CN117342817A - Road water stabilization base layer biomass retarder, preparation method and application - Google Patents

Abstract

The invention discloses a biomass retarder for road water stabilization base layer, preparation method and application. The biomass retarder includes the following materials: 70% to 90% sodium galactonate solution, 5% to 15% lignosulfonate, and 5% to 15% sodium benzoate. The road water-stabilizing base biomass retarder is prepared through the following steps: whey undergoes a series of biological treatments to obtain a galactose solution, which is oxidized to obtain a galactose acid solution, and a NaOH solution is added during the fermentation process. and obtain a sodium galactonate solution, and then mix the raw materials and stir thoroughly to obtain a biomass retarder. Compared with existing retarder, this biomass retarder is derived from whey, a by-product of the dairy processing industry. It is low-carbon, environmentally friendly, low-priced, safe and harmless, has a simple preparation process, is easy to promote and use, and can significantly extend the cement production time. The condensation time ensures the construction quality of the road's water-stabilized base layer.

Description

A biomass retarder for road water stabilization base layer, preparation method and application

Technical field

The invention relates to the field of road material admixtures, and specifically relates to a biomass retarder for road water stabilization base layer, preparation method and application.

Background technique

The full name of water-stabilized base is cement-stabilized gravel base. It uses cement as the binding material and mixes a certain grade of gravel and water to form a mixture. After compaction and curing, when its strength reaches the specified requirements, This type of base is called cement-stabilized gravel base. Water-stable gravel materials have been widely used in pavement base structures of all levels in my country in recent years due to their advantages of good slab properties, good water stability, and high early strength. According to the requirements of the "Technical Rules for Construction of Highway Pavement Base Course" (JTG/T F20-2015), cement-stabilized materials should be rolled and formed within 2 hours. However, in a large number of actual projects, it often happens that the construction delay time is too long and exceeds the initial setting time of cement. Rolling again at this time will destroy the formed calcium silicate hydrate (C-S-H) and affect the later strength growth of cement. , causing strength loss; at the same time, rolling after forming a certain strength in the early stage will not only consume more mechanical energy, but also affect the degree of compaction. Therefore, the setting time of cement used to stabilize the road's water-stabilized base layer should be comprehensively considered, and appropriate retardant admixtures should be introduced.

In order to extend the construction time of the road's water-stabilized base layer, industry personnel adopt a variety of methods. A common method is to add retarders to extend the setting time of cement. Retarders currently on the market can be divided into two categories: organic and inorganic. They can be subdivided into hydroxycarboxylic acids and their salts, sugary carbohydrates, and lignosulfonates. The retarding effect of sugary carbohydrates such as sucrose is easily affected by pH value, so testing is required before use and the process is cumbersome. Hydroxycarboxylic acids and their salts are often easily affected by temperature. Their retarding effect will be weakened at high temperatures, so the dosage needs to be increased. Lignosulfonate has problems such as poor retarding effect, easy precipitation, and poor stability. At the same time, it has air-entraining properties, which will cause the later strength of concrete to decrease.

Contents of the invention

In order to solve the problems and deficiencies existing in the prior art, the purpose of the present invention is to provide a biomass retarder for road water stabilization base layer, preparation method and application. It solves the problem of short construction time of road water-stabilized base layer, and can effectively improve the problem that existing retarder is greatly affected by environmental conditions such as temperature and pH. At the same time, its production process makes full use of industrial waste whey to achieve It turns a large amount of industrial surplus whey into treasure and is a green and environmentally friendly product.

The technical solution of the present invention is as follows:

A biomass retarder for road water stabilization base layer, including the following components in terms of mass percentage: sodium galactonate solution 70% to 90%, lignosulfonate 5% to 15%, and sodium benzoate 5% to 15% , the sum of the mass percentages of each component is 100%.

Preferably, the mass percentage concentration of the sodium galactonate solution for the biomass retarder for road water stabilization base layer is 10% to 30%.

Preferably, in the road water stabilizing base biomass retarder, the lignosulfonate is one or two or more of sodium lignosulfonate, calcium lignosulfonate, and ammonia lignosulfonate. mixture.

Preferably, the amount of the biomass retarder for the road water-stabilized base layer is 0.2 to 0.6% of the solid mass of the binder in the cement stabilizing material.

The above-mentioned preparation method of biomass retarder for road water stabilization base layer includes the following steps:

(1) Preparation of sodium galactonate solution: 100-300g/L galactose solution is biologically oxidized by Gluconobacter oxidans into galactose acid solution. During the fermentation process, sodium hydroxide solution is used as the neutralizing agent. The galactose solution is low Stop the fermentation at 3g/L, complete the strain, collect the separated liquid and adjust the pH to 6.5 to obtain a sodium galactonate solution.

(2) Mixing of raw materials: Mix sodium galactonate solution, lignosulfonate, and sodium benzoate in proportion, and stir thoroughly until evenly mixed to obtain a road water-stabilizing base biomass retarder.

Preferably, in the preparation method of biomass retarder for road water-stabilizing base layer, the galactose solution in step (1) is derived from whey through hydrolysis, fermentation and separation.

Preferably, in the preparation method of biomass retarder for road water stabilization base layer, the mass percentage concentration of the sodium hydroxide solution in step (1) is greater than 50%.

Beneficial effects of the present invention:

(1) The biomass retarder provided by the present invention can effectively extend the construction time of the road water stabilization base layer, and is especially suitable for use in situations such as poor construction organization and management capabilities and high summer temperatures.

(2) The lignosulfonate used in the present invention can fully disperse the sodium galactonate solution into the water-stabilized base layer, and at the same time, the lignosulfonate can further extend the setting time of cement.

(3) The sodium benzoate used in the present invention can maintain the activity of the sodium galactonate solution for a long time.

Economic benefits:

(1) Compared with traditional sugar-containing carbohydrates, the road water stabilizing base biomass retardant provided by the present invention also functions as a water reducing agent, which can effectively improve the durability of materials and improve the service life of roads, so that the water Stable materials are more economical.

(2) The raw material of the biomass retarder for road water stabilization base provided by the present invention is derived from industrial waste whey. It is low in price, has a simple preparation process, and has good economic benefits.

Environmental benefits:

(1) The road water stabilizing base biomass retarder provided by the present invention is a green and environmentally friendly product. It not only avoids the industrial production of sugary carbohydrates, lignosulfonates and other retarders that consume a large amount of natural resources, but also realizes the industrial "High-value" utilization of solid waste whey.

(2) The whey raw material of the road water stabilizing base biomass retarder provided by the present invention has a huge output, and can be produced through biological methods. The preparation process is simple, the production process has low energy consumption and little pollution, and is in line with sustainable development. The concept helps achieve the "double carbon" construction goal and is easy to promote.

Description of drawings

In order to more clearly explain the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly introduced below.

Figure 1 shows the effect of sodium galactonate biomass retarder dosage on cement setting time;

Figure 2 shows the effect of sodium galactonate biomass retarder dosage on cement initial setting time/and final setting time interval;

Figure 3 is a graph showing the relationship between the settlement depth of the test needle in the cement and its change over time under different dosages of sodium galactonate biomass retarder;

Figure 4 is a comparison chart of the initial setting time of sodium galactonate biomass retarder, sucrose and sodium gluconate as a function of dosage;

Figure 5 is a comparative diagram of the final setting time of sodium galactonate biomass retarder, sucrose and sodium gluconate as a function of dosage.

Detailed ways

The present invention will be further described below with reference to specific examples, but is not limited to the following examples.

In the following specific examples, the cement setting time measurement method is based on the method of GB/T 1346-2011 "Cement Standard Consistency Water Consumption, Setting Time, Stability Test Method".

In the following specific examples, P·O42.5 ordinary Portland cement is used, the test temperature is 20°C, and the mass ratio of water to cement is 140:500 (water-cement ratio 0.28).

The preparation method of a road water stabilizing base biomass retarder provided by the invention is as follows:

(1) Obtain sodium galactonate solution: 100-300g/L galactose solution is biologically oxidized by Gluconobacter oxidans into galactose acid solution. During the fermentation process, sodium hydroxide solution is used as the neutralizing agent. The galactose solution is low Stop the fermentation at 3g/L, complete the strain, collect the separated liquid and adjust the pH to 6.5 to obtain a sodium galactonate solution.

(2) Mixing of raw materials: Mix sodium galactonate solution, lignosulfonate, and sodium benzoate in proportion, and stir thoroughly until evenly mixed to obtain a road water-stabilizing base biomass retarder.

Add the biomass retarder obtained above to the water at a dosage of 0.2%, 0.4%, and 0.6% of the cement mass, mix with the cement, stir evenly, and measure the initial setting time and final setting time.

Example 1

At 20°C, weigh 1g of biomass retarder (0.2%) and 140g of water, add them to the beaker, stir evenly with a glass rod for 1 minute, and set aside for later use.

Example 2

At 20°C, weigh 2g of biomass retarder (0.4%) and 140g of water, add them to the beaker, stir evenly for 1 minute with a glass rod, and set aside for later use.

Example 3

At 20°C, weigh 3g of biomass retarder (0.6%) and 140g of water, add them to the beaker, stir evenly for 1 minute with a glass rod, and set aside.

Example 4

At 20°C, weigh 1g of sucrose (0.2%) and 140g of water, add them to the beaker, stir evenly for 1 minute with a glass rod, and set aside.

Example 5

At 20°C, weigh 2g of sucrose (0.4%) and 140g of water, add them to the beaker, stir evenly for 1 minute with a glass rod, and set aside.

Example 6

At 20°C, weigh 3g of sucrose (0.6%) and 140g of water, add them to the beaker, stir evenly for 1 minute with a glass rod, and set aside.

Example 7

At 20°C, weigh 1g of sodium gluconate (0.2%) and 140g of water, add them to the beaker, stir evenly for 1 minute with a glass rod, and set aside.

Example 8

At 20°C, weigh 2g sodium gluconate (0.4%) and 140g water, add them to the beaker, stir evenly for 1 minute with a glass rod, and set aside.

Example 9

At 20°C, weigh 3g sodium gluconate (0.6%) and 140g water, add them to the beaker, stir evenly for 1 minute with a glass rod, and set aside.

Baseline group

At 20°C, weigh 140g of water, add it to the beaker, and set it aside for later use.

The retarder prepared in the above-mentioned Examples 1 to 9 was mixed with the reference group and the cement according to the amount for performance testing. The setting time was mainly tested, and the setting time test standard was in accordance with GB/T 1346-2011 "Cement Standard Consistency Water Test the quantity, setting time and stability test method.

The initial setting time and final setting time of the above-mentioned Examples 1 to 9 and the reference group were measured, and the data were recorded in Table 1.

Table 1 Comparison table of cement setting time between different dosages of retarder and the benchmark group

Note: The mass fraction of sucrose and sodium gluconate is 10%.

According to the experimental data in Table 1, compared with the benchmark group, the biomass retarder prepared by the present invention can effectively prolong the setting time of cement and ensure the construction quality of the water-stabilized base layer to a certain extent.

It can be seen from Figure 1 that the initial setting time of the benchmark group is 249min, and the initial setting time of Example 1, Example 2, and Example 3 are 341min, 405min, and 471min respectively, which are 37%, 63%, and 37% higher than the benchmark group respectively. 89%. Compared with the baseline group, as the addition amount increases, the final setting time of cement paste increases by 35%, 60% and 90% respectively.

It can be seen from Figure 2 that as the addition amount increases, the interval time between the initial setting state and the final setting state of the cement paste continues to increase.

As can be seen from Figure 3, the figure shows the relationship curve between the settlement depth of the test needle in the cement slurry and time. It can be seen that as time goes by, the settlement depth of the test needle in the cement slurry gradually decreases. Furthermore, the baseline group first showed a downward inflection point, indicating that it reached the initial setting state at the earliest. As the addition amount increases, the time for the cement paste to reach the initial setting state becomes later and later, and the final setting state also shows the same trend.

It can be seen from Figures 4 and 5 that biomass retarder, sucrose and sodium gluconate can prolong the setting time of cement. The initial setting time and final setting time of biomass retarder and sodium gluconate are not much different, indicating that the retarding effect of the two is equivalent; the setting time of both is longer than that of sucrose, indicating that its retarding effect is better than that of sucrose.

The above results show that biomass retarder can effectively prolong the setting time of cement. In particular, the more retarder is added, the longer it takes for the cement to reach the initial setting and final setting states, and the corresponding interval time is also longer. When used in actual engineering construction, it can maintain a certain plasticity of fresh concrete for a long time, which facilitates subsequent construction and pouring. At the same time, it can delay the occurrence of the peak temperature of the concrete, reduce the peak temperature, and reduce the growth of cracks, which is related to Provide important guarantee for project quality.

The above are only preferred embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art, several improvements can be made without departing from the principles of the present invention, and these improvements should also be regarded as the present invention. protection scope of the invention.

Claims (7)

1. The biomass retarder for the road water-stable base layer is characterized by comprising the following components in percentage by mass: 70-90% of sodium galactonate solution, 5-15% of lignosulfonate, 5-15% of sodium benzoate and 100% of the sum of the mass percentages of the components.

2. The road water stabilization base biomass retarder of claim 1, wherein the concentration of the sodium galactonate solution is 10-30% by mass.

3. The road water-stable base layer biomass retarder of claim 1, wherein the lignosulfonate is one or a mixture of two or more of sodium lignosulfonate, calcium lignosulfonate and ammonium lignosulfonate.

4. The biomass retarder for the road water-stable base layer according to claim 1, wherein the dosage of the biomass retarder for the road water-stable base layer is 0.2-0.6% of the solid mass of a binder in a cement-stable material.

5. The method for preparing the biomass retarder for the road water-stable base layer, which is characterized by comprising the following steps:

(1) Preparation of sodium galactonate solution: and (3) biologically oxidizing 100-300 g/L galactose solution into galactose acid solution by using gluconobacter oxydans, wherein a sodium hydroxide solution is adopted as a neutralizing agent in the fermentation process, the galactose solution is lower than 3g/L to stop fermentation, the strain is completed, and the pH of the separating liquid is collected and adjusted to 6.5 to obtain the sodium galactose solution.

(2) Mixing raw materials: mixing the sodium galactonate solution, the lignosulfonate and the sodium benzoate in proportion, and fully stirring until the mixture is uniform, thus obtaining the road water stable base biomass retarder.

6. The method for preparing the biomass retarder for the road water-stable base layer according to claim 5, wherein the galactose solution rice in the step (1) is obtained by hydrolyzing, fermenting and separating whey.

7. The method for preparing the biomass retarder for the road water-stable base layer according to claim 5, wherein the mass percentage concentration of the sodium hydroxide solution in the step (1) is more than 50%.