joint Deterioration 3. Preventing Joint Deterioration in New Pavements 4. Maintenance Activities to Reduce Joint Deterioration Risk 5. Treatment of Pavements with Joint Deterioration 6. Specification Guidelines References 6

7 A Touch of Iowa History First Pavement built in 1904 in Le Mars Two pavements still in service today built in 1909 and Original slabs were 18 wide, 20 starting in 1935, 22 in 1949, and 24 in From 1920 to 1925 no joints were placed longitudinal joint installed from 1925 to beginning in 1930 transverse joints were placed at 100 intervals and went through several changes to the standard 20 today. Eddyville Cemetery Road

8 A Touch of Iowa History Early pavements were built with gravels until the late 30 s when limestone became the predominant material for coarse aggregate. D-cracking was researched extensively and poor aggregate sources identified. In 1952, air entrainment was required to mitigate freeze-thaw damage. Early 1990 s saw the advent of early joint deterioration leading to more research into vibration, air content, saturation levels, and expansion of paste via calcium oxychloride. Moscow Road

9 Types and Mechanisms of Joint Deterioration Saturated Freeze-thaw Damage Volume of pores Measure mass change from oven dry to vacuum saturated Degree of saturation Compare mass of sample with oven dry and saturated masses Sorption / Saturation ASTM C 1585 (modified) Jason Weiss 9

10 Types and Mechanisms of Joint Deterioration Calcium Oxychloride Formation, Expansion, and Damage Chemical Reaction Calcium chloride and calcium hydroxide forms calcium oxychloride cracking due to volume change Mitigate Use SCMs Reduces calcium hydroxide Use low w/c ratios to reduce fluid transport Proper entrained air-void system

11 Preventing Joint Deterioration in New Pavements Soil, Subgrade, and Base systems Stabilized subgrade Granular subbase Drainage of pavement system Concrete Mixture Recommendations Low water-cement ratio Supplementary cementitious materials Well-graded aggregates Air-void system

12 Preventing Joint Deterioration in New Pavements Construction Practices Curing Ensure adequate coverage and application rate Sawing joints Sawing window and proper depth Sealing joints If seal, have to maintain the seal Consider drainable base Surface Sealers If use, consider high solids content Research is ongoing

13 Maintenance Activities to Reduce Joint Deterioration Risk Routine Maintenance Joint cleaning and sealing Surface sealers Drainage Winter Maintenance Deicing/anti-icing chemicals IA averaged 19,463,924 gallons of brine application in the last two years - #2 state was CO 13,524,500 Calcium chloride and magnesium chloride are more detrimental to cement paste than sodium chloride Do not expose concrete to salt for at least 30 days after placement

14 How Much is Enough Freezing Point (ºF) Sodium Chloride Magnesium Chloride Calcium Chloride Calcium Magnesium Acetate Concentration (wt%) Salt Concentration (wt%) Freezing Point (F) Sodium Chloride Magnesium Chloride Calcium Chloride Calcium Magnesium Acetate

15 Treatment of Pavements with Joint Deterioration Selection and timing of repairs Figure 5-1 recommend decision matrix Joint condition with appropriate action Address underlying causes Water access Salt type and application rates Surface (penetrating) sealers Partial-depth repairs Top half of pavement Timing further investigate if slab <7 years

16 Treatment of Pavements with Joint Deterioration Full-depth repairs Typically when spall is >4 If large quantity, may consider full panel replacement or unbonded concrete overlay Unbonded concrete overlay of concrete Economy of scale condition of exitsting pavement Separation layer nonwoven geotextile fabric or thin HMA interlayer Recycling concrete pavements Typically used as base material in Iowa

17 Specification Guidelines Definitions Concrete mixes Iowa DOT Durability Mixes QM-C Developmental Specification DS Municipality Durability Mixes C-SUD CV-SUD C-SUD-C33 (higher fly ash content)

18 Specification Guidelines Partial-depth repairs Types Materials Proprietary mixes Joint boards/compressible inserts Standard Road Plan PR-107 Full-depth repairs Types Materials Method of measurement and payment Standard Road Plan PR-103

19 Tech Transfer Summary 19

20 In Short Low w/cm ratio consider 0.4 target Adequate entrained air 5% to 8% w/5% min in place SCMs 20-25% class F fly ash 30-35% class C fly ash Combination 20% slag and 20% C fly ash Well graded aggregates Use chemicals appropriately Salts Penetrating sealers 20

21 Thank you for your time cptechcenter.org 21