**3. Tebbal et al.'s research on the effect of temperature on high-performance concrete**

This study examines the effect of the additions of silica fume and super plasticizer on the mechanical performance of high-performance concretes at high temperatures. The tested concretes are formulated with 5% silica fume and two dosages of super plasticizers in the ratio of (2%, 2.5%) the weight of cement after having been exposed to four maximum temperatures, 200, 400, 600, and 900°C, without any imposed

**111**

**Table 1.**

SiO2 Al2O3 Fe2O3 CaO MgO SO3 CL

*Mechanical Behavior of High-Performance Concrete under Thermal Effect*

• The influence of super plasticizer on the mechanical strength

• The additions of silica fume on the behavior of HPC

The chemical composition of the cement is shown in **Table 1**.

load during the heating. The results obtained show that the mechanical resistance at 28 days increases with the degree of temperature compared to that measured at 20°C. On the contrary, a clear decrease is observed between 600 and 900°C. However, material composition seems to have great influence on the mechanical strength. In the present study, three factors were studied at high temperatures:

• The internal structure, X-ray diffraction (XRD) patterns and gravimetric and differential thermal analyses (ATG and ATD) of concrete subjected at high

The portland cement-type CEM II/A 42.5 from Hammam Dalâa local factory was used in this experimental study. The used cement type has an absolute density,

The silica fume is obtained from GRANITEX in Algeria region. It results from melting the silicon and ferrosilicon. The reduction of high-purity quartz to silicon at temperatures up to 2000°C produces SiO2 vapors, which oxidize and condense in the low-temperature zone to tiny particles consisting of noncrystalline silica [39]. The physical properties and particle size by laser granulometer (Mastersizer 2000)

The natural fine aggregates used were dune sand with particles ranging from 0.08 to 5 mm in size, with a fineness modulus, Mf, of 2.44. This natural sand was

> 20.7 04.75 03.75 62.92 01.90 1.98 —

Item content C3S C2S C3A C4AF

Super plasticizer Form Color PH Density Chlorine

<0.1 microns <0.5 >15 m2

*The chemical and physical properties of cement and silica fume [18].*

Particle size Density Specific surface Moisture by storing

Medaplast SP40 Liquid Brown 8.2 1.2 ± 0.01 <1 g/l 40%

59 14 6 10

, 28%, and 4000 cm2

**Cement (%) Silica fume (%)**

/g, respectively.

>85 — — — — <2.5 <0.2

at 105°C

Dry extract

/g <1%

content

*DOI: http://dx.doi.org/10.5772/intechopen.89916*

temperature

**3.1 Materials and methods**

consistency, and fineness values of 3.1 g/cm3

of silica fume are shown in **Table 1** and **Figure 1**.

Mineralogical composition of cement

Physical properties of silica fume

Characteristics of the chemical admixture

load during the heating. The results obtained show that the mechanical resistance at 28 days increases with the degree of temperature compared to that measured at 20°C. On the contrary, a clear decrease is observed between 600 and 900°C. However, material composition seems to have great influence on the mechanical strength.

In the present study, three factors were studied at high temperatures:

