Cement-based Building Materials Research Articles

Self-Cleaning Cement-Based Building Materials

The modern rhythm of human life leads to well-known problems, which are air, water and soil pollution and climate warming. An increase in the power of industries and vehicles leads not only to atmospheric pollution by-products of incomplete fuel combustion but also to various microscopic particles that form aerosols, which carry an obvious danger to human health and also pollute the buildings’ facades. An environmentally friendly building material with a hybrid method “Nano-titania gradient” was developed. This method consists of forming a gradient of n-TiO2 particles concentration in the composite since the physical properties of the composite are always inextricably linked to the geometry. To increase the efficiency of the photocatalytic process, a method of surface sensitization of titanium dioxide with the use of graphene oxide was proposed, which contributed to an increase in the overall photosensitivity. Thus, the decomposition of nitrogen oxide by volume with the modified surface increased by 27% in comparison with the classic titanium dioxide, and the decomposition of volatile organic substances increased by 32%. It was found that for the facade plate made with surface-sensitized TiO2, the process of self-cleaning is completed after 3 h after the irradiation start. The modern rhythm of human life leads to well-known problems, which are air, water and soil pollution and climate warming. Using the theory of percolation, the concentration range of the photocatalyst content was calculated. To facilitate the material, waste cellulose was introduced. To increase the efficiency of the photocatalytic process, a method of surface sensitization of titanium dioxide (SS TiO2) with the use of graphene oxide was proposed. The analysis of the experimental-statistical models of the compressive strength shows that the optimum content of TiO2 was in the range from 0.8 to 1.1%, and cellulose from 0.4 to 0.8%, the optimum content of SS TiO2 was in the range from 0.7 to 1.1%, and cellulose from 0.4 to 0.8%. Analysis of the experimental and statistical model of the bending strength shows that the optimal content of TiO2 and SS TiO2 was in the range of 0.6 to 1.0%, and cellulose from 0.4 to 0.8%. When studying the structure of composites, it was found that titanium dioxide was sorbed on the surface of swollen cellulose fibers and remained there after the process of cement hydration. The effectiveness of the method of surface sensitization of titanium dioxide by combining it with graphene oxide was shown. Thus, the decomposition of nitrogen oxide by volume with the modified surface increased by 27% in comparison with the classic titanium dioxide, and the decomposition of volatile organic substances increased by 32%. It was found that for the facade plate made with surface-sensitized TiO2, the process of self-cleaning was completed after 3 h after the irradiation start.

Effects of citrate acid, solidum silicate and their compound on the properties of magnesium oxysulfate cement under carbonation condition

Additives including sodium silicate (SS) and citrate acid (CA) have been used to modify magnesium oxysulfate (MOS) cement. To improve the durability of modified magnesium oxysulfate (MMOS) cement and widen its application under carbonation environment, this paper reports experimental investigations into the mechanical properties, microstructural characteristics, and porous structure of MOS cement modified by CA, SS and their compound of CS by accelerated carbonization test. The properties were examined by mechanical strength tests, evaporable water test, X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and thermogravimetry (TG). Comparing to uncarbonated MOS and MMOS cements, 28 days of carbonation reduced the flexural strength by 20%-50%, and the compressive strength of cements modified by CA or CS was increased by 5%. Both CA and SS significantly improved the strength of carbonated or uncarbonated MOS cement, and CA required fewer time to achieve the mechanical strength similar to CS. Carbonation grated more MgCO3 and refined the porous structures of cement paste by reducing total pore and large pre. CA or CS at least reduced the brightness MOS cement paste by three times, whether they were carbonated or not. Microstructural analysis of samples collected in different carbonation depths further explained the modification mechanism from chemical composition perspectives. Finding of this study provide insights into the design of high-performance and sustainable MOS cement-based building materials under carbonation environment.

Environmental Benefit of Alternative Binders in Construction Industry: Life Cycle Assessment

Carbon dioxide (CO2) emissions associated with Portland cement (PC) production is ranked as the highest among the construction materials and it is estimated that 8% of the worlds CO2 discharges is due to PC production. As an average, the production of PC clinker including calcination process generates 0.81 kg of carbon dioxide per one kg of cement. Hence, new approaches which limit the negative environmental impacts of cement production and are aimed at the development of advanced methodologies are introduced. Implementation of lower energy consumption materials in production, which could moderately substitute PC in binders, can be addressed as one of the probable methods in mitigating environmental risks. Therefore, alternative binders fit into the most promising solutions. Present research investigates the environmental impact of the building sector, if an alternative to PC binder is used. Life cycle assessment (LCA) was used in this research to assess the environmental impact of the alternative ternary gypsum-PC-pozzolan binder in the production of mortar, and the environmental benefits were calculated and compared to traditional cement-based building materials. Phosphogypsum was considered as a secondary raw material, as in the current approach it is collected in open stacks bringing environmental concerns. SimaPro LCA software with the Ecoinvent database was used for most of the calculation processes. Results indicate that with alternative binders up to 30% of energy can be saved and 57 wt.% of CO2 emissions can be reduced, bringing positive impact on the construction industries contribution to the environment.

Recent progress in superabsorbent polymers for concrete

Scientific interest on superabsorbent polymers (SAPs) in conjunction with cement-based building materials has widened from mostly engineering aspects towards polymer physico-chemical topics over the past years. Here, we focus on the relationships between absorptivity in terms of absorption/desorption kinetics and retention of the absorbed liquid and the polymer physico-chemical principles. Based on such understanding, use and effects of SAPs in concrete are outlined and explained mechanistically. They comprise modifying rheology, internal curing to mitigate plastic and autogenous shrinkage, self-sealing and self-healing of cracks, and improvement of freezing-and-thawing durability. Recent topics such as reduction of fire spalling and enhanced growth of plant species on green wall facades are also explored for advancing the applications of SAPs in cement-based materials.

Treatment methods for plant fibers for use as reinforcement in cement-based materials

The use of natural fibers in cement-based building materials has become an emerging field in the building and construction industry. Natural plant fibers are green, sustainable, and low-cost renewable resources that can be found in all parts of the world. Besides their biodegradability, studies have also established that the natural fibers also positively impacted the mechanical properties of the resulting composites. However, their utilization has also presented some challenges due to their high-water absorption, limited tensile strength, and open surface morphology that is exposed to cement hydration products and microbial degradation. Also, the fiber-cement matrix bonding and adhesion is another challenge limiting natural fiber utilization. Successful research on these challenges has been conducted and improvements were observed for the fiber-matrix adhesion and durability. Thus, herein we critically review the articles, discuss the science behind the treatment methods and suggest some intriguing issues for further investigation.

Microstructure Stability and Thermal Resistance of Ash-Based Geopolymer with Sodium Silicate Solution at High Temperature

Current cement-based building materials have a huge disadvantage that they are easily broken due to thermal decomposition at high temperature (over 500°C) of structures of hydrated cement. This is easily observed at construction works when burned, the cement-based mortar and concrete materials and plaster are susceptible to collapse causing damage to buildings or structures. More seriously, these accidents easily cause injuries or loss of life for residents and people working there. Therefore, research on fire resistance and structural stability at high temperatures of building materials is always an interested topic of many scientists. This study utilized resources of highly active alumino silicate materials such as coal bottom ash and rice husk ash to produce geopolymer using sodium silicate solution as an alkaline activator. The ash-based geopolymer has good engineering properties responding to requirements of ASTM C55 and C90 for lightweight concrete brick. It is interesting to note that the geopolymer product was tested for thermal properties at 1000°C such as heat resistance, volumetric shrinkage, mass loss. The experimental results show that the ash-based geopolymer material has high thermal stability with increasing significantly of compressive strength after heated at 1000°C. Moreover, the geopolymer was also carried out to characterize microstructure before and after exposed at high temperature using methods of X-ray diffraction (XRD), scanning electron microscope (SEM). Thermal analysis methods such as thermogravimetric (TG), differential thermal analysis (DTA), and dilatometry-thermal expansion (CTE) were used to evaluate microstructural stability of the geopolymer-based materials.

Thermal properties of calcium sulfoaluminate cement-based mortars incorporated with expanded perlite cured at cold temperatures

Reducing the thermal conductivity of cement-based building materials can alleviate the energy consumption and carbon dioxide (CO2) emissions that are related to space heating in buildings. The objective of this study is to incorporate expanded perlite into calcium sulfoaluminate (CSA) cement-based mortars to develop a novel building material that has low thermal conductivity for applications in cold regions. These mortars were cured at 23 °C and cold temperatures (0 °C and −10 °C), and experiments were conducted for thermal properties (i.e., thermal conductivity, thermal diffusivity, and heat capacity), unconfined compressive strength (UCS), density, ultrasonic pulse velocity (UPV), and thermogravimetric analysis (TGA). The results showed that CSA cement-based mortars gained UCS rapidly even at −10 °C owing to a fast hydration reaction, and an exponential decrease was found in UCS with an increase of the aggregate replacement ratio by expanded perlite. Thermal properties of CSA cement-based mortars were mainly affected by aggregate replacement ratios, while curing temperatures and ages had a negligible influence. For example, thermal conductivity decreased exponentially from 0.97 ± 0.01 to 0.13 ± 0.002 W/mK when the aggregate replacement ratio increased from 0% to 100%. It is of note that the thermal conductivity of CSA cement-based mortar without expanded perlite was 0.97 W/mK, being 47% lower than that of ordinary Portland cement-based mortar (1.83 W/mK). In summary, incorporating expanded perlite into CSA cement-based mortars reduced their thermal conductivity, showing their huge potential as energy-efficient and environmentally-friendly building materials.

Phase composition of CO2-hardened cement in the presence of chloride ions

Recently, the scientific community pays a great attention to CO2-hardened cement-based binders. This article considers the possibility of CO2 gas industrial waste using as a hardening environ in the process of cement-based building materials production. Some theoretical thermodynamic calculations was obtained to solve this question. It was found that the carbonation of hydrated cement occurs in the presence of a liquid phase. It is shown, that hydrated cement interact with both gaseous CO2 and CO32– ions in solution. The thermodynamic calculations made it possible to predict the most probable reactions at temperatures of 273,15 and 298,15 K. It was established some cement’s hydrates transformations under various conditions. It is shown that the CO2-hardened cement phases are more stable in the chloride solution.

Sarooj mortar: From a traditional building material to an engineered pozzolan -mechanical and thermal properties study

Developing new energy efficient building materials to reduce the carbon footprint is now the core of sustainability in construction and an essential factor of life cycle assessment (LCA). The extensive and increasing usage of conventional concrete, mortar, plasters and various cement-based materials is only one of the many factors contributing towards urban thermal discomfort caused by urban heat island phenomena and the poor thermal insulation of ordinary cement mortar. Not only this, the wide use of concrete and mortar in construction increases the consumption of their primary components mainly -Portland cement-requiring a large consumption of energy and causing a significant rise in CO2 emissions.Embedding natural and artificial cementitious/pozzolana materials in today's cement-based building materials has become a common practice. Cementitious and Pozzolanic materials are known to provide an added value to mortar/concrete not only in terms of mechanical and durability properties but also in energy efficiency and enhancing sustainability. Sarooj is a local term describing an artificial cementitious and pozzolana material obtained by traditional calcining of the raw clayey soil. Although its usage is nowadays very limited, Sarooj has been used in Oman and other neighboring countries for centuries, in various buildings and defense structures. The main objective of this research is to transform the traditionally produced Sarooj into an engineered binding material and hence investigating its physico-mechanical and thermal properties. The raw soil used to produce the traditional Sarooj was employed to engineer a modern “Sarooj” under controlled energy processing (grinding and calcination) conditions. The raw clay minded from specific location was ground first to a fine powdered material and then subjected to full characterization. The physical and chemical characterization indicated that the raw soil is suitable for producing a cementitious/pozzolanic calcined clay. The thermogravimetric and differential thermal analysis of the clay used reveal that only a moderate temperature of around 800 °C is required for its calcination which preserves energy and reduces CO2 emissions compared to 1600 °C to produce clinker cement. The strength development showed a slow early-age reactivity but an appreciable enhancement in long-term which demonstrates a remarkable latent hydraulic potential of the clay used. It was also found that adding an optimum amount of the calcined clay enhances the thermal properties. The annual energy performance of a typical housing in the hot climate of Muscat, Oman, was evaluated using DesignBuilder software, a whole-building simulation tool. The simulation results showed insignificant savings in annual energy consumption when the developed mixes are used as plastering materials. The clay alkali-activated with NaOH has, however, showed great potential to enhance the mortar's long-term strength. Using locally engineered cementitious material in a partial replacement of Portland cement can further enhance durability and sustainability by reducing the manufacturing energy of the produced building material such as mortars and plasters.

Life cycle assessment of the ornamental stone processing waste use in cement-based building materials

Laboratory technical studies demonstrate the feasibility of using the ornamental stone processing waste (OSPW) for construction and building materials manufacturing. However, regarding the environmental aspect, there is still the need to justify its use quantitatively. Thus, this study presents the life cycle assessment (LCA) of using OSPW for cement-based building materials manufacturing, aiming to assess OSPW influence on environmental impact indicators (global warming potential, embodied energy and total impact). Altogether, 127 mixtures are analyzed, such as mortars, concretes, masonry and paving blocks. The impacts of OSPW drying and logistics are presented, as well as the impacts of the process (burning) to produce the heat-treated waste (HTOSPW). The results indicate that OSPW is a good alternative to reduce environmental impacts in the analyzed scenario (Espírito Santo (ES) state – Brazil), as a replacement for limestone filler, sand or stone dust. OSPW could be used as a cement partial replacement and presented satisfactory environmental results at high replacement levels (over 50%) in the production of self-compacting concrete, rendering and masonry mortars. The results also show that the artificial drying alternatives greatly increase the OSPW impact. Regarding the production of the mixtures, cement replacement was the approach most commonly used, causing a reduction in environmental impact indicators of 7.7 to 9.0% for each 10% of OSPW use.

Sealing efficiency of cement-based materials containing extruded cementitious capsules

The intensive use of cement-based building materials is a growing concern in terms of environmental impact, since they significantly contribute to the global anthropogenic CO2 emissions. The development of self-sealing cementitious materials could be a possible approach to improve the structural durability and thus reduce overall cost and environmental impact. In the present work, the efficiency of a self-sealing system using extruded cementitious capsules was experimentally investigated, and different healing agents were tested (specifically, a water-repellent agent, a polyurethane precursor and a solution of silica gel immobilized ureolytic bacteria). The self-sealing efficiency was evaluated in terms of capability to autonomously seal localized cracks induced in a controlled way. An active crack width control technique was adopted during the cracking procedure, in order to reduce the variation of the crack width within a series of specimens. Water permeability and capillary water absorption tests were performed to quantify the crack sealing ability, along with qualitative visual analysis of the crack faces. Positive results were achieved when using the water-repellent agent in water absorption tests, the bacterial agent in water-flow tests and the polyurethane precursor in both cases. This suggests that the proposed self-sealing system is sufficiently versatile to be used with different healing agents and that it can be effective in prolonging the material functionality by selecting the most appropriate agent for the real operating conditions.

Analisis Risiko Potensi Bahaya dan Pengendaliannya Dengan Metode HIRADC pada PT. IGASAR Kota Padang Sumatera Barat

<p>PT IGASAR was one of the companies affiliated with PT Semen Padang with business activities in the fields of engineering, cement distribution, transportation, heavy equipment rental, cement-based building materials industry, manufacturing, general contractor, and developer. Some work accidents were still found in activities at this company. It was essential to making hazard identification, risk assessment, and determined the type of control in some areas. There are work accidents in PT IGASAR in as many as five cases in 2017 - 2018. One way was to use the Hazard Identification Risk Assessment Determine Control (HIRADC) Method. A risk analysis was done by looking at the opportunities and the severity of the hazards. Based on the results of the risk analysis, it was found that activities that were low risk, very high risk was absent while the medium risk was 100%. The risk control measures include the provision of personal protective equipment, the rule of safety signs, equipment maintenance, and the creation of road area boundaries.</p>

Ultrasonic Evaluation of Cement-Based Building Materials Modified Using Marble Powder Sourced from Industrial Wastes

This paper presents an experimental study on the assessment of the cement-based materials properties made with marble powder (MP) at different replacement ratios (0%, 5%, 10%, and 15%) of cement by using the ultrasonic pulse velocity (UPV) test. The used MP has a Blaine fineness similar to that of Portland cement. The physical and the chemical characteristics of Portland cement and MP were determined. To determine the UPV values, cubic specimens (50 × 50 × 50 mm3) of cement paste and mortar were prepared and cured either in air at a temperature equal to 22 ± 2 °C and relative humidity equal to 20 ± 1%, or in water at a temperature equal to 20 ± 1 °C. The experimental tests including the UPV, the compressive strength (fcd), and the apparent density (ϒad) were conducted at 3, 7, 28, and 65 days, the relationship between each of these parameters were presented. Additionally, economic performance of cement and waste MP used in this study was performed. The results show that the use of MP as partial replacement of cement causes a decrease in the compressive strength and apparent density in both curing conditions. In addition, the results show a good relationship between the destructive test and non-destructive test adopted by UPV.

Photocatalytic BiOX Mortars under Visible Light Irradiation: Compatibility, NOx Efficiency and Nitrate Selectivity

The use of new photocatalysts active under visible light in cement-based building materials represents one interesting alternative to improve the air quality in the urban areas. This work undertakes the feasibility of using BiOX (X = Cl and I) as an addition on mortars for visible-light-driven NOx removal. The interaction between BiOX photocatalysts and cement matrix, and the influence of their addition on the inherent properties of the cement-based materials was studied. The NO removal by the samples ranking as follows BiOCl-cem > BiOI-cem > TiO2-cem. The higher efficiency under visible light of BiOCl-cem might be ascribed to the presence of oxygen vacancies together with a strong oxidation potential. BiOI-cem suffers a phase transformation of BiOI in alkaline media to an I-deficient bismuth oxide compound with poor visible light absorbance capability. However, BiOI-cem showed considerably higher nitrate selectivity that resulted in the highest NOx global removal efficiency. These results can make its use more environmentally sustainable than TiO2 and BiOCl cement composites.

Synergetic effect of waste tire rubber and mil scale on electromagnetic wave attenuation properties of new generation mortar

In this study, the behaviors of cement based building materials containing a certain amount of crumb rubbers (CR) and mill scales as additives were explored. For this purpose, five different CR content by volume of the natural fine aggregate mortars and different mill scale (MS) doped rubberized mortars were prepared. The CR and MS used in the study were obtained from waste tires and rolling mill facility which are desirable due to economic and environmental reasons. EM behaviors of the samples were explored in the frequency range of 3–12GHz for the first time in the related literature. Flexural and compressive strength tests are then carried out. The crystallinity and morphology of the mortars were also investigated with X-ray Diffraction (XRD) and Scanning Electron Microscope (SEM). The increment of rubber content in the mortar reduced the reflection characteristic due to lower reverse polarizability of the structure with incident wave, related with the dielectric properties of rubber and decreased the reflection response of the mortar due to reduced polarization of the samples with increased dielectricity for incident wave. The dielectric constants of mortar including mill scale has higher values due to better polarizability of the small conductive parts in mill scale. The existence of conductive parts increases the electron mobility and polarizability of the structure. Besides, the higher ratio of rubber with the same mill scale percentage (15%) in mortar also slightly enhanced the dielectricity of the samples. The higher dielectric constant with respect to the free space gives opportunities to be used in shielding devices. The replacing crumb rubber with fine aggregate resulted in a decrease in both compressive and flexural strength.

Imobilizacija teških metalnih jona Zn2+, Ni2+, Pb2+ i Cu2+ u strukturi materijala na bazi cementa

Natural zeolite and bentonite were utilized as mineral additives in the mix-design of environmentally safe cement-based building materials. The adsorptive abilities of these two clayey raw materials, i.e. their affinity to immobilize heavy metal ions Zn2+, Ni2+, Pb2+ and Cu2+ were investigated. Singleand multi-solutions of Zn2+, Ni2+, Pb2+ and Cu2+ were prepared for the experiment. The obtained results were submitted to analysis via pseudo-first and pseudo-second order kinetic models. Langmuir and Freundlich isotherms were analyzed. Bentonite exhibited better adsorption affinity than zeolite towards all four investigated cations. As a proof, a leaching test was conducted on seven different cement binders with different mineral additives (fly ash, zeolite, bentonite). The leachates obtained on the samples of cement with addition of fly ash and clay (either zeolite or bentonite) contained lower concentrations of Zn2+, Ni2+, Pb2+ and Cu2+ ions than leachates obtained on the samples of cement binder with fly ash solely as a result of adsorption and hydration mechanisms that immobilized heavy metals within cementitious composites.

Increasing efficiency of carbon dioxide sequestration through high temperature carbonation of cement-based materials

Abstract The increasing global carbon dioxide concentration has received significant public attention in recent decades, with various sequestration methods being proposed by researchers all around the world. The enormous amount of generated cement-based building materials, such as waste concrete aggregate, particularly exhibits a great carbon dioxide fix potential through the carbonation process. However, the slow reaction speed in a normal environment prohibits its further application. On the other hand, exhaust carbon dioxide emitted from a cement factory is usually in a broad temperature range. Therefore, high temperature carbonation is proposed to accelerate the carbon dioxide sequestration speed in this study. The carbonation performance and carbon dioxide uptake rate of cement paste blocks and powder were evaluated in a broad temperature range (20 °C–300 °C), demonstrating that carbonation speed was greatly affected by temperature, with optimum carbonation temperature appearing at around 100 °C, at which cement paste samples could achieve the fastest carbonation speed at a rate of 16.4%/h in the first 1 h compare to 2.4%/h at normal temperature. In addition, the inner liquid water content of samples was another great influential factor which is related closely to the calcium carbonate generation rate from different hydrate substances, and adding liquid water into samples at appropriate time intervals could enhance carbonation reaction effectively, with the maximum improvement of 34.1%. Consequently, it was found that an improvement could be achieved at 100 °C in comparison with normal temperature, with a further increase of 721% being attained by adding liquid water every 20 min to 2 mm thickness cement paste blocks.

Reinforcing Mechanism of Graphene and Graphene Oxide Sheets on Cement-Based Materials

AbstractGraphene and graphene oxide (GO) sheets have great potential to improve the properties of traditional cement-based building materials. This research studied the effects of graphene and GO s...

Effect of glass addition on the properties of cements (CEMI)

The purpose of this study is to recover mineral residues as an additive in cement-based building materials. It is part of a sustainable development approach. The use of recovered and recyclable industrial residues in partial replacement of Portland cement reduces greenhouse gas (GHG) emissions and results in the manufacture of cement with a lower environmental impact.
 Using various experimental techniques, particular attention is paid to the behaviour of the glass powder finely crushed and chemically activated associated with Portland cement. This study confirms the improvement in the physicochemical and mechanical properties of cements with the addition of glass powder, which augurs well for its use as a cement additive.

Effect of glass addition on the properties of cements (CEMI)

The purpose of this study is to recover mineral residues as an additive in cement-based building materials. It is part of a sustainable development approach. The use of recovered and recyclable industrial residues in partial replacement of Portland cement reduces greenhouse gas (GHG) emissions and results in the manufacture of cement with a lower environmental impact. Using various experimental techniques, particular attention is paid to the behaviour of the glass powder finely crushed and chemically activated associated with Portland cement. This study confirms the improvement in the physicochemical and mechanical properties of cements with the addition of glass powder, which augurs well for its use as a cement additive.