Method for representing cement hydration degrees by means of low-field nuclear magnetic resonance technology

Abstract

The invention belongs to the field of building materials, and particularly relates to a method for rapidly and continuously representing cement hydration degrees by means of a low-field nuclear magnetic resonance technology. The method comprises the following steps that 1, slurry is prepared, weighing is conducted, the water content m<0> and the cement content m<c> in the cement slurry are calculated, the slurry is rapidly put in a low-field nuclear magnetic resonance instrument, and test is conducted after system parameters and sampling interval time are set; 2, a CPMG impulse sequence is adopted to collect nuclear magnetic resonance transverse relaxation decay signals at t moments in different hydration time; 3, first echo peak amplitudes I(t) of a decay curve at the t moments in the different hydration time are automatically collected, and an amplitude I<0> of a first collection point is recorded; 4, physical combined water amounts m(t) at the hydration t moments are determined through the specific value of the I(t) to the I<0>, and hydration degrees alpha(t) at the hydration t moments are obtained according to the formula in the specification; 5, a relation curve of the alpha(t) and t is drawn, and the hydration degrees at any hydration t moment can be read. According to the method for rapidly and continuously representing the cement hydration degrees by means of the low-field nuclear magnetic resonance technology, drying or stopping of hydration to samples is not needed, and in-situ detection and continuous monitoring to the cement hydration degrees can be achieved.

Description

technical field [0001] The invention belongs to the field of building materials, and in particular relates to a method for characterizing the hydration degree of cement based on low-field nuclear magnetic resonance technology. Background technique [0002] Cement is one of the largest building materials in the civil construction industry. Cement starts to undergo hydration reaction when water is added, gradually solidifies and hardens, and consolidates sand, stones, etc. together to form finished materials such as concrete. In the field of building materials, the characterization of the hydration degree of cement has always been one of the routine experimental projects for scientific research personnel in the industry and for enterprise R&D personnel to develop new products. Therefore, research and development of new technologies and methods for characterizing cement hydration degree have broad application prospects. [0003] According to literature reports [1] , The comm...

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Problems solved by technology

[0003] According to literature reports [1] , The commonly used methods to characterize the degree of cement hydration are: the heat of hydration method, which measures the degree of hydration by measuring the heat released during the cement hydration reaction; The determination of the amount of chemically bound water and calcium hydroxide in the hydration reaction product is used to characterize the degree of hydration. It is necessary to stop the hydration and dry heating of the sample. It is a destructive test method and cannot be used for continuous testing of the same sample.

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