Allu has now placed its two solutions side by side to provide demolition sites with increased capacity.

When first tested by a Finnish customer, the crusher and screener combination, operating side by side, was reported to have made a dramatic improvement. At the site, 85% of material was screened and also partially crushed through a screener-crusher bucket (Allu Transformer DH 3-17 XHD) with only the excess very hard material being crushed with a  crusher bucket (Allu Crusher AC 25-37). “The demolition concrete was treated after pulverisation with two Allu’s.  The excess obtained from the screener-crusher bucket was crushed to a 90mm fraction with a crusher bucket. Thus, a total of about 5,000t passed through two buckets. 

“The demolition of two, two story residential buildings produced a total of about 5,000t of concrete. The maximum fraction size achieved in the pulverisation was 400mm, which is a maximum good input feed size for the Allu crusher bucket. The jaw is reversible, which enables fast and easy recovery from possible blockages. In my 30 years in the industry this has changed the direction for demolition,” said Ilpo Ellonen, regional sales manager, Allu Finland Oy.

The demolition took a total of three weeks. At the time of the visit to the site, approximately 700t of concrete waste were still untreated. Some of the crushed concrete will be used at the bottom of the forest road, with the purpose of the (crushing and screening) process being to recycle concrete waste into stone aggregate for reuse. This will then replace the need to use (and buy in) virgin aggregate, providing an environmentally sustainable solution. 

Allu states that the throughput of material from the screener-crusher bucket is many times higher than solely with the crusher bucket. Hence the goal at the Finnish demolition site was to extract fines out as accurately as possible by screening so that the amount of material to be crushed is kept to a minimum. The screener-crusher bucket was fitted with a basic block type drum with a 75mm hammer configuration which Allu states removes the requirement for more expensive hammer options.