Pdf concrete steam curing under atmospheric pressure provides moisture and increases the temperature up to 100 o c for accelerating the. The curing of concrete elements by diffusing carbondioxide into it under controlled pressure and temperature is one of the popular methods of accelerated curing. Effect of curing methods on density and compressive. How to cure concrete by steam curing at high pressure. Curing precast concrete by steam curing method engineering. Different type of curing methods in concrete construction. This procedure is adopted at a precast concrete plant where the concrete members are massproduced. Four of the beams were moist cured at room temperature. Live lowpressure steam curing, in tandem with tarping or covering see figure 1 is a. The steam curing for precast concrete products often produce a lot of them in a short period of time 14. Materials subjected to this hardening technique tend to cure more uniformly and also much more quickly than those hardened via other processes. Steam curing of concrete is the method of curing the concrete elements in water vapor.
Figure 1 shows an example of temperature hysteresis of steam curing. The first one is steam curing at ordinary pressure, while the other is done at a high pressure. Traditionally, precast plants have relied on boiler heating systems for curing concrete. While these oil and gasfired systems were once the only practical means available to accelerate curing, they have many inherent disadvantages. For this purpose, a concrete mixture of m 40 grade with watercement ratio 0. Studies related to steam curing of concrete have been oriented toward the development of compressive strength 36, pore structure development 79 and energetic efficiency of this process 5,10. Usually, the formwork of its production is once in a day. Paving stones, segment walls, semi dry concrete paving slabs, wet cast concrete paving slabs, prestressed concrete products, roof tiles.
Page of 7 curing of ncreteco n curing by preventing excessive loss of moisture from the concrete. Steam curing is curing in water vapor at atmospheric or higher pressures. Steam curing of concrete at atmospheric pressure has the advantage of accelerating the hydration reactions of portland cement. The various methods of steam curing are briefly described and preliminary laboratory data on the effect of low pressure curing are given. It can be used in cold weather conditions for rapid hardening of concrete by this method high early age strength is achieved in concrete speedy. This method is mostly adopted for prefabricated concrete elements. January 19, 2021 steam curing is a process for hardening concrete, cement, and mortar that involves exposure to warm steam. In steam curing, there are two arrangements for the curing of concrete. The factorial design approach was used in this investigation as a. This curing is performed either under atmospheric pressure or highpressure steam. Curing may be applied in a number of ways and the most appropriate means of curing may be dictated by the site or the construction method. The gain of earlyage compressive strength in steamcured concrete is affected by mixture composition and curing parameters. Steam curing steam curing and hot water curing is sometimes adopted. Time between mixing of the concrete and beginning of steam curing delay t.
The process lets the co2 to diffuse into the concrete and undergo carbonation. Steam curing this method is useful in cold weather or when early strength gain is important. The technology of steam curing has been primarily employed for pure cement concrete rather than concrete with a large portion of mineral admixtures as many researchers and housing developers have expressed their concern that the early compressive strength of concrete with a large portion of mineral admixtures is low 1618, which make it. Steam curing is used where early strength gain is needed and where heat is. It has been found that the curing system greatly influences the concrete strength. Thermal damage and its controlling methods of high. Steam curing is a process for hardening concrete, cement, mortar that involves exposure to warm steam. Steam curing is advantageous where early strength gain in concrete is important. They range from the most popular watersubmerged curing to moist sand, waterspray curing, polythene membrane sealing and steam curing autoclaving. As mentioned previously, unlike steam curing of conventional concrete with a typical watertocement ratio of 0.
These techniques are especially useful in the prefabrication industry, wherein high early age strength enables the removal of the formwork within 24 hours, thereby reducing the cycle time, resulting in costsaving benefits. Due to the significant variations in conditions between the plant setting and the laboratory. In the precast concrete industry, steam curing allows increased production by a more rapid turnover of molds and formwork. The concrete mixtures were produced using portland cement cem i 52. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed. Methods that accelerate strength gain by supplying heat and additional moisture to the concrete. In ordinary pressure steam curing, a tarpaulin or pvc sheet is used to form the enclosed area around the concrete component that needs to be cured.
The steam heated concrete process can be used during the winter months to help standardize the production curing cycle on a. Steam curing of concrete magazine of concrete research. Us2880101a us58745756a us2880101a us 2880101 a us2880101 a us 2880101a us 58745756 a us58745756 a us 58745756a us 2880101 a us2880101 a us 2880101a authority us united states prior art keywords concrete steam weight mixture magnesia prior art date 19560528 legal status the legal status is an assumption and is not a legal conclusion. Conventional curing involves the continuous saturation of the concrete surface with water for a specified length of time, starting as soon as the concrete is no longer susceptible to damage at ambient temperatures. Optimization of steamcuring regime for highstrength, self. Effects of curing methods of concrete after steam curing. Steam curing is a process for hardening concrete, cement, and mortar that involves exposure to warm steam. Us2880101a manufacture of steamcured lightweight concrete. The need for adequate curing of concrete cannot be overemphasized. The steam curing method is preferred where there is a need for accelerated strength gain and the concrete requires additional heat to perform hydration. Pdf carbonation curing versus steam curing for precast.
Steam curing effect on the properties of fly ash high. This curing is performed either under atmospheric pressure or. Curing is the maintenance of a satisfactory moisture content and temperature in concrete for a period of time immediately following placing and finishing so that the desired properties may develop fig. This is usually accomplished with live steam, heating coils, or electrically heated forms or pads. If you do curing of concrete for a longer time, there are more chances of a better strength of the structure andcontinue reading the cure for concrete answer key staar. Another method of curing is to cover the wetted concrete surface by a layer of water proof material, which is kept in contact with the concrete surface of seven days.
Steam curing of portland cement concrete at atmospheric pressure. Consequently, the material develops compressive strength and reduces its permeability in a shorter time compared with standard curing under ambient conditions. Precast concrete structure cured with steam shall not be removed from the forms for at least 48 hours after the concrete has been poured. Irjetinternational research journal of engineering and.
Effect of steam curing on the important properties of concrete. Accelerated curing is any method by which high early age strength is achieved in concrete. May 28, 2010 conventional live steam curing systems utilize curing cells kilns that are either concrete structures or curing canopies made from canvas, polyweave, etc. Steam curing of concrete at high pressure manufacture. The gain of earlyage compressive strength in steam cured concrete is affected by mixture composition and curing parameters. When cured at atmospheric pressure, the enclosure temperatures are usually between 40 and 70 c 100 to 160 f. Outline of steam curing steam curing is a method for accelerated curing whereby concrete is cured in hot steam to obtain the required strength early. The block diagrams, shown in figure 1, contrast the typical steam curing process and the proposed carbonation curing method. The highpressure concrete steam curing is different from ordinary steam curing, here the curing is carried out in a closed chamber. In order to obtain maximum control over the steam curing procedure it is necessary to specify limits for the following variables. Steam has heat moisture in it, and it is sprayed on the concrete surface to keep concrete moisture and also increases the concrete temperature, which eventually quickens the pace of hardening concrete. Curing is deemed to have commenced once the temperature in the enclosure has exceeded 500c and must be maintained for a minimum curing period.
Concrete necessary to fabricate one beam was mixed in two separate batches. Effect of steam curing on the strength of concrete by using. Because steam curing of concrete is widely used in the manufacture of precast concrete products, especially concrete pipe, investigations were conducted in the bureau of reclamation laboratories to determine the effect of steam temperatures from 100 to 160 f, length of steam curing from 6 to 48 hr, and of a. This video explains the concept of steam curing of concrete at high pressure. This paper presents a laboratory study on the performance of steam cured. Pdf influence of steam curing cycle on compressive strength of. An approximate method for assessing the effect of a stated cycle of operations is described. The effects of time and temperature, type of aggregate, type of cement and size of specimen are discussed. This video explains the concept of steam curing of concrete at ordinary pressure. Steam mixed concrete can reduce the cycle times normally employed with subsequent curing, and possibly eliminate the usual delay period prior to steam curing. Autoclaved aerated concrete aac is a structural material which is commonly used around europe, particularly as it combines ease of construction with excellent combination of mechanical and thermal properties 1. Our ndg steam generators come with all necessary security devices and the suitable certi. This paper reports the results of work undertaken to evaluate the effect of the steam curing regime on mechanical properties for scc with design compressive strengths of 60 and 80 mpa 8700 and 11,600 psi.
Accepted by cement and concrete composites, 2015, doi. Sep 30, 2020 to reduce the adverse effects of steam curing on concrete, 2 h of pre curing was used at normal temperature 20 c. Steam curing of concrete at high pressure manufacture of. Introduction the steam curing for precast concrete products often produce a lot of them in a short period of time 14. The four trial batches of uhpc were cast at a precast concrete plant in albuquerque, n. Pdf influence of steam curing cycle on compressive. A number of curing techniques can be applied depending on various factors considered on site or due to the construction method. Steam curing of concrete at ordinary pressure manufacture. Effect of steam curing on initial strength development of mortar. Of note is that steam curing consumes energy and releases the resulting co 2.
Steam curing is used where early strength gain is needed and where heat is required for hydration, such as in cold weather. The slump was maintained at approximately 2 incheso steam curing did not start immediately after a beam was cast. Influence of steam curing method on the performance of. Implementing nonproprietary, ultrahighperformance concrete. How to cure concrete by steam curing at atmospheric pressure.
Except for steam curing system, the specimens of which were tested at the age of three days, for all other curing conditions, the compression tests were performed at the age of 28 days. For all prestressed concrete members, curing shall continue from this commencement point until the product of the curing time and enclosure temperature exceeds 4200c hours. Effect of steam curing on initial strength development of. Investigation of the loss of prestress in prestressed. May 31, 2018 steam curing can be used to advantage where early strength gain in concrete is important or where additional heat is required to accomplish hydration, as in coldweather concreting. Methods of curing concrete curing types and techniques.
The superheated steam at high pressure about 80 to 170 psi 5. After pre curing, concrete was placed in a steam curing box for 12 h, which included a 2 h of temperature rising from 20 to 60 c, a treatment at 60 c for 8 h and a cooling within 2 h. Influence of steam curing on compressive strength table 4. An investigation of steam curing pressure effect on. Concrete cannot be subjected to dry heat to accelerate the hydration process as the presence of moisture is also an essential requisite.
This is used for enclosed castinplace structures and large precast units. Pdf influence of steam curing cycle on compressive strength. This method of curing is termed as membrane curing 4. The higher the initial temperature of the curing environment, the lower the ultimate strength. It has been found that the curing system greatly influences the concrete. This series was set up to study the effect of steam curing upon concrete at several ages up to one year. Optimization of steamcuring regime for highstrength. This paper investigates the properties of steam cured recycled aggregate concrete rac, in an attempt to determine the optimum. Curing has a strong influence on the properties of hardened concrete.
Live steam is commonly supplied to the cells through holes in distribution piping or steam hoses attached to steam header lines. Conventional curing and lowpressure steam curing are two of the more common methods of curing precast concrete products. Expired lifetime application number inventor ulfstedt leo torsten. Shows how we cured the concrete after it was poured to help keep it warm. Paving stones, segment walls, semi dry concrete paving slabs, wet cast concrete paving slabs, prestressed concrete. The transfer of the heat from the boiler to the concrete is inefficient.
The temperature within the enclosure shall be between 52c and 65c during the time the steam is being applied and shall not be allowed to drop below 27c while the steam is turned off. The precast concrete product is managed in a factory and is made in good environment. Effect of curing conditions on the performance of precast concrete. Effects of curing methods of concrete after steam curing on. An investigation of steam curing pressure effect on pozzolan. The most commonly adopted curing techniques are steam curing at atmospheric. Time between mixing of the concrete and beginning of steam curing delay. Therefore, subjecting the concrete to higher temperature and maintaining the required wetness can be achieved by subjecting the concrete to steam curing. Apr 2006 data sheet curing of concrete curing is the process of controlling the. The co 2 emissions from co 2 curing of the concrete sample.
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