Measurement Criteria: Soil Cement, FDR, & RCC Pavement Market 2018

Transcription

1 Measurement Criteria: Soil Cement, FDR, & RCC Pavement Market 2018 A survey of decision maker s attitudes & perceptions in the soil cement, fulldepth reclamation and roller compacted concrete pavements market. February 2018 Portland Cement Association 5420 Old Orchard Road Skokie, Illinois Fax The Portland Cement Association (PCA) and its members make no express or implied warranty with respect to this publication or any information contained herein. In particular, no warranty is made of merchantability or fitness for a particular purpose. PCA and its members disclaim any product liability (including without limitation any strict liability in tort) in connection with this publication or any information contained herein. Copyright 2018 by the Portland Cement Association. All rights reserved

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3 Table of Contents Introduction & Methodology... 1 Executive Summary... 2 Demographic Information... 3 Organization Type... 3 Type of Contact... 3 Types of Pavements Used... 4 Number of Paving Projects... 4 Level of Influence in Pavement Decisions... 5 Average Age of Pavement Types... 5 Subgrade Modification... 6 Awareness & Use... 6 Subgrade Modification Materials... 7 Likelihood to Recommend Subgrade Modification Materials... 8 Subgrade Modification Materials Rating Expected Outcomes of Subgrade Modification Bases Awareness & Use Base Material Rating Likelihood to Recommend Base Materials Sources of Information on Base Materials Flexible Pavement Reconstruction Recycling Methods Likelihood to Recommend Stabilizers Types of Stabilizers in FDR Projects Roller-Compacted Concrete (RCC) Pavements Types of Pavements Used Awareness & Use Likelihood to Recommend RCC Pavement Ratings Public vs. Private RCC Projects Fugitive Dust Concerns Future Trends... 24

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5 Measurement Criteria: Soil-Cement, FDR, & RCC Pavement Market 2018 PCA Market Intelligence surveyed decision makers in the pavement market to measure their attitudes and perceptions toward soil-cement, full-depth reclamation (FDR), roller-compacted concrete (RCC) pavements, and competing base and subbase materials. This research is part of ongoing effort to measure the effectiveness of promotions by tracking market share, attitudes and perceptions of decision makers and their awareness of various cement-based pavement systems. This survey is a follow-up to the original benchmark survey conducted in 1996 with subsequent studies executed in 2002 and Comparisons are made among the three prior surveys throughout this report in order to establish tracking and trend analysis. In the 2018 survey, two new questions were added to better understand: The level of influence of pavement professionals participating in the survey: Respondents were asked on a scale of 1 to 10, given their position, how much influence they have in pavement type selection. Concern of fugitive dust from the spreading of dry stabilizers: Respondents were asked how much of a concern fugitive dust from the spreading of dry stabilizers (e.g. lime, cement, fly ash) is vs. slurry placement in urban and rural settings. Several definitions were provided to respondents to prevent any misunderstanding. These definitions follow: Subgrade Stabilization: modification and improvement of native soils below the base course. Soil-Cement Bases: also called cement treated bases. This refers to the materials used for the principal structural layer below the surface course. Full-Depth Reclamation: process that pulverizes the existing asphalt surface and base and, in many cases, is mixed with a stabilizer like cement to produce a new pavement base. Methodology For the 2018 study, PCA partnered with Roads & Bridges Magazine to gain access to their subscriber list. A gift card incentive of $25 or donation to a charity of the same amount was provided to the first 300 respondents. The scope of most of the survey questions was limited to projects respondents had worked on over the past year. The survey was sent by to a tailored list of approximately 22,000 paving professionals on December 19, 2017 and again on January 16, 2018 after having removed addresses of those who had already responded. The survey contained 27 questions, including those on demographics. The survey garnered 346 usable responses which were analyzed for this report. February 2018 Page 1

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7 Executive Summary Subgrade Modification Awareness of subgrade modification has grown significantly since In 2018, 69% of respondents reported being either familiar or very familiar with it; only 7% of survey participants were not familiar with subgrade modification. In contrast, 32% of respondents to the 2005 survey were not familiar with subgrade modification. Similarly, a larger share of projects now require the use of subgrade modification. Respondents most frequently use and are most likely to recommend portland cement for subgrade modification. Cement was rated higher than lime for all decision making variables except initial cost, but lime s favorable position in initial cost has continued to erode in Bases A majority of respondents (57%) are either familiar of very family with cement stabilized bases. Only 8% of survey participants are not familiar with cement stabilized bases far less than the 2005 study which revealed 33% of respondents were not familiar with cement stabilized bases. Growth in the likelihood to recommend a cement stabilized base improved in tandem with the percent of projects using cement stabilized bases. The use of (now 17% of base material) and likelihood to recommend cement stabilized bases has increased in every study since PCA remains the most used source among respondents for information on cement stabilized bases. Flexible Pavement Reconstruction The most common recycling method when an asphalt pavement has failed is to tear it up and rebuild with new material, but full-depth reclamation has increased in popularity since prior surveys and now is the second most used option at 30% of projects. Cement is used as a stabilizer in approximately 30% of recycling projects, which has grown since the 1996 survey (19%) but has decreased slightly since the 2005 study (33%). The likelihood to recommend cement for recycling pavements grew to its highest recorded level in Roller-Compacted Concrete (RCC) Pavements Familiarity with RCC pavement systems increased dramatically in the 2018 survey with 92% of all respondents now familiar with RCC. In 2005, 45% of those surveyed were not familiar with RCC. Respondents are most likely to recommend RCC for heavy industrial/intermodal and commercial parking/storage applications. The spreading of fugitive dust from dry stabilizers is of much greater concern in urban areas with 71% of respondents indicating concern (prefer slurry placement) or major concern (only allow slurry placement) in urban projects. In rural areas, virtually the opposite is true with 68% of survey participants expressing minor or no concern with fugitive dust in rural settings. Future Trends Survey respondents expect growth over the next five years in cement-based pavement systems to a larger degree than the participants in the 2005 survey predicted. February 2018 Page 2

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9 Demographic Information Organization Type Of those surveyed, 21% currently work for a municipal or city agency, with another 21% working for a general civil engineering firm. Organization Type Municipal/City Agency 21% General Civil Engineering Firm 21% Contracting Company 18% County Agency 12% State Agency 6% Testing Laboratory 6% Geotechnical Engineering Firm 6% Federal Agency 4% Owner/Developer 4% Other 3% Percent of Respondents Type of Contact Respondents were surveyed based on their relationship with PCA in The largest percentage of respondents (69%) indicated they had used the PCA website, while 54% of all respondents have received some sort of literature or publication from PCA. Approximately two in five survey respondents had closer interaction with PCA by attending a PCA seminar or conference or direct contact with PCA staff, at 41% and 38%, respectively. Only 13% of those taking the survey had no exposure to PCA. Types of Contact with PCA PCA Website 69% Received PCA literature/publications 54% Attended PCA seminar or conference 41% Direct contact with PCA staff 38% No exposure to PCA 13% Percent of Respondents February 2018 Page 3

10 Types of Pavements Respondents were asked which types of pavements they work with. The highest number of projects represented were city (80%), state (72%), county (66%), and residential pavements (56%). Types of Pavements Used City 80% State 72% County 66% Residential 56% Parking Lots 54% Industrial Pavements 44% Federal 41% Airports 33% Tollways 21% Other 3% Percent of Respondents Number of Paving Projects When respondents were asked how many projects they have worked on over the course of the past year, the vast majority (70%) worked on 1-20 projects, with five projects being the most answered value. A response of zero paving projects was reported by 7% of respondent. The average survey participant worked on approximately 22 projects last year. Number of Pavement Projects 0 7% 1 to 20 70% 21 to to or more 7% 3% 13% 0% 10% 20% 30% 40% 50% 60% 70% 80% Percent of Respondents February 2018 Page 4

11 Level of Influence in Pavement Decisions In a new question added to the study in 2018, respondents were asked, given their position, to indicate their influence in pavement type selections, with 1 being no influence and 10 being high influence. Thirtynine percent of survey participants responded with either a 9 or 10, reflecting a high level of influence over pavement decisions. Approximately 15% reported a 1 or 2, or low influence. Level of Influence in Pavement Type Selection 1 to 2 15% 3 to 4 5% 5 to 6 22% 7 to 8 19% 9 to 10 39% 0% 5% 10% 15% 20% 25% 30% 35% 40% Percent of Respondents Average Life of Pavement Types Those surveyed were asked, on average, how many years each type of pavement lasts before needing to be replaced or requiring major rehabilitation. Concrete lasts the longest before needing to be replaced, an average of just over 29 years, according to respondents. Concrete was followed by Roller Compacted Concrete at 25 years and Thick Asphalt (>7 ) at 17.6 years. Pavement Type: Average Life (Years) Portland Cement Concrete 29.1 Thin Asphalt (<3") 10.1 Medium Asphalt (4-7") 12.5 Thick Asphalt (>7") 17.6 Roller Compacted Concrete Number of Years February 2018 Page 5

12 Subgrade Modification Awareness of Subgrade Modification Subgrade modification was defined as the stabilization and improvement of the in-situ soils below the base course. In 2018 most respondents (38%) were familiar with subgrade modification. Only 7% of respondents indicated no familiarity, which is in significant contrast to the 32% of respondents who were not familiar with subgrade modification in the 2005 study. Conversely, only 15% of participants in the 2005 survey used subgrade modification in the past year, while the 2018 survey revealed 31% of respondents as being very familiar with or using subgrade modification regularly. Awareness of Use of Subgrade Modification Not familiar 7% Somewhat familiar 25% Familiar 38% Very familiar and/or use regularly 31% 0% 5% 10% 15% 20% 25% 30% 35% 40% Percent of Respondents Projects Requiring Subgrade Modification Respondents were asked what percentage of their pavement projects within the last year required subgrade modification. Approximately one third (34%) reported less than 11% of their projects within the past year required subgrade modification. This is represents an increase in the number of projects requiring subgrade modification from the 2005, where over half (51%) of respondents states that 10% or less of their projects required subgrade modification. Around a quarter (24%) of respondents reported that subgrade modification was needed in more than 50% of their projects. Forty-three percent of survey participants required subgrade modification in 11%-50% of projects worked on within the past year. February 2018 Page 6

13 % of Projects Requiring Subgrade Modification % of Respondents 0% 20% 1%-10% 14% 11%-20% 7% 21%-30% 15% 31%-40% 2% 41%-50% 19% 51%-60% 7% 61%-70% 2% 71%-80% 2% 81%-90% 3% 91%-100% 10% Subgrade Modification Materials Used The largest percentage of subgrade modification projects worked on this past year were modified with portland cement (32%), followed by corrective aggregates (24%), geotextiles (21%), and lime (19%). Fly ash and kiln dust were used in 13% and 10% of projects, respectively, while 10% of projected used another material Subgrade Modification Materials Used Portland Cement 32% Corrective Aggregates 24% Geotextiles 21% Lime 19% Fly Ash 13% Kiln Dust 10% Other 10% 0% 5% 10% 15% 20% 25% 30% 35% Percent of Projects February 2018 Page 7

14 The percentage of subgrade modification projects using portland cement rose by 12% from 1996 to 2005 but is flat in 2018 from the levels reported in the 2005 report. The amount of similar projects using lime, according to survey participants, has fallen sharply since 1996 when 52% of projects used it. It continued to fall in the 2018 survey; 19% of respondents subgrade modification projects employed lime. Percent of Projects Using Subgrade Modification Materials Portland Cement 20% 33% 32% 32% Corrective Aggregates 24% Geotextiles 21% 29% Lime 22% 19% 28% 52% Fly Ash 10% 10% 11% 13% Kiln Dust 4% 10% 18% Other 20% 29% 10% 0% 10% 20% 30% 40% 50% 60% Likelihood to Recommend Subgrade Modification Materials On a scale of 1 to 5, with 1 being very unlikely and 5 being very likely, respondents are most likely to recommend portland cement subgrade modification (3.63), a tendency that has been increasing steadily since Fly ash (2.84) has also increased in every study since 1996 and kiln dust (2.67) has grown in the likelihood to be recommended since Geotextiles (3.54) are also likely to be recommended, at a rate virtually unchanged from the 2005 survey. In 2018, respondents were asked how likely they were to recommend corrective aggregates (3.23) and it was revealed that these materials are the third most likely to be endorsed. Lime (3.07) has been relatively unchanged throughout the four studies since February 2018 Page 8

15 Likelihood to Recommend Subgrade Modification Materials Portland Cement Corrective Aggregates 3.23 Geotextiles Lime Kiln Dust Fly Ash Mean Rating (1=very unlikely, 5=very likely) More than half of respondents rated portland cement (58%) and geotextiles (56%) as being either very likely or likely to be recommended. Fewer than half (45%) of survey participants rated corrective aggregates a 4 or 5 on the likelihood to recommend scale. Kiln dust is the least likely material to be recommended in subgrade modification with 53% of respondents suggesting they would be very unlikely or unlikely to endorse its use. Likelihood to Recommend Subgrade Modification Materials Top 2 Bottom 2 Portland Cement 58% 18% Corrective Aggregates 45% 27% Geotextiles 56% 24% Lime 38% 34% Kiln Dust 35% 53% Fly Ash 38% 41% *Top 2: Percentage of respondents with the top two responses on the scale *Bottom 2: Percentage of respondents with the bottom two responses on the scale February 2018 Page 9

16 Decision Making Variables Respondents were asked to rate cement and lime subgrade modification on several decision making variables on a scale from 1 (very poor) to 5 (excellent). Cement outperformed lime on all attributes with the exception of initial cost where it fell slightly behind lime, although cement has been improving in this metric since 1996 while lime has been falling. Strength (4.27) is perceived by respondents as cement s greatest attribute in subgrade modification with availability (4.12) and permanence of treatment (4.09) not far behind. Cement far exceeded lime in all three of these variables where lime averaged 3.14, 3.36, and 3.16 on the 1 to 5 scale, respectively. Decision Making Variables Cement vs. Lime Subgrade Modification Rating Strength Permanence of Treatment Availability Initial Cost Construction Time Drying Agent Mean Rating (1=very poor, 5=excellent) Cement Lime February 2018 Page 10

17 Subgrade Modification Ratings: Cement Lime Strength Permanence of Treatment Availability Initial Cost Construction Time Mean Rating (1=very poor, 5=excellent) Analyzing the percentage of respondents who graded cement and lime in the top two ratings (good or excellent) and the bottom two ratings (very poor or below average), it was revealed that 90% of survey participants chose a 4 or 5 in regards to cement s strength while only 1% of respondents chose a 1 or 2. This is in contrast to lime where only 46% of respondents indicated a 4 or 5 in the strength category and 24% selected a 1 or 2. Similarly, 76% and 78% of respondents chose the top two ratings for cement in permanence of treatment and availability, while only 3% and 9% chose the bottom to ratings, respectively. Over half of respondents (54%) chose the top two categories for cement s construction time in subgrade modification. Decision Making Variables Cement and Lime Subgrade Modifications Cement Lime Top 2 Bottom 2 Top 2 Bottom 2 Strength 90% 1% 46% 24% Permanence of Treatment 76% 3% 41% 24% Availability 78% 9% 51% 24% Initial Cost 34% 22% 41% 22% Construction Time 54% 15% 44% 20% Drying Age 47% 16% 50% 21% *Top 2: Percentage of respondents with the top two responses on the scale *Bottom 2: Percentage of respondents with the bottom two responses on the scale February 2018 Page 11

18 Subgrade Modification Expected Outcomes Respondents were asked what they expect to achieve with subgrade modification. Survey participants were evenly split at 48% each between expecting a permanent improvement of the subgrade soil that will enhance pavement performance but will not be considered in the structural design and those who expect a permanent improvement of the subgrade soil which will be used in the design of the pavement and given a measurable value. Only 4% of respondents elect to use subgrade modification to temporarily improve the subgrade soil to construct a working platform. Subgrade Modification Expected Outcomes Temporary improvement of the subgrade soil to construct working platform 4% Permanent improvement of the subgrade soil which will enhance pavement performance but will NOT be considered in the structural design of the pavement. 48% Permanent improvement of the subgrade soil which will be used in the design of the pavement and given a measurable value. 48% Percent of Respondents February 2018 Page 12

19 Bases Awareness of Cement Stabilized Bases Respondents were asked how familiar they were with the use of cement stabilized bases. A majority of respondents (57%) are either familiar of very family with cement stabilized bases. Only 8% of survey participants are not familiar with cement stabilized bases much different than the 2005 study which revealed 33% of respondents were not familiar and only 36% of respondents were familiar or used cement stabilized bases in the last year. Awareness and Use of Cement Stabilized Bases Not familiar 8% Somewhat familiar 34% Familiar 39% Very familiar and/or use regularly 18% 0% 5% 10% 15% 20% 25% 30% 35% 40% 45% Percentage of Projects Using Base Materials Aggregates/stone/gravel are the most used base materials among survey participants at 49%, although this has fallen quite sharply since the 2005 study where 64% of respondents indicated its use. Cement stabilized bases has grown in share of projects every year since 1996 where it accounted for a mere 5% of projects. It now stands at 17% of base projects. Base Materials Aggregate/Stone/Gravel 49% 63% 68% 64% Bituminous Mixtures 11% 18% 20% 26% Cement Stabilized 5% 9% 15% 17% Geotextiles 7% 11% Other 6% 5% 3% 4% 0% 10% 20% 30% 40% 50% 60% 70% 80% February 2018 Page 13

20 Base Material Rating Respondents were asked to rate base materials on several variables on a scale of 1 (very poor) to 5 (excellent). Comparing each examined base material on the mean rating of all responses, it was revealed that in each variable except two durability and product consistency in which cement stabilized had the highest mean scores aggregates were rated more highly among respondents than bituminous mixtures and cement stabilized as a base material. Assessing each material s perceived strengths in rank order, aggregates were rated most highly on contractor availability (4.33), designer experience (4.11), initial cost (4.04), and construction time (4.04), while bituminous mixtures were most highly rated as a base material for construction time (3.94), contractor availability (3.93), and product consistency (3.82). Cement stabilized bases were most valued as a base material for durability (4.04), product consistency (3.85), and maintenance cost (3.69). Base Materials Ratings Aggregate Bituminous Mixtures Cement Stabilized Initial Cost Maintenance Cost Durability Product Consistency Contractor Availability Construction Time Designer Experience Mean Rating (1=very poor, 5=excellent) Eighty-one percent of respondents chose a 4 or 5 when rating aggregate s contractor availability compared to 56% who selected the same ratings for cement stabilized as a material for bases. Cement stabilized as a base material rated higher than bituminous mixtures in each category except contractor availability, construction time, and designer experience so it s not surprising that respondents chose the top two ratings for cement stabilized base to a great degree than bituminous mixtures. Since the 2005 study, aggregate s rating in initial cost remained largely unchanged while cement stabilized s position improved while bituminous mixtures slipped. Aggregate Bituminous Mixtures Cement Stabilized Top 2 Bottom 2 Top 2 Bottom 2 Top 2 Bottom 2 Initial Cost 78% 7% 40% 25% 42% 18% Maintenance Cost 64% 7% 47% 20% 58% 15% Durability 60% 13% 47% 15% 78% 9% Product Consistency 67% 7% 71% 9% 71% 7% Contractor Availability 81% 4% 73% 11% 56% 16% Construction Time 73% 7% 76% 7% 52% 13% Designer Experience 76% 4% 56% 18% 37% 19% *Top 2: Percentage of respondents with the top two responses on the scale *Bottom 2: Percentage of respondents with the bottom two responses on the scale February 2018 Page 14

21 Likelihood to Recommend Base Materials On a scale of 1 to 5, with 1 being very unlikely and 5 being very likely, respondents are most likely to recommend an aggregate as a base material (4.27), a level that has been relatively flat throughout the attitudes and perceptions studies executed since Cement stabilized is now the second most likely material to be recommended by survey participants at Growth in likelihood to recommend metric improved in tandem with the percent of projects using cement stabilized base. Bituminous mixtures is now the last ranked of the base materials examined to be recommended, coming slightly behind geotextiles, which improved from the 2005 survey. Likelihood to Recommend Base Materials Aggregate/Stone/Gravel Cement Stabilized Bituminous Mixtures Geotextiles Mean Rating (1=very unlikely, 5=very likely) February 2018 Page 15

22 Sources of Information on Cement Stabilized Bases Respondents were asked which sources they use to obtain cement stabilized base information. PCA (70%) is the most common source of information followed by state DOT standards (62%) and AASHTO (40%). In a historical context, a lower percentage of respondents received their information on cement stabilized base from PCA than in the 2005 study when 85% of survey participants indicated getting information from PCA, although this still represents a quite drastic increase from levels in 1996 and Respondents have been also increasingly getting information on this subject from AASHTO and city/county agency standards in the surveys collected since Sources of Cement Stabilized Base Information Portland Cement Association 70% State DOT Standards 62% AASHTO 46% City/County Agency Standards 34% FHWA ASTM Transportation Research Board 18% 21% 25% U.S. Corps of Engineers Other 7% 11% 0% 10% 20% 30% 40% 50% 60% 70% 80% Percent of Respondents Sources of Cement Stabilized Base Information: Portland Cement Assciation 37% 45% 70% 85% State DOT Standards 57% 63% 55% 62% AASHTO 22% 33% 40% 46% City/County Agency Standards 10% 19% 22% 34% 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% Percent of Respondents February 2018 Page 16

23 Flexible Pavement Reconstruction Recycling Methods when an Asphalt Pavement Has Failed Respondents were asked when an asphalt pavement fails (can no longer be resurfaced due to inadequate base support among other reasons), what percent of the time each of the following options are used. The most commonly used method is to tear up road and rebuild with a new material (34%) which represents a decrease in percentage from the 2005 survey (39%), followed by full-depth reclamation (30%) which increased slightly from the 2005 report s 29% of responses. The percent of respondents who answered that they would delay the project (5%) increased slightly from that of the 2005 study (4%). Recylcing Methods - When an Asphalt Pavement Has Failed Tear up road and rebuild with new material 34% Full-Depth Reclamation 30% Resurface with thick structural overlay 14% Thin overlay with minor base repair 13% Delay project 5% Other 3% Percent of Respondents Likelihood to Recommend Using Each Stabilizer for Recycling Projects Survey participants were asked how likely they are to recommend full-depth reclamation of failed pavement with each of the following stabilizers on a scale of 1 (very unlikely) to 5 (very likely). Those surveyed are most likely to recommend using FDR with corrective aggregates with a mean score of 3.90, followed by cement (3.58) and asphalt emulsion (2.64). Not using a stabilizer is the least likely to be recommended for a recycling project. Likelihood to Recomment Using Each Stabilizer for Recycling Projects Corrective Aggregates 3.90 Cement 3.58 Cement Kiln Dust/Lime Kiln Dust 2.48 Lime 2.51 Fly Ash 2.31 Asphalt Emulsion 2.64 Foamed Asphalt 2.40 Not use a stabilizer 2.11 Mean Rating (1=very unlikely, 5 = very likely) February 2018 Page 17

24 The likelihood among the paving professionals surveyed to choose cement for full-depth reclamation projects increased from the 2005 and has expanded significantly since Over the same period, respondents were less inclined to recommend lime, although it rebounded slightly since the 2005 study. Likelihood to Recommend Using Each Stabilizer for Recycling Pavements: Cement Lime Fly Ash Foamed Asphalt Asphalt Emulsion Not Use a Stabilizer Mean Rating (1=very unlikely, 5=very likely) Types of Stabilizers in FDR Projects The highest percent of FDR projects worked on by survey participants use corrective aggregates as a stabilizer (31%) followed by cement (30%). Respondents reported that in 12% of their FDR projects, a stabilizer was not used. Types of Stabilizers in FDR Projects Corrective Aggregates 31% Cement 30% Cement Kiln Dust/Lime Kiln Dust 5% Lime 7% Fly Ash 7% Foamed Asphalt 5% Not use a stabilizer 12% Other 5% Percent of Projects February 2018 Page 18

25 The amount of projects in which some sort of stabilizer is used is now at its highest level (88%) in stark contrast to 2002 when 40% of recycling projects did not use a stabilizer. The number of cement projects (30%) fell slightly since the 2005 survey but has seen large growth since The use of lime in FDR projects (7%) among respondents in 2018 was its lowest level recorded in this study. Types of Stabilizers in Recycling Projects: Cement 19% 20% 30% 33% Lime 7% 11% 9% 9% Foamed Asphalt 0% 2% 5% 5% Fly Ash 7% 5% 5% 7% No Stabilizer Used 12% 25% 37% 40% Other 6% 8% 9% 5% 0% 5% 10% 15% 20% 25% 30% 35% 40% 45% Percent of Projects February 2018 Page 19

26 Roller-Compacted Concrete (RCC) Pavements Types of Pavements Used for Projects The paving professionals surveyed were asked what percentage of projects within the past five years used of each of the following materials. The highest percentage of projects used asphalt (62%) followed by conventional concrete (24%). Compared to the 2005 survey, asphalt s use increased from 55% and conventional concrete s diminished from 30%. The percentage of projects employing RCC with a conventional concrete surface, however, increased since Types of Pavements Used for Projects Asphalt 62% Conventional Concrete 24% RCC (Unsurfaced) 5% RCC (With Asphalt Surface) 3% RCC (With Conventional Concrete Surface) 5% Other 1% Percent of Projects Awareness of RCC Pavements Familiarity with RCC pavement systems increased dramatically in the 2018 survey with 92% of all respondents now familiar with RCC. In 2005, 45% of those surveyed were not familiar with RCC. Over half (52%) of respondents reported being somewhat familiar with RCC, followed by 33% who indicated they were familiar with RCC pavements. In 2005, 32% of respondents were somewhat familiar with and 18% were familiar with RCC pavements. Awareness and Use of RCC Not familiar 8% Somewhat familiar 52% Familiar 33% Very familiar and/or use regularly 6% 0% 10% 20% 30% 40% 50% 60% Percent of Respondents February 2018 Page 20

27 Likelihood to Recommend RCC On a scale of 1 (very unlikely) to 5 (very likely), respondents were asked to rate the likelihood they would recommend RCC for several specific applications. Heavy industrial/intermodal projects (3.33) are the most likely candidates for RCC applications, followed by commercial parking/storage (3.21). Both commercial parking/storage and public roadways (<35 mph) have increased in their likelihood to be recommended for RCC in every survey since 2002, while heavy industrial/intermodal and public roadways (>35 mph) decreased in their propensity to be recommended for RCC since Likelihood to Recommend RCC for Specific Applications Heavy Industrial/Intermodal Commercial Parking/Storage Public Roadways (<35 mph) Public Roadways (>35 mph) Mean Rating (1=very unlikely, 5=very likely) Unsurfaced RCC, Conventional Concrete, & Full-Depth Asphalt Ratings Respondents were asked to rate unsurfaced RCC, conventional concrete, and full-depth asphalt pavements on several variables a scale of 1 (very poor) to 5 (excellent). Full-Depth Asphalt was the highest rated of the three options in every variable except three maintenance cost, durability, and roughness. In each of these cases, conventional concrete was the highest rated except on maintenance cost where it tied with unsurfaced RCC. Unsurfaced RCC was ranked third - or the least rated material - in most attributes, with the exception of being tied for first in maintenance cost (3.38), and second in durability (3.70), construction time (3.35), and initial cost (3.13). Conventional concrete was rated highest for its durability (4.16) followed by appearance (4.11), surface texture (4.02), and contractor availability (3.93). Initial cost (2.96) and construction time (3.04) were perceived weaknesses for conventional concrete by respondents. Full-depth asphalt was rated highest for its contractor availability (4.25) and surface texture (4.25), followed by appearance (4.24) and designer experience (3.95). It rated lowest on maintenance cost (3.33) and durability (3.60). February 2018 Page 21

28 Unsurfaced Conventional RCC Concrete Full-Depth Asphalt Appearance Surface Texture Cracking Initial Cost Maintenance Cost Durability Roughness Contractor Availability Ease of Maintenance Construction Time Designer Experience Homeowner/Business Inconvenience Mean Rating (1=very poor, 5=excellent) The table below demonstrates the material ratings by the percentage of top two and bottom two selections. Unsurfaced RCC only broke 50% of respondents choosing a 4 or 5 rating in two variables durability (58%) and construction time (52%). Conventional concrete and full-depth asphalt were both highly rated on appearance and surface texture with 77% and 82% of respondents choosing the top two ratings for conventional concrete and 82% and 84% of survey participants choosing the same for fulldepth asphalt, respectively. Eighty-four percent of respondents indicated a good or excellent rating in regards to full-depth asphalt s contractor availability Performance Rating - RCC, Conventional Concrete, FDR RCC (Unsurfaced) Conventional Concrete Full-Depth Asphalt Top 2 Bottom 2 Top 2 Bottom 2 Top 2 Bottom 2 Appearance 36% 28% 77% 2% 82% 5% Surface Texture 39% 30% 82% 4% 84% 5% Cracking 28% 24% 43% 21% 48% 13% Initial Cost 38% 26% 32% 34% 54% 16% Maintenance Cost 47% 21% 50% 18% 41% 16% Durability 58% 11% 82% 2% 48% 14% Roughness 34% 23% 61% 13% 57% 13% Contractor Availability 32% 38% 73% 9% 84% 7% Ease of Maintenance 38% 19% 54% 20% 66% 9% Construction Time 52% 27% 39% 34% 68% 13% Designer Experience 31% 38% 64% 14% 71% 9% Homeowner/Business Inconvenience 40% 29% 38% 24% 67% 9% *Top 2: Percentage of respondents with the top two responses on the scale *Bottom 2: Percentage of respondents with the bottom two responses on the scale February 2018 Page 22

29 Public vs. Private Projects Respondents were asked what percent of projects were either public or private/commercial when the following materials were used. In each instance, there were more public projects undertaken, in some instances by quite a significant margin. Cement stabilized base and full-depth reclamation with cement have the highest concentration in public construction at 73% each. The percentage of cement subgrade modification among respondent s projects was 64% with the remaining 36% private/commercial. RCC pavements had the highest proportion in private projects at 43%. Percent of Projects: Public vs. Private Cement Subgrade Modification 36% 64% Cement Stabilized Base Full-Depth Reclamation with Cement 27% 27% 73% 73% RCC Pavement 43% 57% 0% 10% 20% 30% 40% 50% 60% 70% 80% Public Private Fugitive Dust Concern Respondents were asked how much of a concern fugitive dust from the spreading of dry stabilizers (e.g. lime, cement, fly ash) is vs. slurry placement in urban and rural settings. The spreading of fugitive dust from dry stabilizers is of much greater concern in urban areas with 71% of respondents indicating concern (prefer slurry placement) or major concern (only allow slurry placement) in urban projects. In rural areas, virtually the opposite is true with 68% of survey participants expressing minor or no concern with fugitive dust in rural settings. Concern: Fugitive Dust from Spreading of Dry Stabilizers vs. Slurry Placement Rural Urban No Concern 12% 7% Minor Concern 56% 22% Concerned (prefer Slurry Placement) 20% 49% Major Concern (only allow Slurry Placement) 12% 22% Percent of Respondents February 2018 Page 23

30 Future Trends Overall, the outlook among the surveyed paving professionals is very positive for cement-based pavements. The optimistic outlook is pervasive throughout all the cement-based pavement materials examined and with the exception of RCC pavement, the percentage of respondents who expect these cement paving systems to increase is substantially larger than suggested in the 2005 study. Respondents were asked how they thought the use of each material would perform over the next five years. Approximately 70% of respondents believe FDR with cement will increase over the next five years with a full 24% believing it will increase substantially. Similarly, 67% of survey participants believe cement stabilized base will increase, with only 2% expecting a slight decline. Roughly 65% of respondents foresee an increase in cement stabilized subgrade. Just under half (49%) of respondents believe RCC pavement will increase, with 40% believing its use over the next five years will stay the same. No respondent in any category believes the use of the examined cement-based pavement systems will decrease significantly. Trends 2018 Cement Stabilized Subgrade 3% 32% 44% 20% Cement Stabilized Base 2% 32% 53% 14% Full-Depth Reclamation with Cement 12% 19% 46% 24% RCC Pavement 11% 40% 33% 16% 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Percent of Respondents Decrease Slightly Stay the Same Increase Slightly Increase Substantially Trends 2005 Cement Stabilized Subgrade 8% 45% 47% Cement Stabilized Base 4% 47% 49% Full-Depth Reclamation with Cement 11% 51% 38% RCC Pavement 5% 44% 50% 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Decrease Percent of Respondents Stay the Same Increase February 2018 Page 24

31 5420 Old Orchard Road Skokie, Illinois Fax Contacts: Edward J. Sullivan, Sr. Vice President and Chief Economist Wayne Adaska, Director, Pavements Brian Schmidt, Economist II Connecticut Ave., NW, Suite 500 Washington, DC Fax Portland Cement Association