Method for measuring and calculating water absorption rate of coral aggregate in whole coral cement concrete

Abstract

The invention discloses a method for measuring and calculating the water absorption rate of coral aggregate in whole coral cement concrete. The method comprises the following steps: step 1, designing a reference group mix proportion; step 2, designing a mix proportion of a comparison group; step 3, preparing coarse and fine coral aggregates; step 4, mixing a reference group mixture; step 5, obtaining the actual water adding amount of the mixture of the reference group; step 6, mixing a contrast group mixture; 7, obtaining the actual water adding amount of the mixture of the comparison group; step 8, judging a slump average value; 9, calculating the actual water absorption rate of the coral aggregate; and step 10, adjusting the slump of the mixture of the comparison group. The method is simple, scientific and practical, is consistent with practical application, and compared with an existing method, obtained data are more scientific and accurate and easier to understand, apply and popularize.

Description

Technical Field

[0001] The invention relates to the technical field of coral aggregate water absorption rate calculation, and in particular to a method for calculating the water absorption rate of coral aggregate in full-coral cement concrete. Background Art

[0002] The mix design and construction application promotion of all-coral concrete require accurate coral aggregate water absorption rate. The water-cement ratio calculation is the first step in the mix design. The coral aggregate water absorption rate seriously affects the actual water-cement ratio of all-coral concrete and the success of all-coral concrete mix design. The actual water consumption is the sum of the net water consumption and the additional water consumption. The additional water consumption is the actual water absorption of the coarse and fine aggregates of the coral. Obtaining the water absorption rate of the coarse and fine aggregates of the coral is an extremely important step.

[0003] At present, there is no standard for the mix design of all-coral cement concrete similar to the "Ordinary Cement Concrete Mix Design Code" in the world. The references mentioned that the coral coarse and fine aggregates should be pre-wetted before mixing, so that the aggregates will no longer absorb and overflow water during the mixing process, so that the mixing water consumption is the net water consumption of all-coral concrete, but the literature does not specifically state the state and standard of pre-wetting. The water content of coral fine aggregate in the surface dry state can be tested by the slump cone method, that is, the water absorption rate of coral fine aggregate. It is not appropriate to use the water content of coral coarse aggregate in the surface dry state to determine the water absorption rate when mixing and molding.

[0004] In the existing measurement technology, because coral sand has fine particles, its open and closed pores are much less than coral coarse aggregate. Although its water absorption rate is much higher than river sand, its various properties are close to river sand. The measured water absorption rate of all-coral concrete is basically consistent with the water absorption rate tested by JTG E42-2005 "Highway Engineering Aggregate Test Code" T 0330-2005. Coral coarse aggregate has a large number of open voids and closed pores. The water absorption rate tested by JTG E42-2005 "Highway Engineering Aggregate Test Code" T 0304-2005 is as high as about 15%, which is very different from the test results in the actual test mix. Therefore, the test method in the code is not suitable for coral coarse aggregate.

[0005] The reason for the huge difference in the test results is that when the coral aggregate is in a dry state (the aggregate water absorption rate regulations require testing in this state), its free water will flow out under the action of centrifugal force during the mixing process and gravity during vibration molding (we need the water absorption rate when the aggregate no longer flows out water at this time), which will seriously affect the mixing quality and strength of the concrete. Therefore, scientific calculation of the coral aggregate water absorption rate is necessary to improve the full coral concrete mix design standard. Summary of the invention

[0006] The invention aims to provide a method for calculating the water absorption rate of coral aggregate in all-coral cement concrete, which solves the problem of obtaining the water absorption rate of coral aggregate.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] The method for calculating the water absorption rate of coral aggregate in all-coral cement concrete includes the following steps:

[0009] Step 1: Benchmark mix design: According to the design drawings, construction technical specifications and specific conditions of on-site construction, complete the required all-coral cement concrete benchmark mix design;

[0010] Step 2: Design of the comparison group mix ratio: Based on the capacity of the laboratory mixer at the construction site and the benchmark mix ratio, calculate a comparison group mix ratio with the same capacity, water-binder ratio and cement dosage as the benchmark group, but with the sand ratio increased or decreased by 3%, and calculate the dosage of various materials;

[0011] Step 3: Preparation of coarse and fine coral aggregates: Dry the coarse and fine coral aggregates for later use;

[0012] Step 4: Mixing of the reference group mixture: Weigh various materials according to the reference mix ratio and add them into the mixer for mixing. After mixing, release them and complete the pot washing and formal trial mixing;

[0013] Step 5. Obtaining the actual amount of water added to the benchmark group mixture: Observe the state of the benchmark group mixture, increase the amount of water until the expected slump is reached, record the actual amount of water added, test the slump twice immediately after it comes out of the pot, and record the average value;

[0014] Step 6: Mixing of the comparative group mixture: Weigh various materials according to the comparative group mix ratio and add them into the mixer for mixing. After mixing, release them and complete the pot washing and formal trial mixing;

[0015] Step 7. Obtaining the actual amount of water added to the comparison group mixture: Observe the state of the comparison group mixture, increase the amount of water until it reaches the same final state as the reference group mixture, record the actual amount of water added, and immediately test the slump twice after it comes out of the pot, and record the average value;

[0016] Step 8: Determine the average slump value: Calculate the difference between the average slump value of the comparison group mixture and the average slump value of the reference group mixture. If the difference is not within the design range, proceed to step 9; if the difference is within the design range, proceed to step 10;

[0017] Step 9, slump adjustment of the comparison group mixture: when the difference between the average slump of the comparison group mixture and the average slump of the reference group mixture exceeds the design range, remix the comparison group mixture, adjust the actual amount of water added until the difference between the slump of the reference group mixture and the slump of the reference group mixture is within the design range, and then proceed to step 10;

[0018] Step 10. Calculation of actual water absorption of coral aggregate: When the difference between the average slump of the comparison group mixture and the average slump of the benchmark group mixture is within the design range, substitute it into the two-variable linear equation system to solve the actual water absorption of coral fine aggregate and the actual water absorption of coral coarse aggregate.

[0019] Preferably, in step five and step seven, the accuracy of the actual amount of water added is 1 mm.

[0020] Preferably, in step seven, the final state is consistent in that the difference between the slump of the comparison group mixture and the slump of the reference group mixture is controlled within 3 mm.

[0021] Preferably, in step eight, the design range is specifically ±3 mm.

[0022] Preferably, in step 10, when the comparison group mix ratio is obtained by increasing the sand rate by 3%, the binary linear equation system is:

[0023]

[0024] Where:

[0025] m 净 The net unit water consumption of all coral concrete under this mix ratio after deducting the water absorption rate of coral coarse and fine aggregates (kg / m 3 ); m is the total unit consumption of coral coarse and fine aggregates assuming the same capacity, the same cement consumption (kg / m 3 );

[0026] m1 is the actual amount of water added to the base mix (kg / m 3 );

[0027] m2 is the actual amount of water added to the comparison group mixture (kg / m 3 );

[0028] β s is the sand ratio (%);

[0029] x is the measured water absorption rate of coral fine aggregate;

[0030] y is the measured water absorption rate of coral coarse aggregate.

[0031] Preferably, in step 10, when the comparison group mix ratio is obtained by reducing the sand ratio by 3%, the binary linear equation system is:

[0032]

[0033] Where:

[0034] m 净The net unit water consumption of all coral concrete under this mix ratio after deducting the water absorption rate of coral coarse and fine aggregates (kg / m 3 ); m is the total unit consumption of coral coarse and fine aggregates assuming the same capacity, the same cement consumption (kg / m 3 );

[0035] m1 is the actual amount of water added to the base mix (kg / m 3 );

[0036] m2 is the actual amount of water added to the comparison group mixture (kg / m 3 );

[0037] β s is the sand ratio (%);

[0038] a is the measured water absorption rate of coral fine aggregate;

[0039] b is the measured water absorption rate of coral coarse aggregate.

[0040] The present invention adds appropriate amount of water to the reference group mixture and the comparison group mixture, so that the two groups of mixtures reach a slump that is basically consistent with the construction or design requirements, and the slump of the two groups is controlled to be maintained within 3 mm. The material dosage parameters of the reference group mixture and the comparison group mixture at this time are substituted into a binary linear equation system to solve the actual water absorption rate of the coral fine aggregate and the actual water absorption rate of the coral coarse aggregate.

[0041] The all-coral cement concrete trial mixing simulation project is applied to practice. Based on the water reduction rate detection method of cement concrete water reducer, a set of two-variable linear equations with coral coarse aggregate and coral fine aggregate as unknowns is established to calculate the actual water absorption rate of coral coarse aggregate and fine aggregate used in scientific, reasonable and practical all-coral cement concrete, which serves to successfully complete the all-coral cement concrete mix design and construction application promotion.

[0042] Although the existing testing methods have unified standards, they are not consistent with actual construction production. This method is simple, scientific, practical, consistent with actual applications, more practical than existing methods, and the data obtained are more scientific and accurate, and easier to understand and apply. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a flow chart of the present invention when the sand rate increases by 3%. DETAILED DESCRIPTION

[0044] The present invention will be further described with reference to the following drawings:

[0045] like Figure 1 As shown, the method for calculating the water absorption rate of coral aggregate in all-coral cement concrete includes the following steps:

[0046] Step 1: Benchmark mix design: According to the design drawings, construction technical specifications and specific conditions of on-site construction, complete the required all-coral cement concrete benchmark mix design;

[0047] Step 2: Design of the comparison group mix ratio: Based on the capacity of the laboratory mixer at the construction site and the benchmark mix ratio, calculate a comparison group mix ratio with the same capacity, water-binder ratio and cement dosage as the benchmark group, but with the sand ratio increased or decreased by 3%, and calculate the dosage of various materials;

[0048] Step 3: Preparation of coarse and fine coral aggregates: Dry the coarse and fine coral aggregates for later use;

[0049] Step 4: Mixing of the reference group mixture: Weigh various materials according to the reference mix ratio and add them into the mixer for mixing. After mixing, release them and complete the pot washing and formal trial mixing;

[0050] Step 5. Obtain the actual amount of water added to the benchmark group mixture: Observe the state of the benchmark group mixture, increase the amount of water until the expected slump is reached, record the actual amount of water added, test the slump twice immediately after it comes out of the pot, and record the average value. The accuracy of the actual amount of water added is 1mm;

[0051] Step 6: Mixing of the comparative group mixture: Weigh various materials according to the comparative group mix ratio and add them into the mixer for mixing. After mixing, release them and complete the pot washing and formal trial mixing;

[0052] Step 7. Obtaining the actual amount of water added to the comparison group mixture: Observe the state of the comparison group mixture, increase the amount of water until it reaches the same final state as the reference group mixture, that is, the difference between the slump of the comparison group mixture and the slump of the reference group mixture is controlled within 3mm, record the actual amount of water added, and immediately test the slump twice after taking it out of the pot, and record the average value. The accuracy of the actual amount of water added is 1mm;

[0053] Step 8. Determination of the average slump value: Calculate the difference between the average slump value of the comparison group mixture and the average slump value of the reference group mixture. If the difference is not within the design range of ±3 mm, proceed to step 9; if the difference is within the design range of ±3 mm, proceed to step 10;

[0054] Step 9, slump adjustment of the comparison group mixture: when the difference between the average slump of the comparison group mixture and the average slump of the reference group mixture exceeds the design range, remix the comparison group mixture, adjust the actual amount of water added until the difference between the slump of the reference group mixture and the slump of the reference group mixture is within the design range, and then proceed to step 10;

[0055] Step 10. Calculation of actual water absorption of coral aggregate: When the difference between the average slump of the comparison group mixture and the average slump of the reference group mixture is within the design range of ±3 mm, substitute it into the two-variable linear equation system to solve the actual water absorption of coral fine aggregate and the actual water absorption of coral coarse aggregate;

[0056] When the comparison group mix ratio is obtained by increasing the sand rate by 3%, the binary linear equation system is:

[0057]

[0058] Where:

[0059] m 净 The net unit water consumption of all coral concrete under this mix ratio after deducting the water absorption rate of coral coarse and fine aggregates (kg / m 3 ); m is the total unit consumption of coral coarse and fine aggregates assuming the same capacity, the same cement consumption (kg / m 3 );

[0060] m1 is the actual amount of water added to the base mix (kg / m 3 );

[0061] m2 is the actual amount of water added to the comparison group mixture (kg / m 3 );

[0062] β s is the sand ratio (%);

[0063] x is the measured water absorption rate of coral fine aggregate;

[0064] y is the measured water absorption rate of coral coarse aggregate;

[0065] When the comparison group mix ratio is obtained by reducing the sand ratio by 3%, the binary linear equation system is:

[0066]

[0067] Where:

[0068] m 净 The net unit water consumption of all coral concrete under this mix ratio after deducting the water absorption rate of coral coarse and fine aggregates (kg / m 3 ); m is the total unit consumption of coral coarse and fine aggregates assuming the same capacity, the same cement consumption (kg / m 3 );

[0069] m1 is the actual amount of water added to the base mix (kg / m 3 );

[0070] m2 is the actual amount of water added to the comparison group mixture (kg / m 3 );

[0071] β s is the sand ratio (%);

[0072] a is the measured water absorption rate of coral fine aggregate;

[0073] b is the measured water absorption rate of coral coarse aggregate.

[0074] In one embodiment: It is known that C25 all-coral concrete is composed of PO 42.5 cement, 4.75-16mm coral crushed material, 0-2.36mm coral sand and drinking water, with a water-cement ratio of 0.60, a sand rate of 51%, and a designed slump of 70-90mm.

[0075] Benchmark mix ratio

[0076] Cement: coarse aggregate: fine aggregate: water = 367:833:800:220 (kg / m 3 ), actual water addition amount 306.2 (kg / m 3 ), after mixing, the average slump of the benchmark group mixture was 78 mm.

[0077] The sand ratio is increased by 3% based on the benchmark mix ratio to form the comparison mix ratio.

[0078] Cement: coarse aggregate: fine aggregate: water = 367:882:751:220 (kg / m 3 ), the slump of the mixture reached 78 mm, and the actual amount of water added was 307.8 (kg / m 3 ), the measured water absorption rate of fine aggregate coral sand is 6.8%.

[0079]

[0080] Substituting the water absorption rate of fine aggregate a=6.8% into the equation, we can solve the water absorption rate of coarse aggregate b=3.7%, which means the actual water absorption rate of coral coarse aggregate is 3.7%. Based on this, we can prepare and process various all-coral concretes with this type of coral coarse and fine aggregates.

[0081] The specific material composition of coral sand and coral crushed coarse aggregate varies from region to region, and their water absorption rate must be based on the results of on-site sampling and indoor testing.

[0082] The above embodiments are only some illustrations of the concept and implementation of the present invention, and are not intended to limit the same. Under the concept of the present invention, technical solutions that have not been substantially changed are still within the scope of protection.

Claims

1. A method for calculating the water absorption rate of coral aggregate in all-coral cement concrete, characterized in that: The following steps are involved: Step 1: Benchmark mix design: Complete the benchmark mix design of all-coral cement concrete according to the design drawings, construction technical specifications and specific conditions of on-site construction; Step 2: Design of the comparison group mix ratio: Based on the capacity of the laboratory mixer at the construction site and the benchmark mix ratio, calculate a comparison group mix ratio with the same capacity, water-binder ratio and cement dosage as the benchmark group, but with the sand ratio increased or decreased by 3%, and calculate the dosage of various materials; Step 3: Preparation of coarse and fine coral aggregates: Dry the coarse and fine coral aggregates for later use; Step 4: Mixing of the reference group mixture: Weigh various materials according to the reference mix ratio and add them into the mixer for mixing. After mixing, release them and complete the pot washing and formal trial mixing; Step 5. Obtaining the actual amount of water added to the benchmark group mixture: Observe the state of the benchmark group mixture, increase the amount of water until the expected slump is reached, record the actual amount of water added, test the slump twice immediately after it comes out of the pot, and record the average value; Step 6: Mixing of the comparative group mixture: Weigh various materials according to the comparative group mix ratio and add them into the mixer for mixing. After mixing, release them and complete the pot washing and formal trial mixing; Step 7. Obtaining the actual amount of water added to the comparison group mixture: Observe the state of the comparison group mixture, increase the amount of water until it reaches the same final state as the reference group mixture, record the actual amount of water added, and immediately test the slump twice after it comes out of the pot, and record the average value; Step 8: Determine the average slump value: Calculate the difference between the average slump value of the comparison group mixture and the average slump value of the reference group mixture. If the difference is not within the design range, proceed to step 9; if the difference is within the design range, proceed to step 10; Step 9, slump adjustment of the comparison group mixture: when the difference between the average slump of the comparison group mixture and the average slump of the reference group mixture exceeds the design range, remix the comparison group mixture, adjust the actual amount of water added until the difference between the slump of the reference group mixture and the slump of the reference group mixture is within the design range, and then proceed to step 10; Step 10. Calculation of actual water absorption of coral aggregate: When the difference between the average slump of the comparison group mixture and the average slump of the benchmark group mixture is within the design range, substitute it into the two-variable linear equation system to solve the actual water absorption of coral fine aggregate and the actual water absorption of coral coarse aggregate.

2. The method for calculating the water absorption rate of coral aggregate in all-coral cement concrete according to claim 1, characterized in that: In step five and step seven, the accuracy of the actual amount of water added is 1 mm.

3. The method for calculating the water absorption rate of coral aggregate in all-coral cement concrete according to claim 1 or 2, characterized in that: In step seven, the final state is consistent in that the difference between the slump of the comparison group mixture and the slump of the reference group mixture is controlled within 3 mm.

4. The method for calculating the water absorption rate of coral aggregate in all-coral cement concrete according to claim 3, characterized in that: In step eight, the design range is specifically ±3 mm.

5. The method for calculating the water absorption rate of coral aggregate in all-coral cement concrete according to claim 4, characterized in that: In step 10, when the comparison group mix ratio is obtained by increasing the sand rate by 3%, the binary linear equation system is: Where: m 净 The net unit water consumption of all coral concrete under this mix ratio after deducting the water absorption rate of coral coarse and fine aggregates (kg / m 3 ); m is the total unit consumption of coral coarse and fine aggregates assuming the same capacity, the same cement consumption (kg / m 3 ); m1 is the actual amount of water added to the base mix (kg / m 3 ); m2 is the actual amount of water added to the comparison group mixture (kg / m 3 ); β s is the sand ratio (%); a is the measured water absorption rate of coral fine aggregate; b is the measured water absorption rate of coral coarse aggregate.

6. The method for calculating the water absorption rate of coral aggregate in all-coral cement concrete according to claim 4 or 5, characterized in that: In step 10, when the comparison group mix ratio is obtained by reducing the sand ratio by 3%, the binary linear equation system is: Where: m 净 The net unit water consumption of all coral concrete under this mix ratio after deducting the water absorption rate of coral coarse and fine aggregates (kg / m 3 ); m is the total unit consumption of coral coarse and fine aggregates assuming the same capacity, the same cement consumption (kg / m 3 ); m1 is the actual amount of water added to the base mix (kg / m 3 ); m2 is the actual amount of water added to the comparison group mixture (kg / m 3 ); β s is the sand ratio (%); a is the measured water absorption rate of coral fine aggregate; b is the measured water absorption rate of coral coarse aggregate.

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