An estimated 400 people gathered for "spontaneous protests" in the port city on Monday, according to Al Jazeera.
The death toll from the explosions has now risen to 114, with dozens still missing.
Al Jazeera's Adrian Brown, reporting from Tianjin, said that dozens of soldiers looked on as the protesters gathered, making no attempt to stop them, nor the local journalists covering the event.
Residents said they were not aware that dangerous chemicals were being stored in the port.
Chinese state-run media have also lambasted officials for a lack of transparency over the massive explosions.
The editorials and commentary pieces published on Monday echoed frustrations voiced by the public over the slow release of information in the aftermath of the August 12 explosions.
Authorities in Tianjin have faced criticism over failing to uphold regulations surrounding the site's operation, notably requirements that warehouses stocking dangerous materials be at least one kilometre from surrounding public buildings and main roads.