Data on the estimation of thermomechanical damage for fired clay bricks

Fired bricks are on high demand in building constructions because of their cheapness, appearance, robustness, isolation achievement and sustainability. To make fired bricks, Constructions and eco-friendly sector used clay materials. However, the major challenge in their utilization is their thermal and mechanical behavior after exposure. Problems occur mainly when permanently subjected to increased temperature which severely influence its durability, and in this case an overall failure mode calculation is essential. In this work a simple approach based on the Unified Strength Theory (UST) criterion was used to estimate the thermomechanical damage. Results of thermomechanical damage values are shown.

The thermogravimetric and thermal differential analysis (TG/DTA) was performed on the Automatic Multiple Sample Thermogravimetric Analyzer TGA-20 0 0. The chemical analysis of major elements (SiO 2 , Al 2 O 3 , TiO 2 , Fe 2 O 3 total, MnO, MgO, CaO, Na 2 O, K 2 O, P 2 O 5 , LOI) were assayed using a X-ray fluroescence ARL PERFORM-X 4200 spectrometer. The compressive tests were carried out on a universal testing machine of 20 0 0 kN. Data

Value of the Data
• This data can help to improve clay bricks production process through the definition of appropriate firing and operating/use temperatures. • This data can provide insight for studying the macroscopic response from damage propagation of the clay in the future. • This data can provide insights to an enhanced understanding of high temperature clay mechanics and provide the basis to improve clay bricks resource durability

Data Description
This article consists of tables and figures that depict data obtained from various tests among other the thermogravimetric and thermal differential analysis (DTA/TGA) ( Fig. 1 ), the X-Ray Diffraction (XRD) ( Fig. 2 ) for thermal and mineralogical analysis respectively of the clay used. Mineralogical analyses have also been made in order to identify the mineral phases ( Table 1 ). The database is composed of five Excel files that contain raw data ( Table 2 ). It includes data on thermogravimetric and thermal differential analysis (DTA/TGA), X-Ray Diffraction (XRD), thermal and mineralogical analysis, TM Damage values for the effect of the intermediate principal

Experimental Design, Materials and Methods
Clay from Nsimalen, a locality around Yaoundé (Cameroon), was selected because of its matter of development implementations [2] .
The thermogravimetric and thermal differential analysis (TGA/DTA) and the XRD have been undertaken to pinpoint its thermal behavior and mineralogical composition.
Approximately 1 g of material is collected and dried in the oven at 40 °C for at least 24 h. The sample is crushed manually with agate mortar and sieved dry to 250 μm until full passage. An aliquot is placed door by simple pressure in order to limit any preferential orientation of the mineral according to the method of Moore and Reynolds (1997). The resulting difractogram allows the identification of all reflections.     The perculiarity X-ray diffraction (XRD) high points were registered in the progression 2 °≤ 2 θ ≤ 70 °with a diffractometer Bruker Advance Eco outfitted with a Cu K α1 ( λ = 1,5418 Å ) irradiation generator. The ray generator was exploited at ambiant temperature with tension and current setting as 40 kV and 30 mA respectively.
The thermogravimetric and thermal differential analysis (TG/DTA) was conducted on the Automatic Multiple Sample Thermogravimetric Analyzer TGA-20 0 0 of AGES in an intense airing environment at a warm-up speed of 5 °C/min for 25 ~10 0 0 °C ± 1 °C temperature on Nsimalen samples (0.1-1.5 g).
The clay was crushed in a grinder and sieved at 800 μm. Then, the test brick slip were formed as conventional cube-shaped of 4 × 4 × 4 cm operating with combined clay and suitable amount of water (approximately 20% on dry basis) to fulfill right usability. The realized cubes were first desiccated at atmospheric environment for 72 h and positioned in an oven at 105 °C for 24 h for an entire elimination of hydrating water, before being fired in a smoother boiler up to 1050 °C. Five temperatures, to which the samples laid in the furnace are warmed up, were selected: 95, 200, 550, 700 and 950 °C. The compressive tests were accomplished on a universal testing machine of 20 0 0 kN according to ASTM C67-80a standard. The tests were undertaken at a steady rate of motion of 5 mm/min to obtain the absolute stress -strain curves. An equally dispersed and continuously growing charge was required up to specimen breakdown, on cross-sectional sides portrayed by the width and the depth of the brick (4 × 4 × 4 cm).
With σ i j is the stress component, -ε i j is the strain component, -ε th is the thermal strain component, -ζ is the adjustment factor -μ is the ratio due to the behavior of clay at elevated temperatures -E T is the modulus of elasticity at temperature T -W is a Weibull parameter that specifies the constraint level of the submicroscopic constituent, -W 0 ( the scope ratio corresponding to the submicroscopic constraint component part ) and m (the scope ratio determining the amount of regularity) are the statistical parameter used in the Weibull distribution.
Graphs were produced using Excel after testing functions that could fitted the data obtained.The functions that fitted the data are given by Eqs. (2) and (3) for normalized W and normalized m respectively.

Declaration of Competing Interest
The authors sincerely thank the Local Materials Promotion Authority (MIPROMALO) in Cameroon for its collaboration in making available the samples used for this study. They equally express their gratitude to the National Civil Engineering Laboratory (LABOGENIE) in Cameroon and the Laboratoire de l'Unité de Recherche Argiles, Géochimie et Environnements sédimentaires (AGEs) de l'Université de Liège where all the tests were carried out.