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Abstract-Limestone and claystone are widely used in rocky mountainous areas as building materials in Kurdistan region, in particular, the city of Koya. The outbreak of fire in buildings will have a great impact on strengths of building materials. The property performance of these local materials is understudied. This research investigates the impact of high temperature on the physicomechanical properties of limestone and claystone from Fatha Formation in Koya in Kurdistan region of Iraq. For this purpose, cores were taken from intact rocks; their ends were cut by a mechanical saw to obtain a cylindrical shape and immersed in water for 24 h, and then, subjected to physicomechanical tests of specific gravity, water absorption, porosity, and uniaxial compressive strength. For determining the residual compressive strength, the specimens were taken out from water, surface dried, and exposed to high temperatures of 450, and 650°C for 2 h using an electric oven. The results showed that claystone specimens show more stable mechanical properties than the limestone after exposure to high temperatures, and the high temperature causes lightening in color and significant cracks in both materials.

The Marshall Mix design is one of the most widely used methods for designing and evaluating hot asphalt mixes globally, and the main Marshall Test focuses are stability and flow. Two standard curing methods are normally followed to elevate the temperature of testing samples; these involve immersing the samples in 60°C water or placing the samples in an oven at 60°C. These standard curing methods may not simulate the actual state of heating of asphalt pavement in the field, however. In this research, a new curing method that includes insulating the samples before immersion in hot water is thus introduced and compared with the two standard curing methods. During immersion, the water temperature is increased to 60°C and the core temperature of the insulated samples determined. Three sets of Marshall Samples were prepared and cured using the outlined methods; each set consisted of 18 specimens of 101 mm diameter and 63.5 mm height. All specimens were tested using the Marshall Test for stability, flow, and Marshall Stiffness. The set mean results showed that the oven cured samples demonstrated the highest stability values, followed by the standard water cured samples, while the insulated samples exhibited the lowest stability values. The oven cured samples also exhibited higher Marshall Stiffness Index (MSI) values than the other curing methods. However, one-way ANOVA (single factor) testing demonstrated that these differences were not statistically significant.

The Pila Spi Formation is one of the prominent formations forming continuous ridges in Kurdistan Region. The thickness of the formation ranges from 15 to 110 m, consisting of well-bedded limestone, dolomite, dolomitic limestone, and very rare marl beds. The study area is located about 15 km east of Koya town, next to the abandoned tunnel through a deeply cut valley which has exposed 50 m of the formation. However, the uppermost part of the exposed section may belong to one of the Oligocene formations of Kirkuk Group. The study area was selected within the Pila Spi Formation because the rocks of the same formation and along the same ridge, about 45 km west of the study area showed encouraging results for cement industry. The average CaO is about 51%, whereas the average MgO is 1.8%. Therefore, eight samples were collected at constant thickness from the exposed section. The samples were subjected to X-ray fluorescence (XRF) test to indicate the main oxides in the sampled section. The acquired results from the XRF tests showed that the chemical composition of the exposed rocks within the Pila Spi Formation is suitable for cement industry, also for paper and paint but needs some treatment. Accordingly, another eight samples were collected from the same section to increase the density of sampling, totaling to 16 samples.

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