CS199772B1 - Plasticiser and rate of solidification of cement mixture and mortars modifier - Google Patents

Description

The present invention relates to the plasticization and modification of the solidification rates of cementitious mixtures and mortars using a mixture of sulfo and sulfito esters of 1,3 dimethylol-4,5-dihydroxyimidazoline for this purpose.

It is known to treat con. urea, formaldehyde densate and glyoxal form a mixture of 1,3-dimethylol-4,5-dihydroxyimidazoline monosulfoester, 1,3-dimethylol-4,5-dihydroxyimidazolidone monosulfoester, 1,3-dimethyl-4,5-dihydroxyimidazolidone monosulfoester and disulfitoester 1, 3-dimethylol-4,5-dihydroxyimidazolidone. To date, mixtures of these substances have been used to a lesser extent in the paper industry as hardeners to improve the paper's performance.

It has now been feared that a mixture of 1,3-dimethylol-4,5-dihydroxyimidazolidone monosulfoester, 1,3-dimethylol-4,5-dihydroxyimidazolidone disulfoester, 1,3-dimethyl-4,5-dihydroxyimidazolidone monosulfitoester, and 1,3-dimethylol disulfitoester 4,5 - dihydroxyimidazolidone has a high plasticizing effect and at the same time decisively affects the setting time of the cementitious compound. This unexpected and surprising property makes this mixture particularly suitable as an additive in concrete and mortar. The plasticizing effect found in the composition according to the invention is manifested by the fact that it is possible to prepare mixtures of concrete or mortar of considerable flowability without increasing the mixing water content, thereby permitting the processing of water.

199 772 of low water content mixtures giving concrete of higher strength. Another newly discovered property of the composition is that it greatly affects the setting and curing time of the cementitious composition. This newly discovered property of the aforementioned mixture can be used very successfully to speed up concrete works in the building industry. The influence on the setting and hardening time of concrete mixtures discovered in the mixture of the abovementioned substances is manifested differently on different concrete mixtures and mortars in such a way that the hardening of some concrete mixtures accelerates and slows down others. It has been found that the mineralogical composition of the cement used in the concrete mix plays an important role here. In the case of slag-Portland cement, the addition of the above mixture slows and hardens, while Portland cements significantly accelerate solidification. The practical significance of the use of the above mentioned newly-discovered properties of * ¹ above mixture is large. On the one hand there is a significant acceleration of concrete work, not only in the building industry, but also in the production of prefabricated concrete parts, but on the other hand, it is possible to significantly extend the pot life of mixtures when transported by truck mixers or other transport means. longer distances from the central mixing cores.

The composition of the mixture used varies according to the conditions under which the sulfation and sulfitation were carried out in the range determined by the ratio of the resulting monoester to the diester, which is 1: 0.2 to 0.8.

The invention finds use in the building and prefabricated construction industry.

Example 1

It is fed into the central mixer with automatic scales

Cement PC 400 300 kg Aggregate fraction up to 8 mm 1,030 kg Aggregate fraction 8 to 16 mm 872 kg Water 165.5 kg Additive 0.6 kg

After 5 minutes homogenization, the mixture is processed in a heavily reinforced prefabricated part. After 1.5 min. compaction is the mixture left to cure.

Example 2

It is fed into the central mixer with automatic scales

Cement SPC 325 300 kg Aggregate fraction up to 8 mm 1,030 kg Aggregate fraction 8 to 16 mm 872 kg Water 165 kg Additive 0.6 kg

199 772

After homogenization for five minutes, the mixture is processed into a concrete product. After 1.5 min. compacting the mixture is left to set and harden.

In the embodiment according to example a 2, the following properties of

new mixtures Species used cement Quantity of blend used (% by weight) Concrete slurry consistency (VeBe) Start of setting (min.) End solidification (min) Concrete strength (28 days) (MPa) PC 400 - 40 158 233 29.9 PC 400 0.2 30 61 131 23.7 PC 325 - 38 205 293 21.1 PC 325 0.2 32 275 360 22.6 The PC 400 has a distinctive content Alite, quantity is ranging from 60% to 60% 70 S6. Medium content

- content between 20% and 25%. The content of hydrated CaOHg released is 2% to 3%. CjA is present in a significant amount, namely 12% to 18%, and calcite is present in a smaller amount.

The PC 325 cement contains less alite and a higher proportion of belite compared to PC 400. Calcite is contained in a small amount. The formation of portlandite cannot be recorded.

SEVENTE OF THE INVENTION

Claims (1)

THE SEVENTE OF THE INVENTION Use of a mixture of 1,3-dimethylol-4,5-dihydroxyimidazolidone monosulfoester, 1,3-dimethylol-4,5-dihydroxyimidazolidone disulfoester, 1,3-dimethyl-4,5-dihydroxyimidazolidone monosulfitoester and 1,3-dimethylol-4,5 disulfitoester dihydroxyimidazolidone and 1,3 - dimethylol - 4,5 - dihydroxyimidazolidone disulfitoester as plasticizer and solidification modifier for cementitious mixtures and mortars.