CN103467048A - Artificial fish reef concrete and preparation method thereof - Google Patents

Abstract

The invention relates to an artificial fish reef concrete and a preparation method thereof. It is prepared from cement, mixing water, fine aggregate, stones and admixtures, wherein the mass ratio of cement: mixing water: fine bones: stones 1:(0.3～0.5):(1～1.8):(2.4～3.4), the artificial fish reef concrete is poured for 12 to 24 hours and then demolished; sky. The artificial fish reef concrete and its preparation method are characterized in that the quick-hardening sulphoaluminate cement is used as the cementitious material, and the Ca(OH) ₂ produced by the cementitious material is less after hydration. This kind of artificial fish reef concrete is maintained by seawater and has excellent performance. In natural sea areas, the pH value of the pore fluid exuded from the surface is close to that of seawater in a short period of time, which is conducive to the attachment and reproduction of marine organisms such as algae and microorganisms. Excellent workability, high strength and high durability.

Description

Artificial fish reef concrete and its preparation method

technical field

The invention belongs to the intersecting field of building materials and marine engineering, and relates to artificial fish reef concrete and a preparation method thereof.

Background technique

The 21st century is "the century of the ocean". All countries will raise the development of marine strategy to an unprecedented strategic height, and the development of marine economy will stand at a new historical starting point. While accelerating the development of the marine economy, the offshore ecological environment and resource constraints will also face further difficulties. It has become an essential trend to develop a system for the restoration and improvement of the marine environment. At present, countries around the world are competing to carry out marine engineering development projects for ecological restoration named after marine ranches.

Among the several methods of marine ranching, the artificial reef is a three-dimensional use of the water body, which has the best effect, and it can increase the production of fish catches. The mechanism of marine ecological restoration of artificial reefs is through the adsorption of algae by artificial reefs, the filter-feeding effect of attached organisms on reefs, the inhibition of red tide triggering factors by the feeding of a large number of organisms in reef areas, and the inhibition of the release of organic matter on the seabed by reefs, etc. Function, reduce the degree of eutrophication of water body, play the role of purifying water quality and reducing the occurrence of red tide. The construction of artificial reefs is of great significance to the restoration and improvement of the ecological environment, the protection and luring of fish, the protection of beaches, and the development of leisure and eco-tourism.

Due to the characteristics of the concrete material itself, it has a series of advantages, and artificial fish reefs with different shapes and specifications, complex structures and beautiful appearance can be prepared. In the development of recent decades, the use of concrete artificial fish reefs has increased trend. In 2010, 500 artificial reefs were launched in Zhuzhou and Hengzhou, Guangdong. During the process of launching, Dongao fishermen declared that the reef area is the "fisherman's bank".

Artificial fish reef concrete will encounter the following problems in the future development: (1) Ordinary Portland cement used in reinforced concrete artificial fish reefs has a high pH value, which is not conducive to algae attachment and growth, and its carbon emissions are high . (2) In order to reduce transportation costs, artificial reefs should be built near the sea, but seaside fresh water and river sand resources are scarce. (3) Salt erosion and biological corrosion in the ocean lead to expansion and deterioration of concrete and corrosion of steel bars, reducing the life of reinforced concrete artificial fish reefs.

In addition, Patent No. 200810241021 discloses low-alkalinity cementitious materials and preparation methods for concrete artificial fish reefs made of fly ash, blast furnace slag, coal gangue, dihydrate gypsum, desulfurized gypsum, iron sulfate, etc. as raw materials. The pH value of the artificial fish reef made by the method is close to that of seawater, and can also achieve higher strength. However, the stability and durability of this cementitious material in the marine environment are unknown.

Patent No. 200910076730 discloses a method for preparing artificial fish reefs with metallurgical slag as the main raw material. This method screens and classifies river sand, and mixes sand with a particle size of less than 5mm with steel slag, slag, and cement clinker in proportion to prepare. Concrete, and high-strength concrete artificial reefs are obtained after high-temperature curing. The pH value of the artificial fish reef prepared by the method is close to that of seawater. However, this method requires high-temperature curing during the preparation process, which is not practical in engineering construction, and its durability is also unknown.

This patent uses fast-hardening sulfoaluminate cement, rust inhibitor, sea sand, sea water and stones as raw materials, and adopts sea water curing to prepare artificial fish reef concrete compatible with marine ecology. Sea sand and seawater are used as raw materials for artificial reef concrete, and seawater is used for curing. The source of raw materials is convenient and economical. In addition, the production energy consumption of sulphoaluminate cement is lower than that of Portland cement, its _CO2 emission is basically half that of Portland cement, its impermeability is more than twice that of Portland cement, and it is alkaline Low, the surface pH exudation value is close to seawater under 28d immersion in seawater. This patent adopts it as the cementitious material of artificial fish reef concrete and has good durability.

Contents of the invention

The object of the present invention is to prepare artificial fish reefs by using quick-hardening sulphoaluminate cement, sea sand, stones, sea water and additives as raw materials. There is no need to use ordinary Portland cement to reduce carbon emissions; in addition, sea sand and seawater can be used to obtain local materials, which reduces costs and saves energy; the artificial fish reef concrete prepared by this method can make concrete fish reef concrete in a short time The pH value of the surface reaches the pH value of seawater, which is conducive to the attachment and growth of aquatic organisms and promotes the restoration of marine ecology.

The technical scheme adopted by the present invention is: an artificial fish reef concrete, which is prepared from cement, mixing water, fine aggregate, stones and admixtures, wherein the mass ratio of cement: mixing water: fine bones: stones It is 1:(0.3～0.5):(1～1.8):(2.4～3.4).

Further, the cement is 42.5 rapid hardening sulfoaluminate cement; the fine aggregate is sea sand; and the mixing water is sea water.

Further, the admixture includes retarder, water reducing agent and triethanolamine.

Further, the content of the retarder is 0.2-0.4% of the cement content; the content of the water reducer is 1-2% of the cement content; the content of the triethanolamine is 1-2% of the cement content .

At the same time, the present invention provides a method for preparing artificial fish reef concrete. The artificial fish reef concrete is prepared from cement, mixing water, fine aggregate, stones and admixtures, wherein cement: mixing water: fine bone : The mass ratio of stones is 1:(0.3～0.5):(1～1.8):(2.4～3.4); after pouring artificial fish reef concrete for 12 to 24 hours, remove the formwork; Carry out seawater conservation for 7 to 28 days.

Further, the cement is 42.5 rapid hardening sulfoaluminate cement; the fine aggregate is sea sand; and the mixing water is sea water.

Further, the admixture includes retarder, water reducing agent and triethanolamine.

Further, the content of the retarder is 0.2-0.4% of the cement content; the content of the water reducer is 1-2% of the cement content; the content of the triethanolamine is 1-2% of the cement content .

Further, the concrete pouring time of the artificial fish reef is 24 hours.

Further, the seawater curing of the artificial reef concrete is 28 days.

The advantages of the present invention are as follows:

(1) Using rapid-hardening sulfoaluminate cement as the cementitious material, the carbon emission is reduced by half compared with ordinary Portland cement, and the cost is also lower than that of ordinary Portland cement. The pH value reaches 80%, and the pores are relatively dense, which is conducive to seawater conservation; the low pH value can improve the living environment of aquatic organisms around fish reefs.

(2) Using sea sand and seawater as a mixture of raw materials is conducive to local materials and saves a lot of cost.

(3) After the concrete test block is removed from the formwork, seawater immersion curing is used instead of fresh water curing, which has a simple process, saves material costs and transportation costs, and is environmentally friendly.

(4) Adding triethanolamine rust inhibitor and using fast-hardening sulfoaluminate cement can delay the corrosion of steel bars and improve the service life of artificial fish reefs.

Detailed ways

In order to make the object, technical solution and advantages of the invention clearer, the present invention will be further described in detail through specific examples below.

An artificial fish reef concrete, which is prepared from cement, mixing water, fine aggregate, stones and admixtures, wherein the mass ratio of cement: mixing water: fine bones: stones is 1: (0.3～ 0.5): (1 ~ 1.8): (2.4 ~ 3.4); the preparation method is as follows: first dry mix the mixture of cement, fine aggregate and stones in the mixer, then dissolve the admixture in the mixing water and pour it into Stir in the dry-mixed mixture; pour the artificial reef concrete after mixing; remove the formwork after 12 to 24 hours of artificial reef concrete pouring, and perform seawater curing for 7 to 28 days.

In this embodiment, the artificial fish reef concrete pouring time is preferably 24 hours, and the artificial fish reef concrete pouring seawater curing is preferably 28 days.

In this embodiment, the cement is 42.5 rapid hardening sulfoaluminate cement; the fine aggregate is sea sand; and the mixing water is sea water.

In this embodiment, the admixture includes retarder, water reducer and triethanolamine, the content of the retarder is 0.2-0.4% of the cement content; the content of the water reducer is 1% of the cement content ～2%; the content of the triethanolamine is 1～2% of the cement content.

In this example, ordinary portland cement concrete was introduced as a comparison group. According to the requirements of the compressive strength of artificial reefs, according to JGJ 55-2011 "Ordinary Concrete Mix Proportion Design Regulations" and actual experience, the concrete mix ratio is designed, see Table 1. The meanings of numbers in Table 1 are: B means standard curing, H means seawater curing; S means using rapid hardening sulfoaluminate cement, P means using ordinary Portland cement; 1 means C30 concrete, 2 means C50 concrete. The amount of admixtures (retarder, water reducer, triethanolamine) is the mass percentage of cement.

According to the mixing ratio in Table 1, dry mix cement, fine aggregate and gravel in a mixer for 1 min. Dissolve the admixture in the mixing water first, then pour it into the mixture (cement + fine aggregate + gravel) and stir for 3 min. Afterwards, the slump and slump loss over time were tested according to GB/T50080-2002 "Standards for Test Methods of Performance of Ordinary Concrete Mixtures". The test results are shown in Table 2.

It can be seen from Table 2 that both the slump and slump loss over time of the artificial reef concrete of the HS group meet the construction technology requirements (the slump loss in 2 hours does not exceed 20%), while the BP concrete with the same mix ratio Bleeding and segregation occurred in the group.

The concrete mixture was poured into the test mold, demolded after 24 hours of molding, and the test blocks were subjected to standard curing and seawater curing respectively. According to GB/T50081-2002 "Standard for Test Methods of Mechanical Properties of Ordinary Concrete", the compressive strength and splitting tensile strength of each group at 3d, 7d, and 28d were measured; at the same time, ASTMC 1202 was used to test the artificial reef concrete at 28d. The electric flux was measured, and the test results are shown in Table 3.

It can be seen from the results in Table 3 that the artificial reef concrete whose strength level meets the requirements can be prepared by using the present invention. Compared with common artificial fish reef concrete, the artificial fish reef concrete prepared by the invention has high strength, low chloride ion permeability, high impermeability and good durability.

The improved ASTMC311 concrete effective alkali in-situ dissolution method was used to measure the pH value, and the test blocks of standard curing and seawater curing for 28 days were respectively put into prefabricated molds filled with simulated seawater, so that the test pieces were completely immersed in seawater. Artificial sea water. In order to keep the ion concentration stable, replace it every 24 hours, pour all the soaking liquid into a clean test tube when the detection age is reached, and then use a pH meter to measure the pH value of the leachate in the test tube. Record the change of the pH value of the leach solution of the test piece over time. The obtained artificial reef concrete seepage pH value is shown in Table 4.

It can be seen from Table 4 that for C30 concrete, the pH value of artificial reef concrete maintained in seawater for 28 days was 9.88, which was much lower than 12.23 in the BP group, and the pH value remained constant at 8.3 at 53 days, basically no longer falling, which is different from that of seawater. The pH values were equal, much less than 9.85 in the BP group. For C50 concrete, the pH value of artificial reef concrete maintained in seawater for 28 days is 9.95, which is far less than 12.55 of BP group. At 53 days, the pH value was constant at about 8.33, and basically no longer dropped, which was equal to the pH value of seawater, much lower than 9.86 in the BP group. It shows that the artificial fish reef concrete of the present invention can be reduced to the same pH value as seawater in a short time, thereby benefiting the growth of shellfish, shrimp, fish and algae.

The above descriptions are only preferred embodiments of the present invention, and all equivalent changes and modifications made according to the scope of the patent application of the present invention shall fall within the scope of the present invention.

Claims (10)

1. An artificial fish reef concrete is characterized in that: it is formulated as raw materials with cement, mixing water, fine aggregate, stone and admixture, wherein the mass ratio of cement: mixing water: fine bones: stone is 1:(0.3～0.5):(1～1.8):(2.4～3.4). 2. The artificial fish reef concrete according to claim 1, characterized in that: the cement is 42.5 rapid hardening sulfoaluminate cement, the fine aggregate is sea sand, and the mixing water is sea water. 3. The artificial fish reef concrete according to claim 1, characterized in that: the admixtures include retarder, water reducing agent and triethanolamine. 4. The artificial fish reef concrete according to claim 3, characterized in that: the content of the retarder is 0.2-0.4% of the cement content, the content of the water reducing agent is 1-2% of the cement content, The content of the triethanolamine is 1-2% of the cement content. 5. A method for preparing artificial fish reef concrete, characterized in that: the artificial fish reef concrete is prepared from cement, mixing water, fine aggregate, stones and admixtures, wherein cement: mixing water: fine Orthopedics: The mass ratio of stones is 1:(0.3～0.5):(1～1.8):(2.4～3.4); the artificial fish reef concrete is poured for 12 to 24 hours before the formwork is removed; the artificial fish reef after formwork removal The concrete is cured in seawater for 7-28 days. 6. The preparation method of artificial fish reef concrete according to claim 5, characterized in that: the cement is 42.5 rapid hardening sulfoaluminate cement, the fine aggregate is sea sand, and the mixing water is seawater . 7. The preparation method of artificial fish reef concrete according to claim 5, characterized in that: said admixture comprises retarder, water reducing agent and triethanolamine. 8. The preparation method of artificial fish reef concrete according to claim 7, characterized in that: the mass ratio of the retarder is 0.2% to 0.4% of the cement, and the mass ratio of the water reducer is 0.4% of the cement 1-2%, the mass ratio of the triethanolamine is 1-2% of the cement. 9. The preparation method of artificial fish reef concrete according to claim 5, characterized in that: the pouring time of the artificial fish reef concrete is 24 hours. 10. The preparation method of artificial fish reef concrete according to claim 5, characterized in that: the seawater curing of the artificial fish reef concrete is 28 days.