ASTM International C15 Committee on Manufactured Masonry Units’ new standard, C1782/C1782M, Specification for Utility Segmental Concrete Paving Slabs, determines the minimum flexural strength, dimensional tolerances, and freeze-thaw durability requirements for 12- to 48-in. square products.
“There have been some notable paving slab failures over the years in part due to poor pavement design and lack of product standards,” says C15 member and Interlocking Concrete Pavement Institute Technical Director David Smith. “C1782 provides a baseline acceptance standard using any of three manufacturing processes: dry cast, wet cast, and hydraulically pressed.”
“For the first time, paving slab manufacturers, material suppliers, testing labs, and other experts worked together to develop a product standard that addresses the needs of this important paving product group,” adds ICPI Chairman Matt Lynch (Oldcastle Architectural). “Architects, civil engineers, and landscape architects will benefit when writing construction specifications. Paving slab manufacturers will use the standard to promote products that meet or exceed its requirements. The standard will also provide concrete testing labs the opportunity to offer an additional service in testing paving slabs.”
C1782 requirements reflect familiar terms and references for larger paving slabs that do not fall under the existing ASTM C936, Standard Specification for Solid Concrete Interlocking Paving Units. The new standard is for utility slabs and not expressly for high-end architectural units. ASTM C15 will likely see an additional standard or consider amending C1782 to include closer tolerance paving slabs with architectural finishes for roof deck and at-grade applications. Paving slabs represented 13.2 percent of total segmental concrete pavement production in the U.S. and Canada last year, according to the 2016 ICPI Industry Sales Profile, which also noted a 6.3 percent increase in commercial applications for slabs in 2015.
Separately, ASTM E17 Committee on Vehicle – Paving Systems’ proposed WK41917, Practice for Computing Pathway Roughness Index from Longitudinal Profile Measurements standard describes a method to collect and analyze sidewalk slab roughness data. Roughness can make sidewalks uncomfortable and risky for wheelchair and wheeled-walker users, parents pushing strollers and postal carriers with three-wheeled carts, the committee contends.
“The standard and related data collection tools will help establish a new service engineering firms can offer to municipalities and transportation agencies that manage sidewalks and crosswalks,” says E17 member Jonathan Pearlman, co-founder of Pathway Accessibility Solutions Inc. and an assistant professor in the University of Pittsburgh Rehabilitation Science and Technology Department. “For architects and contractors, the proposed standard will help guide design-build approaches for safe and accessible routes.” WK41917 could also be referenced in future Americans with Disabilities Act guidelines, he adds. — ASTM Customer Relations, 877/909-ASTM; www.astm.org
READY MIXED CONCRETE ACCEPTANCE TESTING TOOLS
With Colorado Ready Mixed Concrete Association assistance, the National Ready Mixed Concrete Association Research, Engineering and Standards Committee has produced a checklist and PowerPoint presentation, “Code and Standards Requirements for Acceptance Testing,” covering the purpose of acceptance testing; standard and field curing differentiation; qualification requirements for third-party testing labs and lab and field testing technicians; test report distribution; initial curing requirements for standard cured cylinders for acceptance testing; effect of non-standard testing on concrete strength; responsibilities related to initial curing; reporting of initial curing data; calculating testing variation by test data analysis; and, criteria for core tests and establishing responsibility for low strength evaluations.
Ready mixed concrete personnel, testing labs, plus architects and engineers can use the presentation in local education efforts to help ensure acceptance testing conforms to industry codes and standards. The checklist can be used as a handout in tandem for pre-construction meetings and mixture submittals. NRMCA’s (Technology in Practice) TIP 16 on Evaluating Strength Test Results is likewise a companion to the presentation. Checklist and PowerPoint files can be obtained from NRMCA Vice President, Technical Services Karthik Obla, 240/485-1160; [email protected].