Partial Replacement Of Portland Cement Research Articles

Early-age effect of corn cob ash as a partial replacement for Portland cement in concrete

One of the effects of supplementary cementitious materials (SCMs) in concrete is the dilution effect which is as a result of partially replacing Portland cement with SCMs. The dilution effect of corn cob ash (CCA) with respect to strength gain and transport properties of concrete is the focus of this study. 100 mm concrete cubes were prepared with corn cob ash partially replacing Portland cement at 15% and 30% using w/b ratio of 0.4 and 0.6. The effect of CCA replacement level on the compressive strength development between 3 and 28 days, and transport properties at 28 days of curing was done. This was compared to the effect of fly ash at the same replacement level and 100% Portland cement content. The results showed that compressive strength decreases with increasing ash content and increases with increasing curing age. The dilution effect of CCA was more pronounced at the two replacement levels than fly ash with a marginal gain or strength loss compared to w/c ratio corresponding to each w/b ratio. The oxygen permeability index obtained for CCA concrete were lower compared to that of fly ash concrete at the same replacement levels and PC concrete at the same w/b ratio. Also, the water sorptivity index and chloride conductivity index for CCA concrete were higher than that of fly ash and PC concrete at the same w/b ratio.

Utilization of Low-Alkalinity Cementitious Materials in Cemented Paste Backfill of Gold Mine Tailings

The purpose of this paper was to explore the possibility of using low-alkalinity cementitious materials as binders, in which ground blast furnace slag and fly ash acted as a partial replacement of ordinary Portland cement, and CaSO4, Na2SO4, and CaO were used as a sulfate activator and alkali-activated additives, to solidify gold mine tailings for preparation of a green, inexpensive cemented paste backfill (CPB). For this target, the effects of cement/ tailings ratio, superplasticizer dosage, solid content, tailings fineness on the mechanical properties of the CPB were investigated. Additionally, the hydration mechanism of the CPB was analyzed based on X-ray diffraction and scanning electron microscopy results. The results showed that the fluidity of the CPB slurry could be improved by adding polycarboxylic acid superplasticizer. The unconfined compressive strength (UCS) of the CPB specimens was increased with the increase of cement/tailings ratio and solid content. Under the same experimental conditions, the 28 d UCS of the CPB specimens was 3.8~4.9 times higher than that of ordinary Portland cement. The softening coefficient of the CPB specimens was increased with the increasing cement/tailings ratio, ranging from 0.83 to 0.92. The shrinkage rate of the CPB specimens was decreased from 0.70% to 0.54% with the increase of cement/tailings ratio from 1:12 to 1:4. The UCS of the full tailings CPB was the highest, followed by the fine tailings CPB specimens, and the UCS of the coarse tailings CPB specimens was the lowest. The low-alkalinity binder was proved to be a promising material to improve the engineering performances of the CPB. The optimal mixing ratio is 1:6 cement/tailings ratio, 0.15 wt% superplasticizer dosage, and 70 wt% solid content. Prepared by this mixing ratio, the UCS values of the CPB after 3, 7, and 28 d curing ages reached 1.85, 5.87, and 9.16 MPa, respectively, which were suitable as CPB for the Zhaoyuan gold mine in terms of strength requirements.

Effect of high temperature on the strength of mortar containing glass as a supplementary cementitious material: An experimental study

The present scenario of the construction sector has changed rapidly due to economic growth and urbanization. The consumption of ordinary Portland cement has immensely increased worldwide due to huge cement concrete demand. However, the significant consumption of cement has drastically enhanced environmental pollution and led to prime CO2 emitter and contributing to global warming. It is observed globally that cement production is solely contributing to 58% of the overall man-made CO2 emissions. Accordingly, an appropriate solution to the problem is using different types of waste in concrete as cementitious material to reduce CO2 emissions, which is a fruitful approach to control global warming and promote sustainable construction. It is further noticed that the rapid growing waste like glass and its disposal in landfills is not an environmentally friendly solution in regards to the non-biodegradable nature of glass. Hence, this experimental study works on exploring the solution to the above mentioned problem and projects the performance of glass powders (GP) as a partial replacement for ordinary Portland cement under elevated temperatures.The results reported in this study reveal that the strength retained by the cement after heating is a very vital parameter when introducing new cementitious material in cement. For the purpose, several mixes were prepared in which glass powder is utilized from 10%, 20% and 30% of cement replacement. The glass mortar cubes were tested in compression at various temperatures ranges like room temperature, 200, 400, 600 and 800 °C. Results show sample with 10% GP retained more compressive strength and showed sound performance than the normal sample under elevated temperature. The result shows two distinct temperature series regarding the incorporation of glass powder on the strength of mortars. The mortar mix with 20% GP showed a noble performance by retaining the decent residual strength after heating, and the average strength loss of the reference sample was observed at 5.2% more than the glass mortar sample. After temperatures range 400 °C, the rapid strength loss was encountered, which may be due to the dehydration of CH.

Analysis of the current scenario of Compressed Earth Block (CEB) production

The main objective of this study is to identify the parameters that influence the quality of the production of compressed earth blocks (CEB). Thus, an analysis of the performance of the materials that make up the final product was carried out, such as the binders that act as chemical stabilizers and the different types of soils, also the mechanical resistance and durability tests and finally the technical standards for its manufacturing. For this aim, a literature review was carried out in three electronic databases, Scopus, Web of Science and Scielo. The results showed environmental concerns with the use of Portland cement for stabilization, therefore, 18% of the studies used agricultural residues and 25% used mineral by-products, for partial or total replacement of Portland cement. Soils with plasticity indexes between 15% and 30% have a stabilization success rate of 69%, while soils with plasticity index less than 15% have a stabilization greater than 93%, which can be increased to 100% if the soil have a percentage of clay and silt between 21 and 35%. On the other hand, a plasticity index above 30% negatively affects stabilization. The compaction energy applied in the manufacture of CEB is an important parameter, as it influences the density, thermal conductivity and mechanical strength. Among the sustainable construction techniques, CEB is a great option, as it can be done locally and with ease of construction.

Reducing detrimental sulfate-based phase formation in concrete exposed to sodium chloride using supplementary cementitious materials

The sodium chloride (NaCl) can chemically interact with the monosulfate (AFm) within the concrete matrix, leading to a detrimental sulfate-based phase formation during thermal cycling. This paper studies the potential of reducing the sulfate-based phase in the cementitious pastes made using different types of supplementary cementitious materials (SCMs) used as a partial replacement of ordinary portland cement (OPC). A low-temperature differential scanning calorimetry was used to quantify the amount of the sulfate-based phase. The results indicated that the addition of SCMs as a partial replacement of OPC revealed different effects on forming the sulfate-based phase through pozzolanic activities and/or dilution effects. The addition of slag or class F fly ash can lower the formation of the sulfate-based phase through the dilution effect, while the addition of silica fume can substantially lower the formation of the sulfate-based phase by both dilution and pozzolanic activities. The use of class C fly ash, however, showed negative effects through increasing the formation of the sulfate-based phase. Thermodynamic modeling was used to predict the phase equilibrium of hydrated cementitious systems. Results from thermodynamic predictions were in agreement with the experimental results, indicating that the formation of the sulfate-based phase was associated with the amount of AFm present in the cementitious systems.

A study on workability and mechanical properties of eco-sustainable self-compacting concrete incorporating PCB waste and fly ash

Electronic wastes containing metallic and nonmetallic hazardous materials, if left untreated, are severely harmful to the environment, social, ecosystem, and human well-being. In this study, the effects of substituting recycled electronic waste, i.e., printed circuit board (PCB) dust, and fly ash (FA) concurrently as a partial replacement of ordinary Portland cement (OPC) in self-compacting concrete (SCC) was investigated to explore a novel electronic waste recycling method and new material of construction. The decisive parameters of e-waste mixed cement SCC are workability characteristics and hardened properties. According to the design of experiments, the ratio of PCB dust waste in OPC were 0%, 5%, 10%, 15%, 20%, and 30% whilst the ratio of FA in OPC were 10%, 20%, and 30% by volume. Workability characteristics were verified by means of rheological behaviors, i.e., slump diameter, T500 flow time, test V-funnel test, J-Ring test and L-box test. Compressive strength, split tensile strength, flexural strength, and ultrasonic pulse velocity up to 180 days were determined for its hardened properties. According to the result, recycled PCB dust with FA can be used as cement replacement for SCC. Combining use of recycled PCB dust and FA as filler and pozzolanic synergistically yielded satisfactory results, e.g., greater than 60 MPa of compressive strength at 28 days for 5% PCB dust and 10% FA. In addition, compressive strength at 180 days of highest cement replacement level at 60% was greater than 40 MPa. Eventually, there are opportunities to use combined PCB dust and FA as cement replacement in SCC which yields cost saving and eco-sustainable SCC products that are economically and environmentally beneficial for the construction industry.

Synthesis of Cement Composites Utilizing Ceramic Waste as a Partial Replacement for Portland Cement: Literature Review

Abstract The unchecked emissions of hazardous gases emanating from the cement industry have effectuated much research geared toward utilizing solid waste materials as cement replacements. This stud...

Characterizing fiber reinforced concrete incorporating zeolite and metakaolin as natural pozzolans

Supplementary cementitious materials (SCMs), including industrial by-products or natural pozzolans are widely used as a partial replacement of ordinary Portland cement (OPC) in eco-friendly concrete, to reduce the carbon footprint and enhance mechanical and durability properties. Although many experiments have been conducted to study the effect of SCMs in concrete, the research on the effect of natural pozzolans on fiber reinforced concrete (FRC) is limited. This study investigates the effect of different amounts of metakaolin and zeolite pozzolans on the mechanical properties and durability of concrete containing polypropylene fibers. A total of 99 specimens were made in 11 experimental groups and the parameters of compressive strength, tensile strength, water absorption, porosity and density of concrete specimens were evaluated. In addition, concrete specimens were tested for ultrasonic pulse velocity (UPV) and atomic force microscopy (AFM) to further study the effect of natural pozzolans on the microstructure of concrete. The performance of FRC with natural pozzolans was compared to that of reference concrete and fiber reinforced concrete without SCMs. The results indicated that the polypropylene (PP) fibers were more effective in enhancing mechanical properties of concrete in the zeolite mixtures, so that the compressive strength and tensile strength compared to reference concrete increased by 44 and 22%, respectively, while the water absorption and porosity decreased by 48 and 45%, respectively. This is attributed to the higher viscosity of the zeolite-mixtures that allowed for a better dispersion of fibers in the mixture as well as the improved bond strength between fibers and paste due to the high pozzolanic activity of zeolite. The AFM analysis, UPV, density, and permeable voids test results revealed that the FRC mixtures incorporating natural zeolite had the most dense microstructure and the least porosity and defects among all examined FRC mixtures even compared to the mixtures that incorporated metakaolin with the same cement replacement level.

Effects of a Natural Mordenite as Pozzolan Material in the Evolution of Mortar Settings.

This paper shows the results of a study focused on the evolution and properties of mortars made with a mixture of portland cement (PC) and natural mordenite (Mor). To begin, samples of mordenite, cement and sand were studied with X-ray diffraction (XRD), X-ray fluorescence (XRF) and granulometric analysis (GA). Next, mortars with a ratio of 75% PC and 25% mordenite were prepared to determine their initial and final setting times, consistency and density. Continuing, the density, weight and compressive strength of the specimens were determined at 2, 7, 28, 90 and 365 days. Finally, the specimens were studied using SEM, XRD and XRF. The results of the study of the mordenite sample showed a complex constitution where the major mineral component is mordenite, and to a lesser degree smectite (montmorillonite), halloysite, illite, mica, quartz, plagioclase and feldspar, in addition to altered volcanic glass. Tests with fresh cement/mordenite mortar (CMM) showed an initial setting time of 320 min and a final setting time of 420 min, much longer than the 212–310 min of portland cement mortar (PCM). It was established that the consistency of the cement/mordenite mortar (CMM) was greater than that of the PCM. The results of the density study showed that the CMM has a lower density than the PCM. On the other hand, the density of cement/mordenite specimens (CMS) was lower than that of portland cement specimens (PCS). The CMS compressive strength studies showed a significant increase from 18.2 MPa, at 2 days, to 72 MPa, at 365 days, with better strength than PCS at 28 and 365 days, respectively. XRD, XRF and SEM studies conducted on CMS showed a good development of primary and secondary tobermorite, the latter formed at the expense of portlandite; also, ettringite developed normally. This work proves that the partial replacement of PC by mordenite does not have a negative effect on the increase in the mechanical strength of CMS. It indicates that the presence of mordenite inhibits the spontaneous hydration of C3A and controls the anomalous formation of ettringite (Ett). All this, together with the mechanical strength reported, indicates that mordenite has a deep and positive influence on the evolution of the mortar setting and is an efficient pozzolan, meaning it can be used in the manufacture of mortars and highly resistant pozzolanic cement, with low hydration heat, low density, stability in extremely aggressive places and a low impact on the environment.

Using Partial Substitution of Portland Cement with Silica Fume and CKD to Determine the Ultrasonic Pulse Velocity of Cement Mortar

Portland cement considered one of the most pollutant material used in the construction industry, which is responsible for several harmful emissions like a greenhouse gas. This causes particular environmental interest in the production of concrete and its components. for that, it becomes necessary to find an alternative material for ordinary Portland cement with good environmental impact as well as good construction properties. The aim of this paper is to investigate the effects of partial replacement of ordinary Portland cement by industrial by-products substances in the cement mortar. The industrial by-products used in the present research is silica fume and cement kiln dust (CKD). Various mortar specimens are prepared by replacing the in different proportion of 20%, 40, and 60% of a mixture from CKD and SF. the testing of samples were conducted after curing the specimens for 7-days and 28-days. The strength of specimens was tested by ultrasonic pulse velocity (UPV) test. The results show that the optimum percentage of replacement Portland cement by silica fume and CKD was involved from 20% to 28%. The increment in the percentage of CKD& silica fume till the optimum percentage shows good enhancement in the pulse velocity of samples, while the additional quantities of these by-products start to reduce the pulse velocity of samples.

Porosity Evaluation of Concrete Containing Supplementary Cementitious Materials for Durability Assessment through Volume of Permeable Voids and Water Immersion Conditions

Concrete containing supplementary cementitious materials (SCMs) as partial replacement of ordinary Portland cement is regarded as green and durable concrete, with several advantages such as improved strength gain mechanism, resistance to degradation and extended service life of structure. Water absorption or porosity of concrete is directly related to the durability of concrete. In this present study, five concrete mixes involving three different SCMs are investigated for water absorption and rapid chloride penetration rating. A comparison between porosity values obtained using four standard testing methods, i.e., BS 1881-122, RILEM CPC 11.1, RILEM CPC 11.3, and ASTM C642 are presented for three different concrete mixes containing varied compositions and proportions of two SCMs. The testing method by RILEM CPC 11.3 includes distinctive sample preparation and is regarded as a stringent method to represent the degree of concrete porosity. Two additional concrete mixes with three SCMs are further investigated for their water absorption and immersion following the testing method by RILEM CPC 11.3. The impact of SCMs on concrete porosity is discussed. A linear correlation between porosity and rapid chloride penetration (RCP) ratings obtained as per ASTM C1202-19 on specimens of all investigated concrete mixes is proposed as a rapid approach to assess chloride penetration of concrete specimens containing SCMs.

Physical, Mechanical and Durability Properties of Ecofriendly Ternary Concrete Made with Sugar Cane Bagasse Ash and Silica Fume

In the present investigation, the physical, mechanical and durability properties of six concrete mixtures were evaluated, one of conventional concrete (CC) with 100% Portland cement (PC) and five mixtures of Ecofriendly Ternary Concrete (ETC) made with partial replacement of Portland Cement by combinations of sugar cane bagasse ash (SCBA) and silica fume (SF) at percentages of 10, 20, 30, 40 and 50%. The physical properties of slump, temperature, and unit weight were determined, as well as compressive strength, rebound number, and electrical resistivity as a durability parameter. All tests were carried out according to the ASTM and ONNCCE standards. The obtained results show that the physical properties of ETC concretes are very similar to those of conventional concrete, complying with the corresponding regulations. Compressive strength results of all ETC mixtures showed favorable performances, increasing with aging, presenting values similar to CC at 90 days and greater values at 180 days in the ETC-20 and ETC-30 mixtures. Electrical resistivity results indicated that the five ETC mixtures performed better than conventional concrete throughout the entire monitoring period, increasing in durability almost proportionally to the percentage of substitution of Portland cement by the SCBA–SF combination; the ETC mixture made with 40% replacement had the highest resistivity value, which represents the longest durability. The present electrical resistivity indicates that the durability of the five ETC concretes was greater than conventional concrete. The results show that it is feasible to use ETC, because it meets the standards of quality, mechanical resistance and durability, and offers a very significant and beneficial contribution to the environment due to the use of agro-industrial and industrial waste as partial substitutes up to 50% of CPC, which contributes to reduction in CO2 emissions due to the production of Portland cement, responsible for 8% of total emissions worldwide.

Influence of Additives on Flexural Strength of Roller Compacted Concrete

Roller compacted concrete is considered as a sustainable solution. In the present investigation, three types of additives namely (fly ash, fumed silica, and hydrated lime) are implemented as partial replacement of Portland cement for preparation of roller compacted concrete slab samples using dense and gap aggregate gradation. The slab samples were prepared at optimum cement requirement of 12 % and at (2 and 4) % cement below and above the optimum. Beam specimens of (38 x 10 x 8) Cm were extracted from the slab samples using diamond saw. The specimens were subjected to flexural strength determination using two testing modes, the three and the four points loading. It was noticed that the flexural strength under four-points loading mode is lower by a range of (0.787 to 0.732) folds than that under three-points loading mode for dense and gap graded mixtures respectively. It was concluded that the flexural strength increases by (96.2, 84, and 17.2) % and (109, 86, and 9.3) % after replacement of (10, 12, and 15) % of cement by hydrated lime while it declines by (50, 64.6, and 77) % and (0.1, 30.8, and 63.5) % after replacement of (5, 7, and 10) % of cement by fumed silica for dense and gap graded aggregates respectively. The flexural strength of dense graded mixtures increases by 63 % at 20 % replacement by fly ash, however, it increases by (99.7, 53.8, and 1.0) % after replacement of (10, 12, and 15) % of cement by fly ash for gap graded aggregates respectively.

Performance optimization of ground rubberized green concrete with metakaolin

The disposal of waste vehicle tires is an environmental and health problem, as their recycling is very difficult. One of the effective ways of recycling is using these tires as partial replacement of Portland cement in construction industry. In this study, a systematic experimental study (by making 810 laboratory samples) is performed on concrete made with finely ground rubber (GR) and metakaolin (MK) as partial replacements of cement to investigate the compressive strength, splitting tensile strength, flexural strength, water absorption, and dry unit weight. The main goal of this study is to achieve the optimal proportions of concrete incorporating GR and MK by maximizing mechanical strengths while minimizing the water absorption (WA) of concrete. To do so, 7 concrete mixtures containing GR are produced with 3 different cement contents: 350, 400, and 450 kg/m3 in conjunction with 2 different water-cement ratios: 0.45 and 0.50. Also, 1 concrete mix is used to optimize the concrete with hybrid blends of GR and MK by employing the response surface methodology (RSM). GR and MK are applied as partial replacements of Portland cement in ranges of 0–30 vol% and 0–20 vol%, respectively. The results show that the use of GR and MK in concrete has a significant effect on its mechanical and durability properties and, thus, reduces the cement consumption which can contribute to decreasing the negative impacts of cement production on the environment. According to the optimization results, 4.2% and 19.5 vol% replacements of cement with GR and MK, respectively, can be considered as the optimum mixture compositions of hybrid concrete to maximize compressive and splitting tensile strengths by about 1–4% and 6–8%, respectively, while minimizing WA by about 48%. Depending on the flexural strength results, the amounts are changed into 1.8% and 14.7% while the flexural strength increases by about 11%.

Crack properties, toughness and absorption evaluation of FRCC incorporating reclaimed asphalt pavement and crumb rubber as aggregates

The development and application of fibre-reinforced cementitious composites (FRCC) have evolved significantly over the last decade. However, there is a need to find innovative ways to improve the sustainability of composites. The production and transportation of the major binder (i.e. Portland cement) and aggregates used for FRCC consumes high energy and natural resources. Therefore, finding ways to incorporate recycled materials to replace these conventional components can be used to improve the sustainability of the FRCC. Also, the special micro silica sand used to produce certain types of FRCC is a major concern due to its limited availability and higher cost. On the other hand, there exist various waste materials that can be incorporated into FRCC as a replacement of either the binder or aggregate. Hence this current paper aims to investigate the performance of FRCC made with high volume fly ash as partial replacement of Portland cement, and reclaimed asphalt pavement/crumb rubber as replacement of the natural aggregates. The performance of the FRCC incorporating these recycled materials was evaluated in terms of its crack properties, toughness and sorption. Results from this study showed that the use of recycled crumb rubber is beneficial in terms of crack properties and lower sorption. The sorption of FRCC incorporating crumb rubber as the only aggregate was reduced by 31.8%. However, FRCC made with reclaimed asphalt pavement exhibited higher sorption and lower toughness.

Strength Assessment of Concrete using Rice Husk Ash, Polyvinyl Alcohol Fiber and Recycled Concrete Aggregate: A Critical Review

In this review study, the effect of three different materials such as rice husk ash, recycled concrete aggregate and Polyvinyl Alcohol fibre was reviewed in detail. Several past studies related to these material usage in strength enhancement of concrete was studied in detail. Rice husk ash is the ash which is mainly derived after burning the waste derived from the rice industry after the processing of rice. Recycled concrete aggregate is mainly the aggregate derived from the constructional waste. Polyvinyl Alcohol fibre is a special type of high strength fibre that is mainly used to improve the flexural strength and internal bonding of the concrete. Numerous studies were discussed in detail and depending upon the studies certain conclusion are drawn which are discussed further. Several studies related to the usage of rice husk ash conclude that the most optimum usage percentage of rice husk ash as partial replacement of ordinary Portland cement was at 10 percent usage. After 10 percent usage strength tends to decline. Results related o usage as partial replacement of natural fine aggregate that is sand showed that it can be used as partial replacement of natural coarse aggregate up to 20 percent and beyond that usage the strength was declining. The studies related to the usage of recycled concrete aggregate conclude that the most optimum percentage of usage of recycled concrete aggregate as partial replacement of natural coarse aggregate was 50 percent replacement and beyond this percentage the strength starts declining so therefore should not be used beyond that limit. Studies related to the usage of Polyvinyl Alcohol fibre revealed that the most optimum percentage of Polyvinyl Alcohol fibre was 1.5 percent and beyond this percentage both the compressive strength of concrete and flexural strength of concrete was declining. Test results concluded that Polyvinyl Alcohol fibre should be used up to 1.5 percent only.

Evaluation of the mechanical and durability properties of eco-efficient concretes produced with porcelain polishing and scheelite wastes

The construction industry uses large-scale natural resources to production of concrete among which cement and aggregates are fundamental components. This process causes environmental impacts that are not aligned with sustainable propositions and perspectives. Likewise ceramic and mining industries generate various wastes disposed of inappropriately which can be harmful to environmental systems. Given these facts the present study aims to understand better the physical mechanical and durability of eco-efficient concrete produced with partial and hybrid substitutions of cement and sand by porcelain polishing residue (PPW) and scheelite residue (SW) respectively. For this an experimental campaign was developed divided into two stages. The first phase consisted of performing tests (consistency water absorption and porosity by immersion and compressive strength) in concretes with fixed fine aggregate contents (mixture of 81% and 19% of SW and sand respectively) and with partial replacement of Portland cement by 0 5 10 15 20 25 and 30% of PPW aiming to select the mixture with better physical and mechanical performance. Finally the second experimental phase consisted of evaluating the evolution of compressive strength and durability (capillary water absorption and chloride penetration) properties of the selected eco-efficient concrete. A microstructural analysis using XRD was also conducted to identify the main phases present in the concretes with wastes. The results showed that 15% is the optimum content to replace cement with PPW. A decrease in the consistency compressive strength water absorption and porosity of the concretes with this waste compared to the reference mixture was also observed 28 days. However at 90 days the mechanical behavior of the concretes was improved due to the filling effect and the pozzolanic activity of PPW. The durability properties indicated less pore connectivity and resistance to chloride migration equivalent or slightly higher than the reference concrete.

Sustainable design of concrete using industrial additives and wastes

AbstractConcrete is the most widely used construction material in the world. Over ten billion tons of concrete are being produced each year resulting in exhaustion of natural materials and an enormous carbon footprint. One of the primary goals of concrete technology today is to reduce the use of Portland cement and natural fine aggregates by partially replacing them with various waste materials and by-products of industrial processes. The paper summarizes the results of a study where the partial replacement of river sand and Portland cement was successfully applied using steel slag aggregate, silica fume and glass waste.

Quaternary blended cement mortars containing wood ash, glass and slag powders

AbstractA quaternary supplementary cementitious materials as partial replacement of ordinary Portland cement decreases CO2 emission. This paper has investigated the properties of mortars made from different quaternary blends of wood ash, steel slag powder and glass powder with ordinary Portland cement at different replacement levels of 0, 24, 25, and 30% by weight of the binder. The blended mortar mixtures tested for flow, compressive strength and density. The results showed that the flow of mortars is decreased with the combined use of steel slag powder, glass powder, and wood ash compared with control mix. Compressive strength reduced with the combination of steel slag powder, glass powder and wood ash but this reduction effects is acceptable especially at 24% replacement contain super-plasticizer compared with the ecological benefit.

Optimizing laterite cement blocks in the construction of masonry using quarry dust

Laterite soils mixed with Portland cement are used worldwide in making blocks. However, due to the environmental effects associated with the high usage of cement, quarry dust proved to be a good substitute for partial replacement of Portland cement. This study investigates the optimisation of laterite-cement blocks as walling materials using quarry dust. Physical properties of experimental soil were determined, and other tests such as compressive strength, density, water absorption were conducted on sample blocks under curing periods of 7, 14, 21, and 28 days. The blocks comprised of different percentages of laterite soil (76%, 81%, 85% and 87%), quarry dust (9% and 10% by weight of the soil) and ordinary Portland cement (3%, 5%, 10% and 15% by weight of the soil. The results showed that cement content of 10% and 9% quarry dust was suitable for the block at any curing period above 7 days. The compressive strength increased with an increase in the curing period no matter the percentage of the materials used in the study. The study recommends the usage of quarry dust in cement laterite blocks. However, further investigation on other vital parameters like abrasion resistance test could be conducted.