ACI PRC-350.2-2021 Hazardous Material Containment in Concrete Structures—Report.
2.2.4.2 Pavement slabs—Pavement slabs typically capture precipitation and spills of hazardous materials in areas where vehicles or other concentrated loads are anticipated. Pavement slabs can be either prestressed or nonprestressed and designed as plates on elastic foundations. A qualifed geotechnical engineer should determine the properties of the subgrade, including soil classifcation and modulus of subgrade reaction. Acceptable analytical techniques include fnite element, fnite diference, and other techniques that give comparable results. Flexural and punching shear stresses should be used to design the conventional and prestressed reinforcement. Nonprestressed pavement slabs designed for vehicle loads of AASHTO H-10 or heavier should be at least 8 in. (200 mm) thick and should contain two layers of reinforce- ment in each direction. The slab thickness for lighter wheel loads may be according to Section 2.2.4.1. The reinforce- ment percentage should total at least 0.5% of the cross- sectional area in each orthogonal direction, with at least one-half, but not more than two-thirds, of this amount in the upper layer. ACI 350 provides requirements for the design of fexural reinforcement, including the additional “environ- mental durability factor,” where applicable.
2.2.7 Minimum nonprestressed reinforcement for prestressed concrete—The minimum nonprestressed rein- forcement in prestressed concrete containment structures should be 0.15 percent for secondary containment and 0.30 percent for primary containment when movement due to shrinkage is partially restrained, such as slabs-on-ground. It should be the same as recommended for nonprestressed concrete wherever movement due to shrinkage is fully restrained, such as when concrete is placed against and bonded to hardened concrete at a construction joint. 2.2.8 Roofs 2.2.8.1 Joints in roofs—Liquid-tight cast-in-place roofs should be placed without construction joints whenever possible. When joints in cast-in-place roofs are unavoid- able, they should be designed and detailed according to the recommendations of Sections 2.2.5 and 2.2.6. Joints between precast roof members should be designed and detailed for liquid-tightness with requirements provided by ACI 350 and Section 3.2 of this report. 2.2.8.2 Roof design—ACI 350 provides requirements for the design of domes and roof slabs for concrete liquid- containing structures. Roof slabs can be either prestressed or nonprestressed. Acceptable analytical techniques include fnite element, fnite diference, equivalent frame, and other techniques that give comparable results. Flexural and punching shear stresses should be used to design the section thickness and conventional and prestressed reinforcement. Flat nonprestressed roof slabs should be at least 6 in. (150 mm) thick. The reinforcement percentage should total at least 0.5% of the cross-sectional concrete area in each orthogonal direction. ACI 350 provides requirements for the design of fexural reinforcement, including the additional environmental durability coefcient where applicable. Roof slabs should be checked for long-term defection and the potential for ponding.
2.4—Exposure 2.4.1 Freezing and thawing—Refer to ACI 350 for requirements for concrete exposed to freezing and thawing. Also, vapor barriers, liners, or coatings help to prevent the concrete from becoming saturated with moisture. 2.4.2 Harsh service conditions—For harsh service condi- tions, reinforcement cover should be increased and, if necessary, the concrete should be provided with a corrosion protection system. Harsh service conditions include expo- sure of the concrete to chemicals and materials that can either react with or degrade concrete. These service condi- tions include exposure to certain acids and bases and high sulfate content solutions. Coated reinforcement or coated prestressing, stainless steel, or nonmetallic reinforcement should be considered in corrosive chemical applications. When using coated reinforcement, the reduction in bond strength, particularly as it may afect cracking, should be taken into account. Using a greater number of smaller diam- eter bars or a higher percentage of reinforcement (a higher reinforcing ratio) will reduce these efects. Refer to ACI 201.2R for other durability considerations. Aggressive concrete exposure conditions may warrant development of provisions for a corrosion protection system, such as a coating or liner. The corrosion-protection system should provide not only corrosion protection but, to the maximum extent possible, the fexibility to span or stretch over cracks and accommodate the movement the concrete will experience. Refer to ACI 350 Chapter 4 and ACI 515.2R.ACI PRC-350.2 pdf download.