DE2259274A1 - Pumice powder-contg hydraulic binder - consisting of up to one third ground lava powder and balance portland or other cement - Google Patents

Abstract

Homogeneous hydraulic binder mixt contains Portland cement or similar and a ground, SiO2-contg additive consisting of pumice powder and making up =1/3 wt. of mixt. Strength of concrete end-prod. is higher than that obtd with volcanic tuff cement. Main mineral component of pumice powder was diopside, with amts of magnetite and perovskite.

Description

Hydraulic binder with a homogeneous mixture of Portland cement Or the like. And a ground, silica-containing additive.

The invention relates to a hydraulic binder with a homogeneous Mixture of Portland cement or the like and a ground silica-containing additive.

In a known binder of a similar type, the additive consists of Trass. According to the cement paperback 1968/1969, p. 48, this trass cement is used very special purpose, namely to improve the workability and water resistance of the concrete.

The invention is based on the object of the hydraulic binder of the type mentioned to choose an additive with which the proportion of Portland cement or the like. Can be reduced in the mixture and with the higher strengths than can be achieved with trass cement in the end product.

This object is achieved in that the additive is formed from lava flour is, the weight proportion of which in the mixture is up to about one third.

This has the advantage that the expensive to manufacture and therefore relatively expensive Portland cement is partially replaced by lava flour, what leads to considerable savings. Compared to the trans cement, the binder brings according to the invention the further advantage that the required strength is far exceeded wrd. The same advantages occur if the binder is a Portland cement similar cement is chosen.

During production, dried lava sand (e.g. 25 Percent by weight) mixed with the cement clinker and ground with this.

Based on test results of some with the binder according to the invention produced test specimens, the invention is to be explained in more detail.

The lava flour was determined in duplicate after drying at 110.degree chemically analyzed. The loss on ignition was carried out at 10500C.

Analysis inventory Part I Part II Mean (% by weight) (% by weight) (% by weight) Loss on ignition 4.66 4.50 4.58 SiO2 39.90 39.91 39.91 AL2 ° 3 12.70 12.84 12.77 TiO2 2.71 2.78 2.74 Fe2O3 11.20 11.11 11.16 CaO 15.00 15.00 15.00 MgO 8.10 8.07 8.08 Na2O 1.24 1.27 1.26 K2O 3.49 3.50 3.49 SO3 0.04 0.04 0.04 P2O5 0.81 0.81 0.81 CL 0.009 0.011 0.01 99.859 99.841 99.85 The mineral composition was determined by an X-ray diffraction analysis certainly.

Diopside was found to be the main mineral. In addition, could Magnetite and a small amount of perovskite can be detected. Nikroscopic Investigations revealed a larger proportion of glass phase.

Such a lava meal sample is of the mineralogical composition to be described as compatible with cement. The chloride and sulfate levels are far below the limits specified in DIN 1164. The high MgO content is in the diopside (CaO.MgO.2SiO2) or bound in the glass portion and cannot lead to malfunctions.

The alkalis are also bound in the glass.

The average density was 2.972 g / cm3.

The strength tests were carried out in accordance with the standard DIN 51043 carried out. There were mortar mixes of 0.8 parts by weight of lava, 0.2 parts by weight Lime hydrate (95% Ca (OH) 2), 1.5 parts by weight of standard sand and a 1 <water / binder value = 0.45 established. The measured strengths are in the table below compiled.

Compressive and flexural strengths of lava flours Lava flour Age Weight ßß ßßm ßD ßDm AB (Tg) (g) (kp / cm2) (kp / cm2) (kp / cm2) (kp / cm2) (cm) 549 16 74/73 7 549 19 18 72/72 73 549 18 72/73 1.Lower- 555 34 130/132 lützingen 28 556 31 32 125/130 128 I 550 31 128/124 16.0 547 36 135/138 56 550 33 34 132/132 134 545 33 132/138 547 34 141/141 90 541 38 37 141/147 140 551 40 135/138 547 15 59/16 7 547 16 16 64/61 61 545 17 60/61 555 33 114/115 2nd lower 28 550 34 34 119/118 116 lützingen 552 35 120/112 13.0 II 565 32 123/126 56 562 32 33 126/80 125 563 35 126/123 558 38 141/147 90 570 41 40 138/141 142 566 41 141/144 547 6 20/21 7 549 6 6 22/21 21 542 6 21/21 3rd low 556 28 77/74 lützingen 28 559 28 28 74/73 74 III 557 27 73/75 7.0 556 31 98/80 56 555 30 30 80/83 85 554 30 92/77 561 | 34 95/98 90 553 | 35 35 92/77 95 560 | 35 92/98 After 28 days, the Niederlützinger Lava reaches compressive strengths of 74, 116 and 128 kp / cm2, whereby it exceeds the minimum value of 50 kp / cm2 after 28 days, which is required for Traß according to DIN 51043. After 90 days values of 95, 142 and 140 kp / cm2 are achieved.

The investigation of the water solubility in the lava flour found P205 resulted in the following: 20 g of lava flour were taken from the sample of lava flour delivered, 200 ml of H20 are added and the mixture is stirred for 6 hours in a water bath while warming to 1000C. It was then made up to 200 ml, centrifuged and in 100 ml after acidification the dissolved P2O5 is determined with the addition of HNO3 and ammonium molybdenum. There were 0.001 wt.% P @ O5 25 found.

The result shows that the phosphate, which is wet-chemically with 0.81 wt.% was determined, is essentially insoluble in water in the glass portion of the lava flour. It can therefore have no noticeable influence on the setting and hardening of the cements exercise.

Furthermore, bending tensile testing was carried out by an officially recognized testing institute. and compressive strength tests carried out. With a standard cement-lava flour mixture from 75:25 v.H.

The proportions by weight (mixture of 33715 g cement and 112.5 g lava flour) and standard storage resulted in the following values: flexural tension, compression, specimen weight strength strength Sample test at the individual iM individual iM old evaluation values switch fen No. days gg kp / cm2 kp / cm2 kp / cm2 kp / cm2 1 2 552 553 25 88 2 552 554 24 88 3,550,552 25 24 86 87 1 7 549 553 50 228 2 551 555 53 233 3 551 555 50 51 231 231 1 28 552 559 68 385 2 552 559 73 376 3 549 556 72 71 372 378 1 56 556 567 82 459 2 552 563 77 447 3 552 562 75 78 444 450 With this test result it is established that the examined hydraulic binding agent (see patent claim) fulfills the requirements for a cement of the skill class Z 350 L according to DIN 1164.

Claims (1)

P a t e n t a n s p r u c h: Hydraulic binder with a homogeneous mixture of Portland cement or the like and a ground, silicic acid-containing additive, characterized in that that the additive is formed from lava flour, its weight proportion in the mixture up to is about a third.