Can I travel outside the United States with my existing travel/work combo card, while my renewal applications are pending?

Yes, in general an applicant for a green card may travel on an approved advance parole document for as long as that document is valid, meaning the applicant must re-enter the United States before the current advance parole document expires.

According to the U.S. Citizenship and Immigration Services’ (USCIS)  Emergency Travel overview, "If you file Form I-131, Application for Travel Document, to request an advance parole document and depart the United States without possession of an advance parole document that is valid for the entire time you are abroad, your Form I-131 will be considered abandoned. At times, an individual may have an approved advance parole document while a second one is pending. Individuals may travel on the approved advanced parole document, provided the document is valid for the entire duration of the time abroad. The pending Form I-131 will not be considered abandoned in this situation."