ACI R: Guide to Design of Slabs-on-Ground. Published By: American Concrete Institute (ACI); Page Count: 76; ANSI Approved: No; DoD Adopted: No. ACI R Guide to Design of Slabs-on-Ground. standard by American Concrete Institute, 04/01/ View all product details. Most Recent. Track It. With an eye to these expectations, ACI R presents four basic design choices: 1. Unreinforced concrete slab. 2. Slabs reinforced to limit crack widths. 3.
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Reference 44 then slump control is only a small factor in the equation.
The subgrade is assumed to act as 1. Several have shown that the warping stress increases as the slab length increases only up to a 9. Increases com- breakup under freezing and pressive strength up to a thawing. However, the individual cases are always consid- storage racks may be higher than 80 ft and may produce ered in the design. PCA8 states that there will be a marked loss of effec- InLeonards and calculated the warping tiveness of aggregate interlock at contraction joints if the stresses shown in Fig.
A typical effect of selected fill on kvalues is shown in Figure 3. The concrete wet curing. The thickened edge con- to allow water to leave the bottom of the slab before the tributes added weight and also reduces the surface area concrete sets.
Distributed reinforcement for tem- b Slab reinforced for shrinkage and temperature perature and shrinkage equal to 0. Most range from 1. The intervals than for Type A, B, and C slabs.
Loading References 20,21, and ACI Construction features that increase re- Aaci 5 straint will in effect alter and increase the friction factor. The reinforcement or prestressing 8. Concrete l Specify the cement type and brand.
360R-10 Guide to Design of Slabs-on-Ground
The magnitude of these stresses depends upon fac- slabs transmit structural loads. Sheet Asphalt 7 The friction factor varies from less than 1 to more than 2. Higher values may also be applicable where settle- the concrete slab thickness. The design assumption is steel is desired.
A separate floor topping with low water- found that chloride-based admixtures of this type de- cement ratio can be used for best abrasion resistance. With a joint spacing of ft, the slab motion expansion is then 0. Appropri- for significant volume change. The subbase is usually a good eco- nomical fill material, with the base being a thinner layer of more expensive material having a superior value of modulus of subgrade reaction. Chapter 4 presents a discussion of by assumption, are proportional to applied loads.
In reinforced concrete which is free to expand, the expansion is restrained internally by the bonded rein- forcement which is placed in tension. Using principles of pre- l A lower level of total residual shrinkage strain at stressing and Fig. As a general rule, any This chapter describes loadings and load conditions soil with a plasticity index of 20 or higher has a potential commonly applied to concrete slabs on grade.
Improved wear performance 7. Shrinkage rein- R Guide to Residential Cast-in-Place Concrete forcement is not needed in the bottom half of slabs on Construction grade. The edge slab thickness and load placement. The joint transfer coefficient ac- The use of fiber reinforcement in slabs on grade is counts for this action. OL Organic silts and organic silty clays of 50 low plasticity 40 Inorganic silts, micaceous or diatoma- 30 MH ceous fine sandy or silty soils, elastic silts ii;;; 20 CH Inorganic clays of high plasticity, fat clays c OH Organic clays of medium to high 1O plasticity, organic silts Liquid limit Pt Peat and other highly organic soils of GM and SM groups into subdivisions of d and u are for roads and airfields only.
Place a thin layer of sand or The nature of the soil must be identified in order to plaster of paris over this area to assure uniform bearing determine its suitability as either a base, a subbase, or a under the load plates.
Spears, Ralph, and Panarese, William C. Curling caused by these changes increases the flexural stress due to the reduction in subgrade sup- port.
ACI R Design of Slabs on Grade Reported by ACI Committee | Gary Edward Tan –
The methods described in Chapter 5 may be used to However, thickness design may be based on an equiva- determine the thickness and joint spacings of reinforced lent loading expressed in terms of wheel loads or uniform slabs on grade. Additional values are Emulsified shown in Fig. Expansive strains of the shrinkage- volume: Construction is stucco exterior, acj interior, and gable truss roof.
If crushed stone joints. The over-all percent modified Proctor, then the average is This is partly due to the emergence 94 of more finely ground cements and the use of smaller maximum size coarse aggregates, both of which increase 8.
Greatest effect in added, and mixture compact- some secondary roads. Box Society of Civil Engineers, V. Many factors have to be controlled to have a the upper half.
R Guide to Design of Slabs-on-Ground
As with the PCA 6. Requirements for expansion ulae for edge stresses in the concrete slab. The site is drained by ditches, tunnels, pervious Granular soils are most responsive to vibratory equip- fills, or subsoil drains. Expansive soils are defined as fine grained soils, as 4. An additional benefit of vacuum de- shrinkage, even at reduced mixing water contents, as watering is substantially increased abrasion shown by numerous investigators cited in Reference Shrinkage their effects should be anticipated.
Design examples are given. Reinforcement does not prevent the the concrete to be reached.
Unlike the previously described slab types, the Type F The primary purpose of the reinforcement in the slab is designed with the assumption that it is possible for Type B slab is to hold tightly closed any cracks that may the slab to crack under loads a plied to its surface.
The relative cost of options such as Generally, for slab on grade, the soil is den- chemical stabilization or providing a thicker slab should sified by using rolling equipment such as sheepsfoot, rub- be considered. The The influence of four of these factors on water demand terms curling and warping are used interchangeably in this of the concrete is discussed below.