SU781187A1 - Method of preparing polymer-concrete mixture - Google Patents

Description

one

The invention relates to a technology for producing polymer concrete mixtures and can be used for the manufacture of building products, as well as in the repair of building structures.

A known method of preparing a polymer concrete mixture by mixing the binder with coarse and pre-activated dispersed mineral filler l. YU

The closest to the proposed technical essence and the achieved result is a method for preparing a polymer concrete mixture by pretreatment of fine-grained filler with low-molecular-weight polyethylene, followed by mixing it with coarse aggregate, binder, and mixing water 2.20

The disadvantage of this method is insufficient cement strength, high shrinkage and high water absorption.

The purpose of the invention is to increase cement strength, reduce shrinkage and water absorption.

The goal is achieved by the fact that, in the method of preparing a polymer, a concrete mix by preliminary 30

processing fine-grained filler with low-molecular polyethylene, followed by mixing it with coarse aggregate, binder and mixing water, fine-grained filler is treated with molten 1% low molecular weight polyethylene in the amount of 0.18-1.8% by weight of emitting water, and polyvinyl acetate dispersion.

The activation of the dispersed mineral filler by low molecular weight polyethylene ensures uniform mixing of the filler with the binder and additives with the formation of a structure impervious to aggressive media with a slight shrinkage.

In order to prepare the polymer concrete mixture according to the proposed weighed amount of dispersed mineral filler, it is loaded into a conventional type concrete mixer and, with continuous mixing, pre-molded low molecular weight polyethylene with a molecular weight of 10005000, taken in an amount of 0.18-1.8% by weight of portland cement, is introduced. After 2-3 minutes, water is added to the stirred mixture in an amount of 50% of

, its total amount with the polyvinyl acetate dispersion dissolved in it, coarse aggregate and portland cement. After that, the rest of the water is added.

Examples of polymer mixtures obtained according to the invention are given

in tab. one.

From the prepared concrete mixes, prism samples are made of a size of 10 "10i 40 cm and cubic samples of cm size. Samples are tested for shrinkage and compressive strength. Beacon loss is determined 28 days after immersion of concrete samples with reinforcement in a 5% KCf solution according to the formula

m-i - WT.

(g / m).

R

weight loss, g / m;

where P t is the initial mass of reinforcement, g;

mass of reinforcement after testing 2 tany, g, 2 sample surface, m. S In the table. 2 shows the physical and mechanical parameters of the samples.

As can be seen from the table. 2 samples from polymer concrete mixtures obtained by the proposed method have an average strength of 40%, shrinkage is 1.5-2 times lower and water absorption is lower by more than 3 times compared to samples from polymer concrete mixture obtained in a known manner. In addition, after testing in an aggressive environment, a decrease in the strength of samples from mixtures obtained by the proposed method is 12%, and according to the known method - 30%.

The proposed method provides for the production of polymer mixture, the products from which have high physicomechanical protective properties, which increases the service life of building structures by 1.5-2 times.

To obtain data confirming the possibility of uniform mixing of the molten low molecular weight polyethylene with a filler, the filler (sand) is processed by mixing with the molten low molecular weight polyethylene and milled. Thus, b batches of sand are processed, processed by the known and proposed method with minimum, average and maximum content (see Table 1) of low molecular weight polyethylene and sand.

From each batch of treated sand, 10 samples are taken from different places. A portion of each sample is placed in a porcelain crucible and calcined at b00 ° C.

The percentage of low molecular weight polyethylene in each sample is calculated by the formula

at 11. 100%,

where B is the content of low molecular weight polyethylene in the sample, m, j is the weight of the sample before calcination, t 2 weight of the sample after calcination.

The test results are presented in table. 3

Table 3 shows the results of testing sand samples. . From tab. 3, it can be seen that the results obtained by the proposed method differ in a smaller scatter of data and. a smaller deviation of the mean values from the amount of the low molecular weight polyethylene introduced, which indicates a high uniformity of the distribution of the low molecular weight polyethylene (n.m PE).

Thus, the proposed method allows to obtain polymer mixtures, products from which have high physicomechanical and protective properties.

Table 1

Table 2 ,

320 360 383 420 350 240 260 305 0.6 0.3 0.3 0.3

T a

faces

Claims (2)

1. USSR author's certificate 399479, cl. From 04 to 25/00. 2. USSR author's certificate number 442166, cl. From 04 To 13/20, 1975.