Piyush Chaunsali

Indian Institute of Technology Madras | IIT Madras · Department of Civil Engineering

Calcium sulfoaluminate (CSA) cements have lower carbon footprint than that of portland cement, which makes them a suitable alternative as a sustainable cementitious binder. Early-age expansion of CSA cements can be exploited to induce compressive stress in restrained concrete which can later counteract tensile stress developed during drying shrinka...

The present study aims at examining the physico-chemical factors influencing the expansion characteristics of OPC-CSA blend in the presence of mineral admixtures. Three different admixtures: Class 'F' fly ash ('F'FA), Class 'C' fly ash ('C'FA) and silica fume (SF) were used as 15%, 15% and 5% replacement of total cementitious binder. Longitudinal e...

Characterization of a nontraditional binding material containing cement kiln dust (CKD) and ground granulated blast furnace slag (GGBFS) is discussed in this paper. Significant compressive strength was obtained for a CKD–GGBFS blend with 70% CKD and 30% GGBFS at a water-to-binder ratio of 0.40 after 2 days of curing at elevated temperature. Similar...

This report discusses the application of expansive cements (Type K and Type G) and shrinkage-reducing admixtures (SRAs) in reducing the cracking due to drying shrinkage. The Type K expansive cement contained portland cement and calcium sulfoaluminate-based component whereas the Type G expansive system was made of portland cement and CaO-based compo...

Calcium sulfoaluminate (CSA) cements have been shown to have lower carbon footprint than that of Portland cement. In addition, the expansive nature of CSA-based cement can be utilized to enhance the resistance against shrinkage cracking by inducing compressive stress in concrete. The current paper reports the hydration and early-age volume changes...

Sewer structures are subjected to severe and rapid deterioration, mainly due to the biogenic acid attack. The bacteria such as Thiobacillus thiooxidans thrives in the pH range of 0.5-3 and converts H2S gas into sulfuric acid, causing the corrosion of sewer crown, leading to catastrophic failure of sewer and overlying structures. In addition to the...

Mixtures of powders of waste glass (WG), limestone (LS), Na2CO3 and CaO were used to formulate novel one-part in situ alkali-activated cement (WG-AAC). The in-situ interaction Na2CO3-CaO-H2O promoted the formation of CaCO3 and NaOH, which promoted the WG and LS dissolution and influenced the micro- and molecular features of the resulting cementitio...

Calcium sulfoaluminate belite (CSAB)-based cement exhibits useful properties such as low CO 2 footprint, high early-age strength and shrinkage compensating behavior. Our previous study examined the mechanism of carbonation in CSAB-based binder and reported a higher degree of carbonation in CSAB-based binder compared to Portland cement (PC) binder....

Calcium sulfoaluminate-belite (CSAB) cement is considered a viable and environmentally friendly alternative to Portland cement (PC). Ye’elimite or calcium sulfoaluminate, which is the primary phase of CSAB cement undergoes rapid hydration, leading to the formation of ettringite or monosulfate as the major hydration product. The reactivity of ye’eli...

Calcium sulfoaluminate belite (CSAB) cement has gained prominence as a viable environmentally friendly substitute for conventional portland cement (PC). The current study investigates the relative performance of expansive and nonexpansive CSAB cement-based concretes, and PC-based concretes when subjected to chloride-rich conditions. Multiple testin...

Calcium sulfoaluminate belite cement (CSAB) is an environment-friendly alternative to portland cement (PC). CSAB cement has been shown to have up to a 30% reduction in carbon dioxide emissions. Carbonation is one of the significant factors that can cause durability concerns in the reinforced concrete system. Carbonation of a cementitious system red...

When sulfate to ye’elimite ratio of Calcium sulfoaluminate (CSA) cement increases, it changes its application from rapid-strength cement to expansive (shrinkage compensating) cement. CSA cement is now getting attention because of its low carbon footprint. They are potential candidates for sewer structures where acid attack is the major durability t...

Acid attack is a common problem in sewers, agro-food industries, and underground structures. Calcium aluminate cement (CAC) has been found to be a superior binder for sewer application because of its hydrated alumina-dominant phase assemblage. Calcium sulfoaluminate (CSA) cement, having aluminium hydroxide as one of the hydrated phases, is a potent...

Calcium sulfoaluminate belite (CSAB) binder is an alternative low CO2 binder. CSAB cement has ye’elimite as the primaryclinker phase which hydrates to form monosulfate or ettringite as the main hydration product. The hydration and mechanicalcharacteristics of CSAB cement and PC-CSAB blended cement have been reported in several studies; however, stu...

Calcium sulfoaluminate (CSA) cements exhibit useful properties such as shrinkage compensation and rapid strength development. Acid resistance of CSA cement is majorly governed by its phase composition that varies significantly depending on the desired properties. In this study, acid resistance of CSA cement (i.e., non-expansive) and gypsum blended...

Biogenic acid attack of concrete is prevalent in sewers, posing a serious durability concern and financial burden. There are very limited number of field studies on durability of concrete under biogenic acid attack. Field study poses challenges with respect to the variation in climatic conditions and limited accessibility in sewers. Such a biogenic...

Agro-based biomass ashes can be chemically activated with Ca-Na based activators having low alkali concentration at ambient environmental conditions to produce sustainable binders. The utilisation of agro-based biomass ash in cementitious binders is restricted due to the presence of residual carbon, inconsistency in ash composition, and variability...

Agro-based biomass ash which is rich in reactive silica can be used to produce cementitious binders with reduced CO2 emissions. However, the compositional variability and the presence of unburnt carbon in the biomass ash affect its utilization potential. The standard reactivity assessment methods for supplementary cementitious materials (SCMs) have...

Ye’elimite is the primary reactive component in calcium sulfoaluminate-belite (CSAB) cement, and it has relatively lower raw material carbon footprint compared to Portland clinker phases. Ye’elimite produces ettringite when hydrated in the presence of calcium sulfate, and monosulfate in the absence of a sulfate source. The early age hydration prope...

Human colonization on Martian land is gaining significant attention in space exploration activities that demand in-situ resource utilization in the development of construction and building materials for human habitation. This research explores the utilization of Martian regolith simulant and sulfur to create extra-terrestrial concrete (ETC) with a...

Ordinary portland cement (OPC) manufacturing contributes to about 5–8% of the CO2 emissions globally and its consumption is expected to increase. Finding alternative to OPC is a global issue in the recent times. Calcium sulfoaluminate (CSA)-based binder is gaining attention due to the lower requirement of limestone and temperature requirement durin...

Calcium sulfoaluminate (CSA) cement is a low-CO 2 binder exhib-iting useful properties, such as shrinkage compensation and rapidhardening, which can be achieved by altering its phase composi -tion. In this paper, a hypothetical scenario of CSA cement manu-facturing at an existing Indian cement plant is investigated for theenvironmental consequences...

Cementitious materials are alkaline in nature. As a result, they are prone to neutralisation reaction by acids and possible deterioration. Among the existing binders, the acid resistance of calcium sulfoaluminate (CSA) cement is not well explored. Moreover, the phase composition of CSA cement varies significantly to reflect its expansive and non-ex...

Calcium sulfoaluminate (CSA) cement-based binders are low CO2 binders which exhibit rapid hardening or shrinkage compensating characteristics. Due to their unique properties, they have potential to be used in concrete elements exposed to acidic environment such as sewage system. In this paper, the performance of CSA-based binder in acidic environme...

Calcium sulfoaluminate belite (CSAB) cements are currently being promoted as alternative low CO2 cements. CSAB cements have ye'elimite as their primary phase. Ye'elimite hydrates rapidly to form ettringite which contributes towards high early-age strength. The hydration characteristics of ye'elimite are influenced by the presence of calcium sulfate...

Calcium sulfoaluminate (CSA)-based binders offer a promising way to enhance the sustainability and durability of concrete. Lower kiln temperature (i.e., 1250°C) requirement and lesser limestone demand for CSA cement’s manufacturing contribute to a significant reduction in its carbon footprint compared to Portland cement. Furthermore, the porous nat...

Portland cement manufacturing contributes to around 5-8% of the anthropogenic CO2 emissions globally. Consumption of portland cement in India and other emerging economies is expected to increase due to the steady growth of housing and infrastructure sectors. Finding alternatives to Portland cement is a global issue in recent times. To that end, cal...

Calcium sulfoaluminate (CSA) cements are widely being promoted as alternative low CO2 binders. CSA cements can also be expansive and designed to be shrinkage-compensating. The main phase of CSA cement is ye'elimite, which hydrates in the presence of calcium sulfate to form ettringite as the main hydration product. The availability of calcium sulfat...

Expansive characteristics of calcium sulfoaluminate-belite (CSAB) cement can be harnessed for making shrinkage-compensating concrete. The level of expansion is dependent on several factors, such as the amounts of ye'elimite and calcium sulfate available in CSAB cement. Moreover, calcium sulfate from an external source can also influence the expansi...

There has been a significant push in the direction of reducing carbon footprint of concrete through the development of alternative binders. To that end, calcium sulfoaluminate-belite (CSAB) cement is a promising alternative due to its lower carbon footprint and higher resistance against shrinkage cracking. Lower burning temperature and lesser amoun...

While cement production continues to increase globally, alternatives, such as alkali activated and geopolymeric binders, provide an important opportunity to diminish environmental concerns associated with production while retaining requisite physical properties. This work focuses on characterization and calculation of reaction product chemistry in...

An untapped source of amorphous SiO2, industrially generated Indian biomass ash (SA)—90% amorphous, with composition of ~60% SiO2 and ~20% unburnt carbon—can be used to produce cementitious and alkali‐activated binders. This study reports dissolution of amorphous Si from SA in 0.5 mol/L and 1 mol/L aqueous NaOH, with and without added Ca(OH)2, at S...

Biomass ash results from the combustion of agricultural residues, which, in many developing countries, are a primary source of power generation for small and medium size industries. This study focuses on the performance of a binder synthesized from an Indian biomass ash, Indo-Gangetic clay, hydrated lime, and aqueous 1M NaOH solution. To measure th...

Slags with varied amorphous and crystalline content, typical of iron and steel production, are generally underutilized. One promising reuse pathway for these wastes is chemical activation, producing alternatives to conventional building materials with lower embodied energy. The formation of a hardened binder is dependent on the slag mineralogy and,...

The Minerals, Metals & Materials Society 2019. Slags with varied amorphous and crystalline content, typical of iron and steel production, are generally underutilized. One promising reuse pathway for these wastes is chemical activation, producing alternatives to conventional building materials with lower embodied energy. The formation of a hardened...

Shrinkage cracking in concrete is a widespread problem, especially in concrete structures with high surface-to-volume ratio such as bridge decks. Expansive cements based on calcium sulfoaluminate phase were developed to mitigate the shrinkage cracking of concrete. The compressive stress induced due to restrained expansion of concrete has been shown...

Calcium sulfoaluminate (CSA) cements were developed for shrinkage compensation of concrete. The expansive nature of CSA-based cements can be used to enhance the resistance against shrinkage cracking by inducing compressive stress in concrete. Because of the higher water demand of CSA cement for achieving full hydration, as compared with ordinary po...

The application of pre-soaked lightweight aggregates (LWA) as an internal curing agent in concrete to reduce the cracking due to drying shrinkage is thoroughly studied in this report. It is determined that although LWA can significantly reduce autogenous shrinkage, its effect on drying shrinkage is minimal and in some cases it can even increase the...

ACI MATERIALS JOURNAL TECHNICAL PAPER Calcium sulfoaluminate (CSA) cements were developed for shrinkage-compensation of concrete. This study investigates the expansion characteristics of CSA-portland cement (CSA-OPC) systems in the presence of mineral admixtures (MA). Unrestrained expansion of CSA-based cement pastes incorporating Class C fly ash (...

Fresh and hardened properties of a suite of cementitious binders with cement kiln dust (CKD) as the main binding component (70% by weight) are evaluated in this study. Two CKDs with different chemical and physical properties were used in formulating CKD-fly ash (FA) and CKD-slag mixtures without portland cement. The setting time, workability, and s...

A clinker-free binder for making sustainable concrete was developed using cement kiln dust (CKD) and Class F fly ash. The CKD-activated fly ash binder developed a compressive strength of approximately 30 MPa after 48 h of elevated temperature curing. The mineralogical composition of the developed clinker-free binder was determined with the help of...