Introducing VOIDSPACE from Terracentric Materials, LLC, the preferred aggregate for PaveDrain Systems. Compared to quarried aggregates, VOIDSPACE increases water storage below PaveDrain Systems during rain events while meeting Total Maximum Daily Load (TMDL) limits for phosphorus for stormwater runoff.

VOIDSPACE is a high strength, lightweight, vesicular, synthetic calcium alumino-silicate aggregate which has a high internal and surface porosity that maximizes the water storage volume below PaveDrain Systems. Figure 1 shows the surface morphology and structure of VOIDSPACE and its composition is shown in Table 1. VOIDSPACE comes in two main sizes for use with PaveDrain, AASHTO No. 67 (VS1; upper layer) and AASHTO No. 3 (VS2; lower layer) as shown in Table 2 and Figure 2.

Phosphorus Removal Rates


Table 3 shows a summary of the bulk chemistry and the key compaction parameters of VOIDSPACE aggregates for use with PaveDrain Systems.

VOIDSPACE also has the ability to rapidly remove dissolved phosphorus from water in the time frames associated with stormwater storage in underground vaults (up to 72 hours). Duplicate equilibration experiments modeled after EPA 1316 using VOIDSPACE Aggregates (VS1 and VS2) and stock solutions with 1, 5 and 10 mg/L ortho-PO4 (most storm water has < 1 mg/L) for contact times between 5 minutes and 72 hours showed that the VOIDSPACE aggregates achieved very high removal rates of phosphorous, as shown in Figure 3.

VOIDSPACE fines (VSF; <3/8 inches) result from the aggregate crushing process to make VS1 and VS2 are also available and may have significant advantages when it comes to phosphorus removal when placed at strategic locations in the PaveDrain System profile. Figure 3 shows that VSF was associated with almost complete removal of ortho-PO4 for all contact times tested.

Design. Build. Supply.

The Convergent network partnered with PAVEDRAIN and Terracentric offers clients one stop shopping when it comes to porous pavements, increased water storage and phosphorus removal in a single application. We look forward to hearing from you.

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