CIGMAT Report: Update From This Unique, Industry-Specific Ongoing Research Program

By C. Vipulanadan, PhD, P.E., professor of Civil Engineering, director of CIGMAT and the Texas Hurricane Center for THC-IT | September 2010 Vol. 65 No. 9
1) Macro-cells 2) Macro-holes in the Macro-cell walls 3) Macro-cell walls. Fig. 1: Microstructure of a polyurethane grout.

The overall objective of the test protocol was to systematically evaluate grouts for infiltration control in wastewater systems and to control leaks in concrete structures. The specific objectives are: (1) to evaluate the working, mechanical and durability of grouts and grouted soils; (2) to characterize the grout-substrate interaction and durability; and (3) to verify the performance of grouted joints and repaired concrete cracks under dry and hydrostatic pressure (241 kPa (35 psi) up to 5 psi in 10 feet of water) using model tests over a period of one month.

Tests were performed using relevant ASTM and CIGMAT standards. Over 10 different grout tests were used to characterize the grouts. Several additional tests were performed with grouted soil and grout-substrate interaction. Four model tests representing various leak control configurations were also included in the test protocol.

Model tests
Based on the applications, model tests for controlling pipeline leaks and concrete repair – two schematics and the real models are shown in Fig. 5 – are proposed in the test protocol approved by the United States Environmental Protection Agency.
(http://www.nsf.org/business/water_quality_protection_center/pdf/WQPC_Gro...).

Model Test-3 (Fig. 5a) is used to investigate the effectiveness of grouting and comparable technologies to reduce the leak at the laterals. Model Test-4 is used to evaluate the effectiveness of grouts and other technologies to reduce the leak through cracked concrete. At present, several grouts are being tested under the ETV program using the grout test protocols.

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Schematic of lateral repair Model-3 test

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Fig. 5a: Model-3 test – lateral repair

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Schematic of Model Test-4 – concrete leak repair

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Fig. 5b: Model 4 – test for concrete repair

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