1、中文 5635 字 外文翻译 一、原文 Discuss the construction temperature and crack of the concrete lightly The summary: In order to prevent the owners of the concrete work of claims, we must do a good job in the construction process in the temperature and crack control, through observation live for many years, thro
2、ugh consulting the monograph about stress within the concrete, explain to concrete temperature reason, on-the-spot concrete control and measure, prevention of crack of temperature that crack produce. Keyword Concrete Temperature stress Crack Control 1. The concrete occupies the important position in
3、 modern engineering construction. But today, the crack of the concrete is comparatively general, the cracks are nearly omnipresent in the science of bridge building. Though we take various kinds of measures in constructing, careful, but the crack still occurs now and then. Tracing it to its cause, i
4、t is one of them incompletely that our change to concrete temperature stress pays attention to. In the large volume concrete, temperature stress and temperature control are significant. This is mainly because of the reason of two respects. First of all, concrete often appear the temperature crack in
5、 not constructing, influence the globality and durability of the structure. Secondly, in the course of operating, the temperature change has remarkable influence that cant be ignored on the stress state of the structure. We meet to construct temperature crack in mainly, so only to origin cause of fo
6、rmation and treatment measure, concrete of crack make a discussion in constructing this text. Reason of a crack It has many kinds of reasons to produce the crack in the concrete, it is mainly the changes of temperature and humidity, fragility and disparity of the concrete, and the structure is unrea
7、sonable, the raw materials is not up to standard (if the alkali aggregate react), the template is out of shape, the foundation does not subside etc. evenly. The cement emits a large amount of heat of hydration when the concrete is hardened, inside temperature is rising constantly, cause the stress o
8、f drawing on the surface. In the course of lowering the temperature, is it congeal foundation pay restrain to mix always later stage, will present the stress of drawing within the concrete. Reducing of temperature can surface cause heavy stress of drawing very in concrete too. When these draw the st
9、ress and go beyond resisting the ability of splitting of concrete, namely will present the crack. A lot of inside humidity of concrete change very light or change relatively slow, surface humidity might change heavy the violent change takes placing. Such as maintaining thoroughly, when getting wette
10、r when not doing, contract surface there arent deformation doing, often cause the crack too. The concrete is a kind of fragility material, tensile strength is about 1/10 of the compression strength, is it carry on ones shoulder or back limit when draw out of shape to have（ 0.6 1.0）104 only, is it ca
11、rry on ones shoulder or back limit location when stretch out of shape to there is（ 1.2 2.0） 104 to add for a long time to add a short time. Because raw materials even, water dust than unstable, transport and build phenomenon of emanating of course, its tensile strength is not even in the same concre
12、te, a lot of resist the ability of drawing very low, it is apt to present the weak position of the crack. Among armored concrete, draw stress to undertake by reinforcing bar mainly, concrete bear stress of keeping just. Or reinforcing bar mix if edge position gone to congeal presents the stress of d
13、rawing in the structure in plain concrete must rely on the concrete oneself to bear. Require avoiding the stress of drawing or only very small stress of drawing appears of the general design. But the concrete is cooled from maximum temperature to the steady temperature of operating period in constru
14、cting, often cause sizable to draw the stress within the concrete. The temperature stress can exceed other outsides and load the stresses caused sometimes, know change law, temperature of stress for carry on reasonable structural design and construct extremely important. Analysis of 2 temperature st
15、resses It can be divided into following three stages according to the forming process of the temperature stress: (1)It is early: It needs generally 30 day from beginning building concrete to finishing sending out heat basically by cement. There are two characteristics at this stage, first, the cemen
16、t emits a large amount of heat of hydration, second, mix and congeal the changing sharply of elastic model quantity. Because of the change of elastic model quantity, form the remaining stress in the concrete in this period. (2)Middle period: Up till the concrete is cooled until stability temperature
17、 from cement send out heat function basically when expiring, in this period, the temperature stress is mainly because the cooling of the concrete and external temperature change cause, these stresses and remnants stresses that is formed in early days are superposed, mix and congeal the elastic mould
18、 amount that goes to and does not change much during this period. (3)Later period: Operation period after the complete cooling of concrete. Temperature stress whether external temperature change causes mainly, these stresses and first two kinds of remnants stresses are changed and added. It can be d
19、ivided into two kinds according to the reason why the temperature stress causes: (1)Spontaneous stress: There are not any restraints or totally static structure at the border, if inside temperature is non-linear distribution, temperature stress appearing because structure restrains from each other.
20、For example, the body of mound of the bridge, the physical dimension is relatively large, surface temperature is low when the concrete is cooled, inside temperature is high, present the stress of drawing on the surface, present the stress of pressing in the middle. (2)Restrain the stress: All of the
21、 structure ones or it restrain external one some border, cant out of shape and stress not cause not free. Such as case beam roof concrete and guardrail concrete. These two kinds of temperature stresses draw back stresses caused to act on with the doing of concrete together frequently. It is a more c
22、omplicated job to want to analyse the distribution, size of the temperature stress accurately according to known temperature. In case of great majority, need to rely on the model test or the number value to calculate. To is it make temperature stress have sizable limp to creep concrete, at the stres
23、s accounting temperature, must consider the influence that creep, calculate concretely that no longer states thinly here. Control and preventing the measure of the crack of 3 temperature For prevent crack, lighten temperature stress can from control temperature and is it is it set about to restrain
24、terms from two to improve. The measure of controlling temperature is as follows: (1)Is it improve aggregate grade mix, is it do rigid concrete to spend, mix mixture to adopt, is it guide angry pharmaceutical or plastification pharmaceutical, etc. measure in order to reduce cement consumption of conc
25、rete to add； (2)Add water or the water to cool the broken stone in order to reduce the temperature of building of the concrete while mixing and shutting the concrete； (3)Reduce the thickness of building while building the concrete on hot day, utilize and build the aspect to dispel the heat； (4)Bury
26、the water pipe underground in the concrete, enter the cold water to lower the temperature openly； (5)Stipulate rational form removal time, the temperature keeps warm the surface while lowering suddenly, in case that the rapid temperature gradient takes place in the concrete surface； (6)The concrete
27、with medium and long-term and exposed construction builds a piece of surface or thin wall structure, take the measure of keeping warm in cold season； The measure of improving condition of restraining is: (1)Divide and sew and divide one rationally； (2)Prevent the foundation from rising and falling too big； (3)Rational arrangement construction process, prevent the too big discrepancy in
