Experimental Research on High Temperature Resistance of Modified Lightweight Concrete after Exposure to Elevated Temperatures

Table 4

Appearance and spalling statistics of the concrete specimens after exposure to elevated temperatures.

Mix	Temperatures: °C	Appearance			Spalling statistics
		Colors	Cracks	Spalling	: %
NC	20	Slight gray	—	—	66.7
	400	Slight red	Scarce and local	Slight
	600	Dark red	A small amount of fine cracks	Medium
	800	Cinereous	Long and wide	Medium
	1000	Straw white	A large amount of long cracks	Heavy
	1200	Slight yellow	Numerous and random	Heavy
LWAC	20	Dark gray	—	—	100
	400	Dark red	Local microcracks	Slight
	600	Slight red	A certain amount of fine cracks	Medium
	800	Straw white	Long and wide	Medium
	1000	Slight yellow	A large amount of long cracks	Heavy
	1200	Soil yellow	Numerous and random	Heavy
PLWAC	20	Dark gray	—	—	25
	400	Dark red	Scarce and local	—
	600	Slight red	Few small shallow cracks	Slight
	800	Straw white	A certain amount of fine cracks	Slight
	1000	Slight yellow	Long and wide cracks at edges	Medium
	1200	Soil yellow	Large amount and located at edges	Medium
GLWAC	20	Dark gray	—	—	16.7
	400	Dark red	Unclear	—
	600	Slight red	Scarce and local	Slight
	800	Straw white	A small amount of fine cracks	Slight
	1000	Soil yellow	Long and wide cracks at edges	Medium
	1200	Brownish Yellow	Large amount and located at edges	Medium

represents the percentage of the specimens spalled when the target temperature was above 400°C.