Cement manufacture causes environmental impacts at all stages of the process.
The fact that Granulated Ground Blast-furnace Slag (GGBFS) isn’t quarried and baked before it comes to Vallejo is beside the point.
The salient question is whether shipping slag from Asia on ships using diesel engines, grinding and mixing it here, then shipping the products using nearly 600 truck trips a day is appropriate for a densely populated residential neighborhood, passing by our schools.
To focus on whether this final product is actually green is just a distraction.
We agree that GGBFS cement is better than Portland cement. But better doesn’t mean it’s good.Please share !
What is green cement? ORCEM’s answer:
Orcem’s green cement – or GGBFS – is produced by grinding specially processed blast-furnace slag and mixing it with small amounts of gypsum and other supplements to adjust setting time. Green cement not only uses recycled material as its ingredients, but also produces stronger, more durable concrete. It only requires a small amout of energy for drying and milling, which specifically reduce greenhouse gas and other combustion emission in comparison to its alternative, portand cement.
What is green cement? The rest of the story:
GGBFS uses waste slag, a byproduct of steel production. Substituting GGBFS for ordinary limestone clinker reduces the overall carbon footprint by eliminating the need for quarrying and baking limestone in high temperature kilns. How much of that savings is nullified by loading GGBFS produced in Asia onto polluting heavy cargo vessels and hauling it across the ocean? Cement manufacture causes environmental impacts at all stages of the process. The fact that the GGBFS hasn’t been quarried and baked before it comes to Vallejo is beside the point. The salient question is whether this site is an appropriate place for heavy polluting industry in 2016 Vallejo. The focus on whether or not you can justifiably call the final product green cement is a distraction.