Method for estimating compressive strength of concrete in early stage

A technology of compressive strength and concrete, which is applied in the direction of applying stable tension/compression to test the strength of materials, etc. It can solve the problems of how to know how the strength of concrete develops with age, etc.

Inactive Publication Date: 2014-09-03
王卫仑
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0012] The purpose of the present invention is to provide a method for estimating the compressive strength of concrete at an early stage, aiming at solving the problem that how the strength of concrete on site will develop with age is unknown

Method used

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  • Method for estimating compressive strength of concrete in early stage
  • Method for estimating compressive strength of concrete in early stage
  • Method for estimating compressive strength of concrete in early stage

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0048] Embodiment 1: A certain 1# concrete mix ratio

[0049] Table 1, a 1# concrete mix ratio

[0050] water

cement

fly ash

the sand

stone

Admixture

162

360

40

815

992

6.8

[0051] The mix ratio adopts a certain brand of P.Ⅱ42.5R cement, check the provisions of "General Portland Cement" GB175-2007, as shown in Table 2 below:

[0052] Table 2. Portland cement P.I content of general-purpose Portland cement

[0053]

[0054] It can be seen from Table 2 that the Portland cement accounts for ≥95% of the total mass of the cement. According to the amount of cement and fly ash, the Portland cement accounts for ≥85.5% of the total mass of the cementitious material, and then according to the following table Take the value of C as shown in 3:

[0055] Table 3. C value in weight maturity method

[0056]

[0057]

[0058] As can be seen from Table 3, it is determined that the C value is 1.3 here.

[0059] When...

Embodiment 2

[0078] Embodiment 2: Certain 2# concrete mix ratio

[0079] Table 6, a 2# concrete mix ratio

[0080] water

cement

fly ash

the sand

stone

Admixture

162

360

80

793

970

9.68

[0081] The mix ratio uses a certain brand of P.Ⅱ42.5R cement, check "General Portland Cement" GB175-2007, as shown in Table 2 in Example 1 above, it can be seen that the percentage of Portland cement in the total mass of cement is ≥95% , calculated according to the amount of cement and fly ash, Portland cement accounted for ≥ 77.7% of the total mass percentage of cementitious materials, and then according to the C value reference data, as shown in Table 3 in the above embodiment 1, determine the C value 1.3.

[0082] When placed in the humid heat curing box, the temperature is 20°C, and the results of calculating the weight maturity and strength are shown in Table 7 below:

[0083] Table 7. Test results of a 2# concrete mix ratio weight m...

Embodiment 3

[0089] Embodiment 3: certain 3# concrete mix ratio

[0090] Table 8, a 2# concrete mix ratio

[0091]

[0092]

[0093] The mix ratio uses a certain brand of P.Ⅱ42.5R cement. Check its factory report, it can be seen that the Portland cement accounts for 95% of the total mass of cement. It is calculated according to the amount of cement, fly ash and slag powder. The cement accounts for 61.9% of the total mass of the cementitious material, and then according to the C value reference data (when the C value is greater than 65%, the C value is 1.3, when the C value is 50% to 64%, the C value is 1.4, and when the C value is 35% to 49%, the C value is 1.5, When 35% to 49%, the C value is 1.5), and the C value is determined to be 1.4.

[0094] When placed in the humid heat curing box, the temperature is 20°C, and the results of calculating the weight maturity and strength are as follows:

[0095] Age 24h:

[0096] Among them, 1.5h is from 20°C to 55°C, this part is calculated...

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Abstract

The invention provides a method for estimating the compressive strength of concrete in early stage. The method comprises the following steps of: recording the water filling time, the forming time and the temperature of concrete, carrying out wet and hot curing after a test block is formed, and respectively taking one test block to carry out compressive strength test at the ages of 24 hours and 48 hours; determining the mass percent of Portland cement P.I in cement according to the cement used in the concrete, calculating the mass percent of the Portland cement P.I in the total cementing material according to the proportion of the cement in the total cementing material, and then taking a C value according to the mass percents in C-value reference data; calculating the weight maturity according to different ages and temperatures; establishing a strength prediction relation according to the weight maturity and compressive strength under the wet and hot curing at the temperature of 55 DEG C for 24 hours and 48 hours; and calculating the weight maturity under standard curing at 20 DEG C at the age of 28 days according to the C value, substituting the weight maturity into the strength predication relation to obtain the compressive strength of concrete after standard curing for 28 days. The method provided by the invention has the advantages that the workload is small and the strength predication is more accurate.

Description

technical field [0001] The invention belongs to the fields of construction industry, civil engineering and water conservancy engineering, and in particular relates to a method for estimating the compressive strength of concrete at an early stage. Background technique [0002] Concrete is one of the most important structural materials in construction projects. The 28-day compressive strength of concrete under standard curing is the key quality parameter for evaluating the qualification of concrete sub-projects, and it is also the basis for construction project acceptance. However, due to the long test period of the standard maintenance 28d strength test method, it can neither predict the quality status in construction in time, nor can it design and adjust the concrete mix ratio in time, which is not conducive to strengthening the quality management of concrete and making full use of cement activity. Therefore, it is necessary to study the test method for early estimation of c...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N3/08
Inventor 王卫仑罗启灵邢锋隋莉莉龙武剑
Owner 王卫仑
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