FORSCHUNGSVEREINIGUNG KALK-SAND E.V./TU CLAUSTHAL

Use of natural heavy mineral sands
for increasing the gross dry density
of calcium silicate units

1 True densities of employed mineral aggregates

2 Grain-size distributions of mineral sands

3 Grain-size distributions of heavy mineral sands

4 Comparison of calculated packing densities

5 Light-optical micrograph of specimen R2

6 Light-optical micrograph of specimen W2

7 Light-optical micrograph of specimen R27

8 Light-optical micrograph of specimen W11

9 Detail image of a barite grain from specimen R25

10 Detail image of a barite grain from specimen W9

11 Image of specimen W15 obtained with parallel polarizers

12 Image of specimen W15 obtained with crossed polarizers

13 Detail image of specimen W15 obtained with parallel polarizers

14 Detail image of specimen W15 obtained with crossed polarizers

15 Detail image of an olivine from specimen W16 obtained with parallel polarizers

16 Detail image of an olivine from specimen W16 obtained with crossed polarizers

17 SEM-micrograph of a barite grain from specimen WVW2

All authors

This AiF project enabled experimental demonstration of the fact that natural, heavy mineral sands can be used as raw material for calcium silicate unit specials of very high gross dry density. The products in question are exclusively intended either for satisfying very stringent sound insulation requirements or for radiation shielding purposes.

1 Introduction

Commercial-grade calcium silicate units are produced from lime, natural mineral aggregates and water in a process called hydrothermal curing. Also referred to as steam curing, the process combines partially dissolved mineral-aggregate silica and the available hydrated lime calcium-silicate hydrate (CSH) phases that solidify the sand to a level of strength also defined by their grain-to-grain contact forces. Modern construction requires building bricks of high gross dry density for acoustic insulation purposes, and conventional calcium silicate unit products serve that purpose...

TEXT Dr.-Ing. Wolfgang Eden¹ (Lead researcher), Dr.-Ing. Claudia Eichhorn²
(Senior researcher), Prof. Dr. rer. nat. Albrecht Wolter²(Director)
¹Forschungsvereinigung Kalk-Sand e.V., Hanover/Germany
²Clausthal University of Technology, Clausthal-Zellerfeld/Germany

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