Except with the written permission of the supervisor, mortar masonry construction shall not be carried out under the condition that the average day and night temperature is lower than +5℃ or the stone is frozen. All concrete and stone masonry shall be maintained in accordance with the relevant provisions of Sections 6.12 and 14.5 of Technical Specifications for Construction of Highway Bridges and Culverts (JTG/T F50-2011)