CS254243B1 - Portland or slagportland cement with increased tumbling strength - Google Patents

Abstract

The solution concerns Portland or slag Portland cement with increased initial strengths. The essence of the solution is Portland or slag Portland cement made from clinker with a tricalcium silicate content of over 56 wt. %/o, with a specific surface area of 250 to 1,000 m2. kg-i Blaine stage, characterized in that it contains a reaction product of an aqueous solution of triethanolamine and hydrochloric acid with a pH value of 7.5 to 9.0. Cement with increased strengths according to the solution can be used in prefabrication, for assembly grouting, construction of cores and reservoirs with sliding formwork, in adverse weather conditions, in concrete technologies with cast concrete, or for reconstruction work during operation.

Description

The invention relates to Portland or slag-portland cement with increased initial strengths.

Construction practice of cements with increased initial strengths for the production of concretes with increased initial strengths, for the production of concretes at normal temperatures, for accelerating the hardening of concretes by · overheating and winter concreting.

For all these purposes, cement with calcium chloride is suitable. However, the calcium chloride additive cannot be used in reinforced concrete because it causes corrosion of the steel reinforcement, {SEBOK, T .: Additives and Additives for Mortars and Concrete, Prague SNTL 1985, p. 9).

Cement mixtures containing an additive of aluminum sulphate are known from the literature (BECHYNĚ, L .: Technologie betonu, SNTL Praha 1954, p. 581). In the fresh state, however, cementitious compounds with aluminum sulphate additive have a false solidification, (JOISEL, A .: Admixtures for cement, published by Soisu, France 1973, p. 127), making it virtually impossible to use them to accelerate hardening and increase strength.

Other ways of obtaining cements with increased initial strengths are mainly the altered mineralogical composition of clinker as compared to ordinary Portland clinker. They are based on the acquisition of active belite clinkers, sulfoaluminiumbelite, halogen-containing clinkers, etc., (HOROSČÁK, T. and KOL .: Research of new types of silicate-based cements with programmable properties, VÚSH Brno 1982). Production of said clinkers, respectively. cement requires new expensive raw materials, their transport and also the modification of technological equipment, respectively. production, and often the environment, which is a disadvantage.

Many interesting results have resulted from suitable additives having a similar effect to calcium chloride. sodium thiosulfate increases the hydration rate of tricalcium silicate, although not as effective as calcium chloride (ZIELINSKA, E .: Chem. abstr., 92, 115 370, (1980)) , (TAVLINOVA, I., DOVYBOROVA, LN: Chem. Abstr., 92, 46 339, (1980). The disadvantage of the above mentioned additives or designs of cements with increased initial strengths is low efficiency, difficult handling, problems with dosing of ingredients and high cost of ingredients.

The above-mentioned drawbacks are overcome by the Portland or slag-portland cement according to the invention made of clinker having a tricalcium silicate content above 56 wt. %, A guide surface of 250-1000 m ² .kg ^-1 Blaine, characterized in that it comprises the reaction product of triethanolamine and an aqueous solution of hydrochloric acid having a pH of 7.5 to 9.0.

The reaction product of triethanolamine with hydrochloric acid is prepared by mixing them together and then chemically reacting in aqueous solution in such a ratio that the pH of the reaction product is in the range of 7.5 to 9.0.

The advantages of the cement with increased initial strengths according to the invention are its high initial compressive and flexural strengths as compared to Portland or Slag-Portland cement with the same mineralogical composition and the same grinding fineness. All Portland clinkers can be used to produce the cement of the invention - it does not require special and expensive raw materials. The cement according to the invention can be produced without modification of the technological equipment and the technological process in each cement plant. The additive which is advantageously added when grinding the cement components acts simultaneously as a grinding intensifier and a cement liquor. Waste hydrochloric acid can also be used for its production. The additive has a corrosive effect on the steel reinforcement in concrete, is easy to handle, can be dosed well, its effect is higher than e.g. triethanolamine and is ceuove available.

The properties of cement with increased initial strengths according to the invention are shown in the following examples:

Example 1

PC 400 from SC Banská Bystrica, kp was mixed in laboratory mixer MCK 3 (content of tricalciumsilicate in clinker was 60% w / w, specific surface of cement 310 m ² kg ^-1 ), water and sand according to ČSN. Various additions of aqueous solution, an additive according to the invention with a dry matter content of 32% by weight, were added to the digesting water. A relative comparison of the initial strengths after 1 and 3 days is given in Table 1.

Table 1

Dose 32% Quantity · Relative strength of% dry matter additive bend pressure

ingredients '% to cement% 1 day 3 day 1 day 3 day 0 0 100 100 100 100 0.1 0,032 171 125 168 123 0.5 0.16 184 120 173 122 0.7 0,224 182 130 178 121 1.0 0.32 165 124 138 120 1.5 0.48 143 116 115 103

Example 2

In the laboratory mixer MCK 3 SPC 325 from Cement works Turňa nad Bodvou was mixed (tricalcium silicate content was 58% w / w, cement specific surface area 280 m ²⁾ .

.kg ^-1 ), water and sand according to ČSN. Various additions of aqueous solution of the additive according to the invention with a dry matter content of 32% by weight were added to the digesting water. The relative strengths of the initial strengths after 1 and 3 days are given in Table 2.

Table 2

Dose of 32% additive solution

Ψο

Amount of dry matter additive to cement

Relative Strength% Bending Pressure Day 3 Day 1 Day 3 Day '%

0 0 100 0.02 0.0064 134 0.05 0,016 158 0.1 0,032 172 0.3 0,096 178 0.5 0.16 185

100 100 100 157 126 162 177 148 163 183 145 158 190 161 168 230 159 239

Example 3

A Portland cement mill was ground on an operating cement mill containing 62% tricalcium silicate. Table 3

Dose 36% Quantity of dry matter additive solution% additive to cement

0

0.15 0.054

0.15 0.054

0.15 0.054

Cement with increased initial strengths according to the invention can be used in prefabrication, for grout assembly, construction of chimneys and tanks by sliding formwork,

The cement was ground without and with the addition of an additive according to the invention with a dry matter content of 36% by weight. The relative strength after 1 day is given in Table 3.

Relative strengths per 1% bending pressure

100 100 min 197 min 157 max 243 max 236

206 0 190 in unfavorable weather conditions, in concrete technology with cast concrete, will be used for reconstruction work during operation.

Claims (3)

Portland or slag-portland cement of increased initial strength, made of clinker with a tricalcium silicate content exceeding 56% by weight, with a specific surface area of 250 to 1000 m ² . kg- ¹ according to the invention, characterized in that it contains the reaction product of an aqueous solution of triethanolamine and hydrochloric acid having a pH of 7.5 to 9.0.