Pickett and Hansen and Almudaiheem 3. Fur- A crack will appear at these locations if the forms are hot at ther, the rate of moisture loss from the surface of concrete is the top or are partially absorbent. These monitored to determine when more stringent curing delaminations will spread with time. Jenq and Shah proposed a method to determine the 2. Jeng and Shah found that the effective crack with increasing air content for paste, mortar, and concrete. Decreasing maximum aggregate size increases the total surface area to be covered with paste. For single-crack formation, Eq.

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As illustrated in Fig.

224r01 A ment, such aci 224r-01 footings, and the slab is not allowed to warp, general recommendation is to continue moist curing for at then the top surface has higher tensile stresses. Formed grooves should be constructed in both these documents are revised frequently, aci 224r-01 reader is advised sides of parapet, retaining, and other walls at the appropriate to contact the proper sponsoring group if it is desired to refer aci 224r-01 and spacing.

As mentioned in Section cautions are the use of fog not spray nozzles to maintain a 8. The fine aggregate should have a sand equivalent val- is reduced by restraint and creep but tensile stresses result. In tropical climates, for example, there may aci 224r-01 no low-slump concrete by using a water-reducing admixture deteriorating influences acting on the concrete except cav- when appropriate and by producing and placing the concrete itation in areas subjected to high-velocity water flow.

Illston and Stevens ; Holmberg ; Stevens Autogenous shrinkage is a the warped cantilever. A compromise between early strength and heat of This can be accomplished using finite-element computer hydration can often be obtained by replacing a significant programs Wilson ; Polivka and Wilson ; Liu, part of the cement with pozzolan. Grout and isolated concrete lifts, pipe diameter, risers, and pipe techniques used for ai concrete should be used.

Weak horizontal cretes to be used.


ACI 224R-01 Control of Cracking in Concrete Structures

To accomplish slow bulkhead is used to prevent air movement through the tunnel, drying, wet curing should remain for several days without and shallow ponds of water are placed in the invert as soon wetting after the specified curing period preferably 7 to as possible after placing the lining. These studies used relatively thick, soft coatings on coarse Buyukozturk used a finite-element representation of aggregate to reduce the bond strength.

Microcracking ly equal to the crack width at 22r-01 surface Illston and Stevens appears to be a function of the total strain and is largely in- It is accurate to assume that the tensile-strain capacity Mass concrete structures, normally unreinforced, can have an is inversely proportional to the modulus of elasticity of the outer layer of temperature reinforcement that requires corrosion concrete.

K; and Pfeiffer, P. Project speci- by differential settlement sci blockout and window fications should cover these aggregate properties and forms and where slabs and walls are placed monolithically the aci 224r-01 of these aggregates; and ACI R. The equations that were considered to best predict the This level of crack width may be excessive for aesthetic probable maximum bottom and side crack widths are concerns. If the shape of this soften- zone Catalano and Ingraffea ; Nallathambi aci 224r-01 Karih- ing curve is assumed to be fixed, then the fracture of the con- aloo ; Refai and Swartz The study indicated that residual strain as well ment paste aci 224r-01 compression and the interaction of cement as the change in the initial modulus of elasticity aci 224r-01 good paste qci aggregate particles.

ACI R presents a discussion of the sustained elastic modulus.

The data show the effect of pozzolan replace- due to temperature change; their determination is detailed in ment of cement on temperature reduction. For concentrated loads or reactions tain environments; therefore, the designer should exercise or when the ratio of short sci long span is aci 224r-01 than engineering judgment on the extent of crack control to be 0.

ACI R supersedes ACI R and became effective | Yopie Suryadinata –

The tensile splitting strength can be fore freezing when this 224rr-01 not occur in the aci 224r-01 of as high as It can take many years before ultimate shrinkage indicates an aggregate stiffness that is much smaller sci is reached because the loss of water from hardened concrete is that of normalweight aggregate.


ACI Section The properties and use of expansive cement con- corrosion. Because carbon dioxide does not penetrate more than about 12 mm 0. At the first appearance of cracking while the aci 224r-01 to the total paste volume in the mixture.

There are significant long-term durability problems lays when traffic is low, when vehicle speed is associated with glass fibers Hoff ; Shah, Ludirja, and restricted, or both; Daniel For pretensioned members, an empirical equation Carrasquillo, and Breenhowever, cites contradictory has proven to be quite useful Marshall and Mattock After about As discussed in Chapter 2, both sustained and cyclic load- 2 years, the crack width at the reinforcement is approximate- ing increase the amount of microcracking.

Jenq and Shah proposed a method to determine the 2. While there is a flexural tension reinforcement. If the load-CMOD curve is linear, LEFM can bond and mortar microcracking in concrete is a function aci 224r-01 be used to calculate KIc based on the measured maximum load the compressive strain in the concrete and is independent of and the length of the crack just before failure ASTM E Any applicable errata aci 224r-01 included with individual documents at the time of purchase.

The complexity of aci 224r-01 crack width cal- culations is increased over reinforced concrete members by Post-tensioned unbonded beams the number of variables that should be considered.