Astm stp 1222 1994

STP 1222 Buried Plastic Pipe Technology: 2nd Volume Dave Eckstein, Editor ASTM Publications Code Number (PCN): 04-012220-58 ASTM 1916 Race Street Philadelphia, PA 19103 Printed in the U.S.A Library of Congress Cataloging-in-Publication Data Buried plastic pipe technology: 2nd volume / Dave Eckstein, editor (Special technical publication ; 1222) "Papers presented at the symposium held in New Orleans, LA from 28 Feb to March 1994" CIP foreword Includes bibliographical references and index ISBN 0-8031-1992-5 Underground plastic pipe Congresses II Eckstein, Dave 1954II American Society for Testing and Materials III Series: ASTM special technical publication ; 1222 TJ930-B873 1994 94-10977 CIP Copyright 1994 AMERICAN SOCIETY FOR TESTING AND MATERIALS, Philadelphia, PA All rights reserved This material may not be reproduced or copied, in whole or in part, in any printed, mechanical, electronic, film, or other distribution and storage media, without the written consent of the publisher Photocopy Rights Authorization to photocopy items for internal or personal use, or the internal or personal use of specific clients, is granted by the AMERICAN SOCIETY FOR TESTING AND MATERIALS for users registered with the Copyright Clearance Center (CCC) Transactional Reporting Service, provided that the base fee of $2.50 per copy, plus $0.50 per page is paid directly to CCC, 222 Rosewood Dr., Danvers, MA 01923; Phone: (508) 750-8400; Fax: (508) 750-4744 For those organizations that have been granted a photocopy license by CCC, a separate system of payment has been arranged The fee code for users of the Transactional Reporting Service is 0-8031-1992-5/94 $2.50 -t- 50 Peer Review Policy Each paper published in this volume was evaluated by three peer reviewers The authors addressed all of the reviewers' comments to the satisfaction of both the technical editor(s) and the ASTM Committee on Publications To make technical information available as quickly as possible, the peer-reviewed papers in this publication were printed "camera-ready" as submitted by the authors The quality of the papers in this publication reflects not only the obvious efforts of the authors and the technical editor(s), but also the work of these peer reviewers The ASTM Committee on Publications acknowledges with appreciation their dedication and contribution to time and effort on behalf of ASTM Printed in Baltimore,MD May 1994 Overview The second symposium on Buried Plastic Pipe Technology is just what the title implies, a sequel to the first Given the success of the first symposium, the instruction from the steering committee was brief and succinct, "Follow exactly the format from the first symposium, but ensure that the content represents state-of-the-art technical input for today." Four years having elapsed, coupled with the ever-expanding topic of buried plastic pipes facilitated accomplishing this goal The papers are categorized into five sections of: Field Testing, Design and Installation, Rehabilitation, Laboratory Testing, and Trenchless Construction Howard et al report detailed field measurements ofa 915-mm fiberglass pipe installation in the former USSR, now Latvia I D Moore introduces a three-dimensional viscoelastic finite-element model to predict circumferential stress and strain in HDPE pipes The paper compares results with that of conventional parallel plate stiffness evaluation in predicting actual behavior Next, A Howard reports on the Bureau of Reclamation's 25 years of experience with soil-cement slurry pipe bedding Critical parameters are defined and discussed L J Petroff offers a design methodology for buried HDPE manholes that accounts for both the ring-directed and axially-directed effects of applied earth pressure Groundwater loadings and "downdrag" of surrounding soil are also investigated The controlled expansion of conventionally extruded PVC pressure pipe produces a preferred molecular orientation that results in increased tensile strength and other performance enhancements D E Bauer reports on over a decade of field experience and research and testing with oriented PVC pipe Two papers provide analysis of rehabilitation techniques on two completely different aspects of their application D G Kleweno reports on chemical exposures to six commercially available resins for cured-in-place pipe rehabilitation Lo and Zhang propose two separate collapse models for encased pipes Special attention is given to the analysis of the annular gap between the two pipes and the effects of hydrostatic loading and temperature variations The next section, Laboratory Testing, provides four papers on a wide range of investigated parameters Woods and Ferry report on the phenomenon of compressive buckling of hollow cylinders during pressure testing When the phenomenon may exhibit itself and specific recommendations for test apparatus are included A new test for studying behavior of buried plastic pipes in hoop compression is presented by Selig et al A cylindrical steel vessel with an inflatable bladder serves as the core apparatus for this new test procedure Leevers et al provide an extensive investigation of rapid crack propagation in polyethylene pipe materials Several test methods and their relative ability to predict RCP in polyethylene are presented The effects of acid environment on PVC pipes is presented in two papers back-to-back Sharffand DelloRusso report on a two-year study exposing PVC pipes held at a constant 5% deflection to 1.ON solution of sulfuric acid with minimal effect Hawkins and Mass, who begin the section on Trenchless Construction, report on results of 14-day to 6-month exposures of calcium-carbonate filled PVC pipes to 20% sulfuric acid environments Scanning electron microscopy and wavelength dispersive x-ray microanalysis are vii viii OVERVIEW used to provide qualitative and quantitative effects to the calcium carbonate and PVC combination Tohda et al conclude a non-conservative possibility with current Japanese design standards for predicting bending moment and pipe deflection when pipes are installed open excavation using sheet piling Centrifuge model tests used to reach this conclusion are described in detail McGrath et al investigate the effect of short-term loading to a polyethylene pipe already subjected to long-term load An example would be traffic loading on a buried pipe The simulating test protocol is described and results reported The final three papers by Iseley et al., Najafi and Iseley, and Brown and Lu complete this publication The first (perhaps more appropriately rehabilitation) categorizes and summarizes six trenchless methods as cured-in-place pipes, sliplining, in-line replacement, deformed and reshaped, point source repair, and sewer manhole rehabilitation The second paper chronicles a full-scale test of PVC profile wall sewer pipe for microtunneling using a new microtunneling propulsion system The final paper by Brown and Lu investigates RCP in polyethylene gas pipes specific to the effects of loading rates The goal of the symposium and this STP was to provide an update in the technology of buried plastic pipe We hope you agree that we have succeeded I would like to extend my personal gratitude to all of those who contributed to the success of this effort but who might otherwise go unrecognized Special thanks to the ASTM staff, the steering committee, and the many reviewers of these papers Dave Eckstein Uni-Bell PVC Pipe Association 2655 Villa Creek Dr., Suite 155, Dallas, TX 75234; symposium chairman and editor Contents Overview vii FIELD TESTING Latvia Field Test of 915-mm Fiberglass Pipe A HOWARD, J B SPRIDZANS, AND B J S C H R O C K DESIGN AND INSTALLATION Profiled H D P E Pipe Response to Parallel Plate Loading i D MOORE 25 Installation of Plastic Pipe Using Soil-Cement Slurry A K HOWARD 41 Design Methodology for High Density Polyethylene Manholes L J PETROFF 52 Oriented PVC Pipe (PVCO): Experience and R e s e a r e h - - o E BAUER 66 REHABILITATION Physical Properties and Chemical Resistance of Selected Resins for Cured-in-Place Pipe Rehabilitation D G KLEWENO 79 Collapse Resistance Modeling of Encased Pipes K n LO AND J Q ZHANG 97 LABORATORY TESTING Compressive Buckling of Hollow Cylinders: Implications for Pressure Testing of Plastic P i p e - - D W WOODS AND S R FERRY 113 Laboratory Test of Buried Pipe in Hoop Compression E X SELIG, L C D I F R A N C E S C O , A N D T J M C G R A T H 119 Rapid Crack Propagation Along Pressurized Plastic P i p e - - P s LEEVERS, G P V E N I Z E L O S , A N D R E M O R G A N 133 Effects of Acid Environment and Constant Deflection on PVC Sewer P i p e - P A S H A R F F A N D S J D E L L O R U S S O 149 TRENCHLESS CONSTRUCTION The Effects of Sulfuric Acid on Calcium Carbonate Filled PVC Sewer Pipe Compounds T w HAWKINS AND T R MASS 167 Analysis of the Factors in Earth Pressure and Deformation of Buried Flexible Pipes Through Centrifuge Model T e s t s - - J TOHDA, L LI, AND H YOSHIMURA 180 Stiffness of H D P E Pipe in Ring Bending T J MCGRATH, E T SELIG, AND L C D I F R A N C E S C O 195 Trenchless Pipeline Rehabilitation with Plastic Materials D T ISELEY, M N A J A F I , A N D R D B E N N E T T Evaluation of PVC Pipe for Microtunneling M NAJAFI AND D T ISELEY 206 220 The Effect of Loading Rate on Rapid Crack Propagation in Polyethylene P i p e s - N B R O W N A N D X L U 234 Author Index 245 Subject Index 247 Field Testing Amster Howard,' Juris B Spridzans,' and B J Schrock3 LATVIA FIELD TEST OF 915-mm FIBERGLASS PIPE REFERENCE: Howard, Amster, Spridzans, J B., and Schrock, B J., Latvia Field Test of 915-mm Fiberglass Pipe," Buried Plastic PiDe Technoloqv: 2nd Volume, ASTM STP 1222, Dave Eckstein, Ed., American Society for Testing and Materials, Philadelphia, 1994 ABSTRACT: The USA and USSR jointly constructed a special test section of - m diameter Reinforced Plastic Mortar (RPM) fiberglass pipe in June 1979 near Riga, Latvia This experiment was part of the working agreement of the US-USSR team "Investigations of Effectiveness of Plastic Pipe in Drainage and Irrigation." Measurements were made of pipe deflections, soil properties, and in-place densities Six different embedment conditions were used The pipe deflections were measured during each state of construction and over a 4-year period Data of particular interest is the increase in the vertical diameters caused during soil compaction at the sides of the pipe and the frequent deflection measurements in the few weeks following the final placement of the m of backfill over the pipe The ratio of the vertical deflection after years to the vertical deflection on the day the backfilling was completed ranges from 1.6 to 1.7 for the dumped side support, 4.5 for a side support with a moderate degree of compaction, and 2.2 to 2.9 for the side support placed to a high degree of compaction KEY WORDS: pipe, fiberglass pipe, flexible pipe, deflection, test section, soil mechanics, soil tests, time factors, casper, soilstructure interaction This paper reports the results of deflections measured over years for - m RPM (reinforced plastic mortar) pipe buried as part of a twocountry joint experiment Research Civil Engineer, U.S Bureau of Reclamation, PO Box 25007, Denver CO 80225 Chief, Polymer Conduits Branch, VNII Vodpolimer, 229601 Jelgava, Latvia President, B.J.S Engineering Co , Sacramento, California BURIEDPLASTIC PIPE TECHNOLOGY The e x p e r i m e n t was c o n d u c t e d to e v a l u a t e the l o a d d e f l e c t i o n b e h a v i o r of b u r i e d R P M pipe The pipe was i n s t a l l e d in 1979 w i t h six d i f f e r e n t e m b e d m e n t c o n d i t i o n s at a site n e a r Riga, Latvia This i n s t a l l a t i o n was u n i q u e in that m e a s u r e m e n t s made at each i n c r e m e n t of c o n s t r u c t i o n r e s u l t e d in d a t a v e r y s e l d o m collected The r e s u l t was i n c r e a s e d k n o w l e d g e about the change in the v e r t i c a l d i a m e t e r s d u r i n g c o m p a c t i o n a l o n g s i d e the pipe, d e f l e c t i o n s r e l a t e d to level of b a c k f i l l over the pipe, a n d the i n c r e a s e in d e f l e c t i o n d u r i n g the first few days and weeks following installation T h i s e x p e r i m e n t was p a r t of the w o r k i n g a g r e e m e n t of the U S - U S S R team, " I n v e s t i g a t i o n of E f f e c t i v e n e s s of P l a s t i c Pipe in D r a i n a g e and Irrigation." The t e a m was part of the S o v i e t - A m e r i c a n Joint C o m m i s s i o n on S c i e n t i f i c a n d T e c h n i c a l C o o p e r a t i o n P r o g r a m that was active from 1972 to 1982 T h i s p a p e r is a stur~ary of a series of B u r e a u of R e c l a m a t i o n internal m e m o r a n d u m s i s s u e d f r o m 1979 to 1989 [i] PIPE The R P M p i p e is 915 m m inside d i a m e t e r w i t h a p p r o x i m a t e l y 10-mm wall t h i c k n e s s and was r a t e d at 450 feet of head The p i p e was m a n u f a c t u r e d in Riverside, California, and s h i p p e d to Latvia Parallel plate tests on sections of the p i p e s h o w e d the E I / r of the p i p e to be about 18 k N / m (2.6 ib/in2) The pipe to be m o n i t o r e d in the test reach are 5.5 m long, and the t r a n s i t i o n a l p i e c e s b e t w e e n the m o n i t o r e d sections are 2.7 m long The pipe has bell- and s p i g o t - t y p e joints CONSTRUCTION A typical cross s e c t i o n for the six b e d d i n g p i p e is shown on f i g u r e I conditions for the R P M The n a t u r a l m o i s t u r e and d e n s i t y of the t r e n c h wall material, a sandy clay, was d e t e r m i n e d b y b o t h a sand cone device a n d a d e n s i t o m e t e r m o i s t u r e gauge The t r e n c h w a l l s w e r e firm, h a v i n g a d e n s i t y of about 2.0 M g / m 3, a n d h a d a m o i s t u r e c o n t e n t of about 13 percent A b o u t a - m m l a y e r of sand (same source as the sand u s e d beside the pipe) was s p r e a d in the b o t t o m of the t r e n c h a n d the b o t t o m fine graded T w o - m sections of - m m - i n s i d e - d i a m e t e r r e i n f o r c e d concrete pipe were p l a c e d at the d o w n s t r e a m end of the test s e c t i o n w h i c h d a y l i g h t e d on the b a n k of a lake The R P M pipe was t h e n laid and joined At the end of the R P M p i p e section, a m a n h o l e was c o n s t r u c t e d u s i n g p r e c a s t r e i n f o r c e d c o n c r e t e rings to p r o v i d e access into the pipe A f t e r laying the pipe, a small w e d g e of soil was p u s h e d into the pipe h a u n c h a r e a a n d h a n d c o m p a c t e d to p r e v e n t s i d e w a y s d i s p l a c e m e n t of the pipe At this point, the first d i a m e t e r m e a s u r e m e n t s p i p e w i t h an inside m i c r o m e t e r and d e f l e c t o m e t e r were made in the RPM The d e f l e c t o m e t e r c o n t i n u o u s l y r e c o r d e d on a strip chart the vertical and h o r i z o n t a l d i a m e t e r of the pipe as it was p u l l e d t h r o u g h the pipe E oo E E po Z'0 " E HOWARD ET AL ON 915-MM FIBERGLASS PIPE E o o I.o I= FIG - - T y p i c a l T r e n c h D i m e n s i o n s a n d C r o s s - S e c t i o n 238 BURIED PLASTIC PIPE TECHNOLOGY longer and if the loading rate was greater than about 40x104 N/s The change in slope beyond 50 mm is associated with end effects as the specimen bends When the length of rapid fracture is more than 50 mm which is times the thickness, then it is expected RCP would proceed indefinitely as determined by the length of the specimen Fig Load-time curves and Displacement-time curves (a) 84x104 N/s; (b) 42x104 N/s; (c) 35x104 N/s; (d) 24x104 N/s BROWN AND LU ON RAPID CRACK PROPAGATION 239 Fig Specimens fractured at 10~ at various loading rates (a) 93 x 10 N/s, long range rapid fracture (b) 35 • 10 N/s, short range rapid fracture (c) 23 • 104 N/s, no rapid fracture ,oo = ~u I 80 I 60 40 2o e/ 28~ A / Loading Rate(I05N/Sec) Fig Length of rapid fracture versus loading rate Dotted line would correspond to an extremely long specimen 10 BURIED PLASTICPIPETECHNOLOGY 240 Table I - Effect of Loading Rate on RCP and Specimen 21 24 26 25 22 23 18 20 19 17 Specimen 11 10 12 27 Loading Rate (10n N/s) 24 24 31 35 41 42 71 84 93 93 Loading Rate (10n N/s) 22 29 29 58 60 88 IO~ Tests Distance of Rapid Fracture (mm) Ktc at 10~ and 28~ Ktc (MPa-m ~) 35 88 86 88 84 91 95 Maximum Load (103 N) 14.1 14.1 12.8 12.4 12.4 11.8 10.2 11.8 13.2 13.1 28~ Tests Distance of Rapid Fracture (ram) 4 Maximum Load (103 N) 10.9 10.9 10.9 11.6 10.9 10.2 Ktc (MPa m ~) No Fracture NoFracture 3.84 3.87 3.71 3.56 3.13 3.62 4.05 3.96 av 3.7_+0.3 No Fracture 3.29 3.29 3.63 3.29 3.08 av 3.3_+0.2 The data at 28~ show that a small length of rapid fracture can be initiated at about a loading rate greater than 29x104 N/s, but even at a loading rate of 88x104 N/s, the rapid fracture could only travel about mm which is only 1/2 times the pipe thickness This result is expected because the energy for fracture greatly increases with temperature Since 88x104 N/s was about the highest loading rate that can be achieved with our tensile machine, it is not known whether long rage brittle fracture can be produced in this specimen at 28~ Table I shows how the maximum load varies with loading rate The maximum load coincides with the initiation of rapid fracture because beyond the maximum load the load very rapidly decreases Therefore the maximum load can be converted to a Ktc which is defined as the stress intensity to initiate fracture where 241 BROWN AND LU ON RAPID CRACK PROPAGATION K1c = Ycra~ (2) cr is the stress; a is the notch depth and Y is the geometric and loading factor For our single edge notched specimen whose ratio of notch depth to specimen width is 0.2, Y = 2.43 as given by Williams [.6_] For the loading rates from 31x104 to 93x104 N/s., Ktc was practically independent of loading rate with an average value of 3.7_+0.3 MPa m ~ at 10~ and 3.3i-0.2 MPa m ~ at 28~ It is interesting to note that Barry and Delatycki [2] determined Ktc for a group of polyethylenes at 23~ under three point bending for strain rates from -2x10 -7 s-1 to 0.1 s -1 They found that over this range of strain rates Ktc increased by a factor of 3-4 In our experiments the strain rates were only varied by a factor of so that our variation in strain rates was too small to produce a significant change in Ktc The input energy up to peak load was measured from the area under the curve of load versus time and from the displacement versus time curves The input energy, when fracture was initiated, is given by E = LmaxDmax 30 (3) / k I,_ rILl 20 Q m & 10 ~ ~3 I i I I Loading Rate (10s N/see) Fig Relative input energy at peak load versus laoding rate 10 242 BURIED PLASTIC PIPE TECHNOLOGY where Lmax and Dm~x are the maximum load and the corresponding displacement Fig shows the plot of E versus loading rate at 10~ There is a rapid decrease in E when RCP occurs Lee, et al ~] measured the fracture toughness and crack instability in tough polymers under plane strain conditions They found that in general there was a decrease in the fracture energy when rapid fracture occurred This decrease in energy was caused by a transition from multiple crazing to the single craze that is associated with rapid fracture Summary The stress intensity, Klc, to initiate fracture is independent of the loading rate However the initiation of unstable rapid fracture occurs above a critical loading rate To produce RCP, long range rapid fracture, requires a further increase of loading rate by about 50% The input energy required to initiate fracture depends on loading rate where the energy to initiate r~pid fracture is about ten times the energy required to produce long range rapid fracture Thus a rapid low energy impact is more likely to produce RCP than a slow high energy impact Whereas RCP can be produced at 0~ it was not possible to produce RCP at 28~ with a high speed servo hydraulic machine for the particular gas pipe used in this investigation References [1] [2] [3_] [_4] [5_] [fi] [_7.] [8] Greig, J M., "Rapid Crack Propagation in Hydrostatically Pressurized 250 mm Polyethylene Pipe", Paper 12, 7'th International Conference Plastic Pipes, Bath, England (19-22 September 1988) Yayla, P and Lecvers, P S., "A Novel Technique for the Study of Rapid Crack Propagation In Plastic Pipes", 8'th European Conference on Fracture, Torino, Italy (1-5 October, 1990) Kanninen, M F., Leung C.-P., Grigory S C., Couque, H R and Popelar, C F "A Fracture Mechanics Methodology for Preventing Rapid Crack Propagation in PE Gas Distribution Pipes" Twelve Plastic Fuel Gas Pipe Symposium, Boston, Mass (24-26 September 1991) p 70 Leevers, P.S and Yayla, P., "Thickness Effects on Rapid Crack Propagation in Polyethylene Pipe", ibid p 58 Mandell, J F., Roberts S R., McGarry, F J., "Plane Strain Fracture Toughness of Polyethylene Pipe Materials" Polymer Engineering and Science, Vol 23, (1983) 404 Williams, J G., "Fracture Mechanics of Polymers", pub John Wiley & Sons, New York (1984) p 66 Barry, D B and Delatycki, O., "The Strain Rate Dependency of Fracture in Polyethylene: Fracture Initiation", J of App Poly Sci., vol 38, (1989) 339 Lee, L H., Mandell, J F., and McGarry, F J., "Fracture Toughness and Crack Instability in Tough Polymers Under Plane Strain Conditions", Polymer Engineering and Science, 27 (1987) 128 BROWN AND LU ON RAPID CRACK PROPAGATION 243 ACKNOWLEDGMENT The research was sponsored by the Gas Research Institute The central facilities as provided by the NSF-MRL grant DMR 91-20668 were most helpful The assistance of Dr Alex Radin was invaluable AUTHOR INDEX Index Terms Links B Bauer, D E 66 Bennett, R D 206 Brown, N 234 D Dellorusso, S J 149 DiFrancesco, L C 119 195 F Ferry, S R 113 H Hawkins, T W Howard, A K 167 41 206 220 I Iseley, D T K Kleweno, D G 79 This page has been reformatted by Knovel to provide easier navigation Index Terms Links L Leevers, P S 133 Li, L 180 Lo, K H Lu, X 97 234 M Mass, T R 167 McGrath, T J 119 Moore, I D Morgan, R E 195 25 133 N Najafi, M 206 220 P Petroff, L J 52 S Schrock, B J Selig, E T 119 Sharff, P A 149 Spridzans, J B 195 T Tohda, J 180 This page has been reformatted by Knovel to provide easier navigation Index Terms Links V Venizelos, G P 133 W Woods, D W 113 Y Yoshimura, H 180 Z Zhang, J Q 97 This page has been reformatted by Knovel to provide easier navigation SUBJECT INDEX Index Terms Links A Acid effects 149 167 ASTM standards D 2412 149 D 3034 149 Bending strain 180 Bladder, inflatable 119 B Buckling compressive 52 progressive 97 Calcium carbonate 167 113 C Casper Cement, soil, slurry 41 Centrifuge test 180 Charpy 133 Chemical resistance 79 Collapse resistance 97 Compaction Compression, hoop 41 119 This page has been reformatted by Knovel to provide easier navigation Index Terms Links Compressive strain 52 Compressive strength 41 Construction Productivity Advancement Research 206 Crack growth propagation, rapid resistance Cured-in-place pipe 133 234 66 79 97 206 149 180 D Deflection 195 Deformation 180 195 Design 206 220 limits 119 standards 180 E Encased pipes 97 Epoxy 79 Excavation method 180 F Fatigue resistance Fiberglass pipe Finite element analysis Flexibility Flexible pipe Fly ash 66 25 180 52 41 This page has been reformatted by Knovel to provide easier navigation 180 Index Terms Links G Gap effect, radial Gas pipes 97 133 234 H Hoop compression 119 Hydrostatic Design Basis 66 Hydrostatic pressure 97 I Impact resistance 66 Installation 41 sewer pipe Irwin Corten expression 180 220 133 L Laboratory tests Loading hoop compression 119 52 119 parallel plate 25 rate 25 Local strain 25 234 M Manholes 52 Marston-Spangler theory 180 Microscopy 167 This page has been reformatted by Knovel to provide easier navigation 206 Index Terms Links O Oriented pipe 66 P Plastic pipe (See also specific types) buckling cured-in-place hoop compression installation 113 79 97 206 52 133 66 149 119 41 rapid crack propagation 133 ring bending 195 Plate loading 25 Polyester 79 Polyethylene 25 234 Poly vinyl chloride 41 220 pipe compound Pressure pipe Pressure testing 167 66 133 113 R Radial gap effect 97 Rapid crack propagation 133 Rapid long range fracture 234 234 Rehabilitation cured-in-place pipe techniques 79 206 This page has been reformatted by Knovel to provide easier navigation Index Terms Reinforced plastic mortar Links Relaxation modulus 195 Ring bending 195 41 S Scanning electron microscopy 167 Sewer acid 149 167 Sewer pipe 149 167 220 Short-term modulus 195 Sliplining 206 25 52 79 149 195 Slurry 41 Soil cement soil 41 Soil loads 220 Soil mechanics Soil-structure interaction Soil tests Standards ASTM D 2412 149 D 3034 149 international pipe test 133 Japanese design 180 Stiffness Strain 52 Stress relaxation 149 Sulphuric acid 149 aging 195 167 This page has been reformatted by Knovel to provide easier navigation Index Terms Links T Thermoplastic 52 Thermoset resins 79 Thickness Thin ring theory 133 25 Trenchless technology 206 Tunneling 220 220 V Vinyl ester 79 Viscoelasticity 25 149 W Water pipes 133 X X-ray microanalysis 167 Y Young’s modulus 195 This page has been reformatted by Knovel to provide easier navigation 195