Selecting the right grade of sand appregiate

Stone, of course, normally takes pride of place as the most prominent and admired natural building material because of its prominence, charm, antiquity and strength through the ages. And pointing can have a substantial impression not only on the charm and appearance of traditional surfaces, but also upon their well-being and longevity. A important initiating point for good procedure in traditional preservation and the restoration and renewal of plasters and renders must be to get the mortar mixes right in terms of diagnosis, size, specification, procurement, site preparing and inclusion. During the Roman phase, for example, Vitruvius published in his manuals on structures, 'in walls of masonry, first question must be with respect to the sand, in order that it may be appropriate to blend into mortar and have no dirt in it. The kinds of pit sands are these-black, grey, red and carbuncular.
Purchases of lime and sand for building in the Middle Ages among the commonest entries in surviving building accounts. At Dover Castle in 1226 for example, the digging, sieving and carrying was on a very large scale with documentary entries reporting 11,000, 160 seams of sand obtained for £9.10s.8d, and another for £10.10s paid for 11,000 (loads) of sand, on account of the goodness of the winter season, presumably our reference to sea-sure quarrying with winter rains washing out a certain amount of the sea salt which makes the aggregate otherwise so unsuitable for building purposes. Quality control, it is understood, has always been an issue for the building trade. The United Kingdom's current demand for aggregates forcible engineering and construction, including road works, concreting etc, comes to more than 250 million tonnes per year. Of course, we know this is not to be the case. Consequently there has been an equal and opposite development of interest more recently in lime-based materials. But the focus remains on the binders in the literature and on site.
The balance of knowledge and experience therefore no need to be re-addressed. It is difficult to establish when the term 'aggregate' was first used. Purpose the most immediately obvious benefit of use of aggregate is that it conserves the comparatively expensive binder and usually forms the greater part of the finished material. Its use can, however serve a very important function in tempering the qualities of the binder to allow for the sympathetic coexistence (thermal and moisture movements, porosity and permeability) of the material within masonry. A further important consideration is the influence that the aggregate can have on the colour and texture of the material: indeed this can sometimes be an understandably will unwisely over-riding factor in aggregate choice. However, the specification of the sand for these other uses, especially the particular size, shape and chemistry, is often very specific and is not necessarily compatible with that required for construction purposes. When using pigments to achieve a specific coloured appearance, it should also be remembered that the two will add to the total fines content of the aggregate grading.
Certain additives which increase the quantity of aggregate in the mortar mix, especially at the fines end of the grading curve, will not be discussed here. 'Sands' are therefore composed of the loose, detrital, granular material which results from the breakdown of rock by wind, rain, temperature changes, rivers, glaziers and the actions of plants and animals, in what has been termed the recycling of rock. 'Sharp sands' may be highly quartzone and contain grains which are literally sharp due to their angular nature. In contrast, 'soft sands' are quite rounded, having been transported fonder and therefore having had a longer time to become abraded. Mineral constituents will inevitably affect the properties and performance of many sands in use.