JPS6177685A - Lightweight mortar composition and manufacture of lightweight mortar moldings - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a lightweight mortar composition with controlled setting initiation time and hardening rate, and a method for producing a molded body using this lightweight mortar composition.

[Background of the Invention] In recent years, molded bodies such as panels have been manufactured by injecting lightweight mortar prepared using lightweight aggregate such as synthetic resin foam into a formwork and hardening it within the formwork. This is increasingly being used as a building material for partitions, exterior walls, etc.

A method for manufacturing such a lightweight mortar molded body is to pour (inject) a lightweight mortar mixture into multiple molds,
Next, a method in which the mold is allowed to stand and harden, or a method in which pouring, curing, and demolding are performed continuously while the mold is moved are generally used. However, in the former case, ordinary lightweight mortar does not harden to the extent that it can be removed from the mold unless it is poured into the mold and left in the mold for more than a day to fully cure. A storage place is required to store the formwork filled with lightweight mortar for a long period of time. In addition, in the latter continuous manufacturing method, considering the time it takes for the lightweight mortar to start setting and reach a hardened state that allows demolding, it is necessary to lengthen the total length of the process or increase the process speed. Need to slow down. However, increasing the total length of the process is disadvantageous because it requires a vast site and equipment, and it is also impractical to reduce the operating speed, so in reality, lightweight mortar compositions are In other words, as long as a normal lightweight mortar composition is used, continuous production of lightweight mortar molded bodies is actually not possible. It was impossible.

Therefore, we added a hardening accelerator mainly composed of calcium chloride to the lightweight mortar used for manufacturing such molded bodies, especially continuous molded bodies, to quickly develop the strength necessary for demolding. A method is used to do so. By adding this curing accelerator, the time from pouring to curing to the extent that demolding is possible is shortened to some extent, but the curing accelerating effect is insufficient with the normal addition amount, and it still takes a long time. The strength required for demolding will not develop until later.In order to improve the curing accelerating effect, it is possible to increase the amount of curing accelerator added, but by increasing the amount of curing accelerator added, The final strength of the resulting molded product will be reduced, and when using a metal formwork or manufacturing a molded product with embedded reinforcing bars, use of chlorides as the main component as mentioned above Addition of a large amount of hardening accelerator may cause rusting of the formwork or reinforcing bars.

For the above reasons, light curing using a curing accelerator is recommended. It is difficult to obtain satisfactory results in accelerating the hardening of 1Y mortar.

Another known method is a curing method in which lightweight mortar poured into a mold is brought into contact with water vapor or warm air at temperatures below 100"C to develop strength at 75 degrees. However, even with this method, the mold can be removed. It takes a considerable amount of time to develop the necessary strength.

Additionally, attempts have been made to add an accelerating agent such as water glass to the above-mentioned lightweight mortar. Addition of an quick-setting agent is an effective means for developing strength quickly, but on the other hand, there is a problem in that the time from the addition of the quick-setting agent to hardening is extremely short. In other words, the mortar mixture remains in a state of low viscosity and high fluidity until the mortar mixture is poured into the mold and the surface of the mortar mixture is smoothed using a plastering trowel, a ruler, etc. However, since a mortar mixture with an accelerating agent added starts to harden in a short time, it is difficult to produce a lightweight mortar molded body with internal uniformity and surface condition from such a mortar mixture. difficult to do.

In other words, the lightweight mortar used in the mold manufacturing method using a mold exhibits good fluidity during pouring, and after pouring is completed and a smooth surface is obtained, setting and hardening proceeds rapidly. It is preferable that the time required to reach complete curing is short.

[Object of the Invention] An object of the present invention is to provide a lightweight mortar composition in which setting start time and curing speed are adjusted to Xgl.

The present invention is a lightweight mortar composition particularly suitable for use in a method for manufacturing a molded body by injection into a mold, which exhibits high fluidity during injection into the mold and during the formation of a smooth surface. The object of the present invention is to provide a lightweight mortar composition that rapidly sets and hardens thereafter.

Another object of the present invention is to provide a lightweight mortar composition suitable for use in a method for producing a lightweight mortar molded article that is carried out continuously from injection to demolding.

In addition, the present invention provides a method for producing a lightweight mortar molded body, which uses a mortar composition that can control the setting start time and hardening rate, and allows the demolding time to be set at any time. The purpose is also to provide.

[Summary of the Invention] The present invention provides cement and
The aqueous mixture with 5 times the amount of synthetic resin foam particles contains an accelerating agent and a setting retarder in the range of 2 to 10% by weight and 0.1 to 3% by weight, respectively, based on the cement. A lightweight mortar composition with controlled setting start time and hardening speed.

Furthermore, the present invention provides a method for manufacturing a lightweight mortar molded body by injecting a lightweight mortar composition containing cement and 1 synthetic resin foam particle into a mold, in which the volume ratio of cement to cement is 1 to 5. A light mortar composition containing an aqueous mixture with twice the amount of synthetic resin foam particles is added with an accelerating agent and a setting retarder in the range of 2 to 10% by weight and 001 to 3% by weight, respectively, based on the cement. By containing.

The present invention provides a method for producing a lightweight mortar molded article, which is characterized in that the setting start time and hardening speed of the lightweight mortar composition are adjusted so that demolding is possible at a desired time.

That is, the present invention is characterized in that additives having mutually contradictory properties, ie, an accelerating agent and a setting retarder, are blended into a lightweight mortar composition within a specific blending amount. studies have shown that these additives do not act to negate each other's effects in lightweight mortar compositions. That is, in the lightweight mortar composition of the present invention, the quick setting agent does not show any substantial effect until the mortar begins to set, whereas the setting agent merely increases the time until the mortar starts setting. Therefore, when the lightweight mortar composition of the present invention is used in a molding operation using a formwork, the curing speed after the onset of setting is controlled. Since the time required to set the mortar can be adjusted appropriately, processes such as pouring the mortar mixture and smoothing the surface can be carried out over a sufficient amount of time. , because setting and hardening progresses rapidly.
Demolding is possible in a short time. Therefore, continuous production of lightweight mortar molded bodies is possible, and the strength and surface condition of the resulting molded bodies are at the same level as conventional molded bodies manufactured over a long period of time.

[Detailed Description of the Invention] In the present invention, the cement is not particularly limited and any commonly used cement can be used. Examples of cement that can be used include ordinary Portland cement, early strength Portland cement, blast furnace cement, and fried cement. Examples include ash cement.

The lightweight mortar composition of the present invention needs to contain synthetic resin foam particles in an amount of 1 to 5 times the volume of the above cement.

There are no particular limitations on the synthetic resin foam particles used, and examples of the synthetic resin foam particles used include foamed polystyrene particles and foamed polyurethane particles. Although there is no particular restriction on the particle size, those having an average particle size of 10 mm or less, usually in the range of 2 to 5 mm, are used.

The amount of synthetic resin foam particles added must be 1 to 5 times the amount of cement used. If the amount is less than 1 times, the weight per unit volume of the mortar becomes heavy, making it impossible to obtain the desired lightweight mortar molded product.On the other hand, if the amount is more than 5 times, the synthetic resin foam particles in the mortar will separate. This is undesirable because it is easy to form a molded product and the strength such as the compressive strength of the obtained molded product decreases.

The lightweight mortar composition of the present invention includes an aqueous mixture obtained by adding water to the cement and synthetic resin foam particles and kneading the mixture, and adding an accelerating agent and a setting retarder to the cement. It is necessary that the content be in the range of 1% by weight and 0.1 to 3% by weight.

The water/cement (ball amount) ratio can be appropriately determined depending on the amounts of the synthetic resin foam particles, quick-setting agent, setting retarder, etc. used, but is generally 30-70%1. Usually 35-70%.
It is 65%.

The lightweight mortar composition of the present invention requires that the above-mentioned aqueous kneaded product contain both an accelerating agent and a setting retarder.

As the quick-setting agent, any commonly used one can be used without particular limitation. Examples of quick-setting agents that can be used include sodium aluminate, sodium silicate, sodium carbonate, calcium aluminate, calcined alumite, etc., which can be used alone or in mixtures. . It is particularly preferable to use a quick-setting agent containing sodium aluminate as a main component.

The quick-setting agent must be contained in the aqueous mixture in an amount of 2 to 10% by weight based on the cement6. It is particularly preferable that there be.

If the amount of the accelerating agent is less than 2% by weight, the curing accelerating effect will not be sufficiently exerted, and it will take a long time from the start of setting to demolding, which is not preferable. If the amount of the quick-setting agent is more than 10% by weight, the lightweight mortar poured into the mold will lose its fluidity before reaching the corners of the mold, making it impossible to obtain the desired molded product. This is not desirable because it may disappear. In such cases, it is possible to add an excess of setting retarder to secure the necessary time for the work, but adding too much setting retarder increases the product cost of the resulting molded product. Not only this, but also the physical properties such as the strength of the molded article may be adversely affected, which is undesirable.

Any commonly used setting retarder can also be used without particular limitation. Examples of set retarders that can be used include oxycarboxylic acids such as citric acid and gluconic acid, salts thereof, and lignin sulfonates, which may be used alone or in combination. can. Particular preference is given to using citric acid as set retarder.

It is necessary that the setting retarder is contained in the aqueous kneaded product in an amount of 0.1 to 3% based on the cement. The content of setting retarder is 0.3 to 2% by weight.
It is particularly preferable that the range is within the range of .

If the amount of the setting retarder is less than 0.1% by weight, the setting retarding effect will be insufficient, and setting will start in a short period of time after the addition of the setting retarder and reach a hardened state. By securing the time you need for your work! ! There was no
Alternatively, the effect of the setting retarder may be insufficient, and the effect of the quick-setting agent may not be uniformly manifested, causing the lightweight mortar to partially set quickly. Furthermore, the lightweight mortar injected into the mold loses its fluidity before reaching the corners of the mold, making it impossible to obtain the desired molded body, which is undesirable. Furthermore, when the amount of the setting agent added is 3% by weight or more, the effect of adding the quick setting agent becomes less apparent. However, although it is possible to shorten the setting start time by adding an excessive amount of accelerating agent to delay the setting start time due to the addition of an excessive amount of setting retarder, adding such an excessive amount
This is not preferable because it not only increases the product cost of the resulting molded product but also adversely affects the physical properties such as strength of the molded product.

According to the present invention, by incorporating both an accelerating agent and a setting retarder, which have essentially opposite effects, into a lightweight mortar composition, the setting start time and hardening speed of the mortar composition can be arbitrarily adjusted. can do. That is, in a lightweight mortar composition containing both an accelerating agent and a setting retarder, the time from when the accelerating agent is added to when setting starts is controlled by the action of the setting retarder. After the setting starts, hardening is achieved within a short period of time due to the action of the quick setting agent. Therefore, by adjusting the amount of the setting retarder added, it is possible to adjust the time from the addition of the accelerant to the start of setting, that is, the time required to have fluidity that can be poured into the mold, to any desired time. Furthermore, by adjusting the amount of the quick setting agent added, it is possible to control the curing rate, that is, the state of curing after a predetermined period of time after the start of setting.

For the above reasons, in the method of manufacturing a molded article by injecting and hardening a lightweight mortar composition into a mold, it is possible to use a combination of both an quick-setting agent and a setting retarder in a certain range according to the present invention. It becomes possible to freely control the time (pot life) from the addition of the quick-setting agent to the injection of lightweight mortar until it hardens to the extent necessary for demolding.

The lightweight mortar composition of the present invention contains the aforementioned cement, synthetic resin foam particles, quick-setting agents, setting retarders and other ingredients such as commonly used additives, aggregates, even non-human ingredients. may be added as appropriate to the extent that it does not contradict the purpose of the lightweight mortar composition of the present invention.

Examples of other ingredients used include a dispersant for synthetic resin foam particles consisting of a bituminous substance, a surfactant mainly consisting of a formaldehyde condensate of sodium naphthalene sulfonate, and an anti-caking agent such as diatomaceous earth. can be mentioned.

In the present invention, "setting start time" refers to the time from when the quick-setting agent is added to the aqueous mixture, or from the time when water is added to the cement composition mixed with the quick-setting agent to mix the light mortar. The time from when the composition starts to coagulate until it starts to lose its fluidity, and is called the "demolition period".
This means that the strength of the lightweight mortar composition poured into the formwork is developed to the extent that the demolded molded body can maintain its own shape, that is, it can resist some external force. "Pot life" refers to the period when the surface of the molded product is fluid enough to be smoothed with a plastering trowel, so-called "leveling", immediately after stress molding. This refers to the time from when is added to the time when demolding is possible.

Moreover, "curing speed" refers to the curing speed from the time when setting starts to the time when the curing state reaches a degree necessary for demolding.

The method for producing a molded article using the lightweight mortar composition of the present invention is carried out in a conventional manner.

The above-mentioned cement, synthetic resin foam particles in an amount of 1 to 5 times the volume of the cement, and an accelerating agent and setting agent in the range of 2 to 1 Offiffi% and 0.1 to 3% by weight, respectively, relative to the cement. A lightweight mortar composition containing a retarder is prepared.

Although there are no particular restrictions on the method for preparing the lightweight mortar composition,
Examples of preparation methods include: (a) While rotating a cement mixer into which a set retarder aqueous solution obtained by dissolving a set retarder in a predetermined amount of water is injected, synthetic resin foam particles and cement are added to the mixer. A method in which the mixture is added in sequence and kneaded, and when the whole is homogeneous, an accelerating agent is added and kneaded; Examples include a method in which a mixture and water are put into a cement mixer and kneaded.

In the present invention, it is preferable to prepare by method (a) because the setting start time can be easily controlled.

When preparing a lightweight mortar composition, take into account, for example, the shape and volume of the molded object to be manufactured, or the time allotted for curing to a degree that allows demolding during the manufacturing process, etc. The amount of setting retarder and accelerating agent added should be adjusted so that the material has appropriate fluidity and does not start setting until the end of injection, and that setting starts immediately after injection and leads to hardening. . The amount to be added can be easily determined by preliminary tests.

By adjusting the setting start time and hardening speed in this way, the time when the mold can be demolded can be set to any desired time.
It is preferable to adjust the time from the time of addition of the quick-setting agent to the time when demolding is possible (Ell waiting time) to an arbitrary time in the range of 2 to 60 minutes.

The lightweight mortar composition whose demolding time has been adjusted by controlling the setting start time and hardening rate in this manner is poured into a mold, and is demolded after a predetermined period of time has elapsed. Immediately after demolding, the molded product usually has self-shape retention, that is, has enough self-shape retention to resist some external force, and is hardened to the extent that it can be leveled with a plastering trowel, for example. It is in.

Such a demolded molded body is usually partially repaired and then cured by a conventional method until it is completely cured.

The lightweight mortar composition of the present invention can be used for manufacturing molded objects that need to be demolded from the mold in a short period of time, for example, because the demolding time can be arbitrarily set. It can be used in manufacturing methods such as mass-producing molded objects such as panels by pouring. In addition, in the manufacturing process of molded bodies on a line, lightweight mortar compositions with different amounts of quick-setting agents and setting retarders are prepared to provide unique usability to formworks of different shapes or capacities. By pouring a lightweight mortar composition with a certain composition over time, molded bodies of different shapes or capacities can be taken out in substantially the same cured state at the end of the production line. Furthermore, in a production process where the production process is not organized into a production line, when a molded body is obtained by pouring a lightweight mortar composition into molds of different capacities or shapes, it is necessary to Prepare a mortar composition, pour this lightweight mortar composition into molds at different times, and after a certain period of time, demold them at the same time so that the molded bodies with different curing times have almost the same hardening state. You can also do it.

Next, Examples and Comparative Examples of the present invention will be shown.

Note that tests on lightweight mortar and molded bodies of the mortar were conducted in the following manner.

(1) Unit volume weight J I 5-A-1116 (2
) Pot life - After adding the quick-setting agent using method (a) above, take a sample and perform a feel test with a plastering trowel to determine the usable time that can be leveled with a trowel from the time the quick-setting agent is added. It was time.

(3) Compressive strength JIS-A-1132 and JIS
-A-1108. However, when molding the specimen, no stick was used, but the surrounding formwork was struck 20 times with a wooden hammer to spread the lightweight mortar composition throughout the formwork. The compressive strength of the specimens was measured using specimens aged 3 hours and 7 days after addition of the quick-setting agent.

In addition, as a dispersant for synthetic resin foam particles, sodium naphthalene sulfonate Q formaldehyde condensate 62% by weight, sodium polycarboxylate 6%, bituminous substance 1
A dispersant consisting of 3% by weight and 19% by weight of diatomaceous earth (
Lyconide (manufactured by Ube Industries, Ltd., trade name: Lyconide) was used in an amount of 0.85% by weight based on the cement used.

[Example 1] Into a cement mixer, expanded polystyrene particles (average particle diameter 3 mm) twice the volume of the cement used were charged, followed by a predetermined amount of lyconide and 0.3% of the cement. of citric acid was dissolved in 4Ofi amount of water based on the cement used, and put into a dispersion state into the above-mentioned cement mixer, and a mixing operation was performed.

Ordinary Portland cement was put into the above cement mixer and kneaded until the whole was homogeneous.

After the whole is homogeneous, add 3% by weight of sodium aluminate quick-setting agent (manufactured by Hozolis Bussan ■, product name: QP500L) to the cement, and knead until the quick-setting agent is dispersed throughout. A lightweight mortar composition (kneaded material) was obtained.

Table 1 shows the weight and pot life per unit volume of the lightweight mortar composition obtained, and the compressive strength at 3 hours and 7 days of age of the molded body produced using this lightweight mortar composition.

In addition, when the above-mentioned lightweight mortar composition was poured into a mold and removed from the mold after 2 hours to produce a specimen, the mold was observed to be in a good hardened state, and no deformation of the shape was observed.

[Example 2] A lightweight mortar composition was obtained in the same manner as in Example 1 except that the amount of the quick-setting agent used was 4% by weight.

Table 1 shows the weight per unit volume and pot life of the light-weight mortar composition and the compressive strength at 3 hours and 7 days of age of the molded body produced using this light-weight mortar composition.

In addition, when the above-mentioned lightweight mortar composition was poured into a mold for the production of a specimen, the mold was removed after 2 hours, and observed, the hardening state was good and no deformation of the shape was observed.

[Example 3] A lightweight mortar composition was obtained in the same manner as in Example 2 except that the amount of the setting retarder used was 0.9% by weight.

Table 1 shows the weight and pot life per unit volume of the lightweight mortar composition obtained, and the compressive strength at 3 hours and 7 days of age of the molded body produced using this lightweight mortar composition.

In addition, when the above-mentioned lightweight mortar composition was poured into a mold for the production of a specimen, the mold was removed after 2 hours, and observed, the hardening state was good and no deformation of the shape was observed.

[Example 4] A lightweight mortar composition was obtained in the same manner as in Example 2, except that the amount of anti-caking agent used was 1.5 fi%.

Table 1 shows the weight and pot life per unit volume of the lightweight mortar composition obtained, and the compressive strength at 3 hours and 7 days of age of the molded body produced using this lightweight mortar composition.

In addition, when the above-mentioned lightweight mortar composition was poured into a mold for the production of a specimen, the mold was removed after 2 hours, and observed, the hardening state was good and no deformation of the shape was observed.

[Example 5] A lightweight mortar composition was obtained in the same manner as in Example 1, except that the amount of the anti-caking agent used was 1.5% by weight, and the amount of the quick-setting agent was 7% by weight.

Table 1 shows the weight and pot life per unit volume of the lightweight mortar composition obtained, and the compressive strength at 3 hours and 7 days of age of the molded body produced using this lightweight mortar composition.

In addition, when the above-mentioned lightweight mortar composition was poured into a mold for the production of a specimen, the mold was removed after 2 hours, and observed, the hardening state was good and no deformation of the shape was observed.

[Example 6] A lightweight mortar composition was obtained in the same manner as in Example 4, except that the amount of expanded polystyrene particles used was four times the volume of cement.

Table 1 shows the weight and pot life per unit volume of the lightweight mortar composition obtained, and the compressive strength at 3 hours and 7 days of age of the molded body produced using this lightweight mortar composition.

In addition, when the above-mentioned lightweight mortar composition was poured into a mold for the production of a specimen, the mold was removed after 2 hours, and observed, the hardening state was good and no deformation of the shape was observed.

[Comparative Example 1] A lightweight mortar composition was obtained in the same manner as in Example 1 except that the amount of the quick-setting agent used was 1% by weight.

Table 1 shows the weight per unit volume and pot life of the lightweight mortar composition obtained, as well as the compressive strength at 7 days of age of the molded article produced using this lightweight mortar composition.

In order to produce a specimen, the above-mentioned lightweight mortar composition was poured into a mold and removed from the mold after 2 hours, but the solidification and hardening were incomplete and deformation was observed upon removal from the mold. Also,
It was not possible to measure the compressive strength of the specimen aged 3 hours due to insufficient curing.

[Comparative Example 2] A lightweight mortar composition was obtained in the same manner as in Example 1 except that no setting retarder was used.

Table 1 shows the amount per unit volume and pot life of the lightweight mortar composition obtained.

In addition, since the lightweight mortar hardened rapidly, it was not possible to separate the mortar for molding the specimen.

Therefore, it was not possible to measure compressive strength.

Table 1 with margin below Unit volume weight Pot life Compressive strength (kg/l (min) -〇''l 2 hours 7
Day example 1 0.883 30 2.71 3
1.12 0.705 3 2.93 3
5.33 0.708 B 4.35
35.04 0.699 10 4.63
31.55 0.712 4 6.27
3B, 86 0.48? 12 3.0
3 21.8 Comparative Example 1 0.891 3 hr or more - 7,4520,88 fl Rapid setting -- As is clear from the comparison between Example 1 and Comparative Example 1 above, the lightweight mortar composition of the present invention By using a combination of a binder and a setting retarder within a certain range, the setting start time and demolding time can be controlled within a desired range. That is, in Comparative Example 1, the setting retardant was blended within a preferable range, but since the amount of the quick setting agent was small, the setting start time of the lightweight mortar composition was lengthened.
Therefore, it is unsuitable for use in the production of continuous molded bodies.

Furthermore, a composition lacking either an accelerating agent or a setting retarder cannot achieve the object of the present invention. For example, as shown in Comparative Example 2, a composition lacking a setting retarder has a setting start time of Unable to use a short trowel.

Although the lightweight mortar composition of the present invention contains an accelerating agent and a setting retarder, which have completely opposite effects, as is clear from the above examples, the compressive strength of the molded article is 3.
Even when the wood is aged for several hours, it is approximately 3 kg/cm'' or more, and it is the lowest for wood that is 7 days old (Example 6)
However, the strength was 21.6 kg/ctn', and in Example 5, the strength was 36.8 kg/ctn'. i! It is clear that the co-compounding agent of the spreading agent does not have any adverse effect on the original properties such as the strength of the molded article.

Furthermore, the compressive strength of Examples 1 to 6 and the material age 7 of Comparative Example 1
As is clear from the comparison of the compressive strengths of 1 to 4 days, in Comparative Example 1, which has a small amount of quick setting agent, the curing speed is slow, and the subsequent curing speed until complete curing is also slow, so the compressive strength is sufficient. In addition, the lightweight mortar composition of the present invention has a fast curing speed due to the action of the quick setting agent.
Furthermore, after this, it quickly reaches a completely hardened state and develops strength, so it has the advantage that it does not require long-term curing.

Claims (1)

[Scope of Claims] 1. An aqueous kneading mixture of cement and synthetic resin foam particles in an amount of 1 to 5 times the volume of the cement contains an accelerating agent and a setting retarder, respectively, in an amount of 2 times the volume of the cement. ~10% by weight and 0
．． A lightweight mortar composition with controlled setting start time and curing speed, characterized in that the content is in the range of 1 to 3% by weight. 2. The lightweight mortar composition according to claim 1, wherein the lightweight mortar composition is a lightweight mortar composition for mold casting. 3. The content of the accelerating agent and the setting retarder is in the range of 3 to 8% by weight and 0.3 to 2% by weight, respectively, based on the cement, claim 1 or The lightweight mortar composition according to item 2. 4. In a method of manufacturing a lightweight mortar molded body by injecting a lightweight mortar composition containing cement and synthetic resin foam particles into a mold, the cement and a synthetic resin in an amount of 1 to 5 times the volume of the cement. A lightweight mortar composition containing an aqueous mix with resin foam particles was added to
By containing an accelerating agent and a setting retarder in the range of ~10% by weight and 0.1 to 3% by weight, the setting start time and hardening speed of the lightweight mortar composition can be adjusted and demolded. 1. A method for producing a lightweight mortar molded article, characterized in that the timing is set at a desired timing. 5. Claim 4, characterized in that the content of the quick setting agent and the setting retarder is within the range of 3 to 8% by weight and 0.3 to 2% by weight, respectively, based on the cement. The method for manufacturing the lightweight mortar molded body described above. 6. The method for producing a lightweight mortar molded body according to claim 4 or 5, wherein the demoldable time is adjusted within a range of 2 to 60 minutes from the time of addition of the quick setting agent. .