Cement: types, strength classes and makers in Tanzania

What cement is and how it is made

Cement is the binder in concrete, mortar and plaster: mixed with water, it hardens and holds sand and stone together. The 2025 annual report of Tanga Cement PLC, maker of Simba cement, describes the process at its plant in Tanga. Limestone is quarried, crushed and milled together with red clay into raw meal. The raw meal is burnt in rotary kilns into clinker, and the clinker is then ground with gypsum and limestone to make cement.

The same report says its packers fill normal 50 kg bags, 1.5-tonne jumbo bags and bulk tanker trailers. It also counts 13 plants competing in the market. The bag is the unit most buyers deal with, and its printed code is the first thing to read.

Cement types sold in Tanzania

Local makers label their products with the type notation of EN 197-1, the European standard for common cements. The share of clinker falls from type to type, and the rest is limestone, slag, pozzolana or other constituents. Composition ranges below come from a summary of the standard by engineer Muyiwa Ajumobi on Structville; the brand examples come from each maker’s own listing.

Cement types sold in Tanzania

Type	What it contains (EN 197-1)	Examples on the market in Tanzania	Maker’s source
CEM I, Portland cement	mostly clinker; up to 5% minor constituents	Twiga Ordinary (CEM I 42.5N)	Twiga Ordinary page
CEM II/A, Portland-composite	80–94% clinker; 6–20% another constituent	Nyati Super 42 (CEM II A-L 42.5R)	Lake Cement
CEM II/B, Portland-composite	65–79% clinker; 21–35% another constituent	Twiga Extra (CEM II B/L 32.5R), Twiga Plus and Simba Bora (CEM II/B-M 42.5N)	Twiga product pages; Tanga annual report
CEM III/B, blast-furnace	66–80% slag	Twiga Mega (CEM III B/SR 42.5N)	Twiga Mega page
CEM IV/B, pozzolanic	45–64% clinker; pozzolana, fly ash or silica fume	Simba Imara (32.5R), Simba Barabara (32.5N)	Tanga annual report

Not every bag carries an EN 197-1 code. Twiga Jenga is listed on the Twiga home page as MC 22.5X, a masonry cement, and Camel Cement’s four products are named on the Amsons Group page by strength class only.

Strength classes: 32.5, 42.5 and the N or R letter

The number on the bag is the strength band the product must reach at 28 days in a standard test, in megapascals. On the Structville summary, class 32.5 must land between 32.5 and 52.5 MPa, class 42.5 between 42.5 and 62.5 MPa, and class 52.5 at 52.5 MPa or more. The higher class also has a shorter minimum time before it starts to set: 60 minutes for 42.5 against 75 minutes for 32.5.

The letter after the class says how fast strength comes in the first days. N is normal early strength; R is rapid. A Finnsementti data sheet for a 42.5 R product quotes the requirement as at least 20 MPa after 2 days. Twiga presents its Plus Rapid product, made for block makers, as setting faster and raising production speed.

Which cement for which job

Tanzanian makers say in their own documents what each product is designed for. Their wording is the safest guide, and a structural engineer’s drawing always comes first when it names a class.

Which cement for which job

Job	What the maker recommends
Reinforced concrete: foundations, columns, beams, slabs, precast	Simba Bora 42.5N; Tembo Supaset 42.5N for bridges and high-rise work
Blocks, bricks, paving slabs, kerbs	Simba Imara 32.5R; Twiga Plus Rapid; Camel 42.5R
Plaster, forming and moulding	Twiga Extra 32.5R
Mortar for joints between precast elements	Simba Imara 32.5R
Road sub-base and soil stabilisation	Simba Barabara 32.5N; Camel 32.5N
Water-retaining structures and reservoirs	Simba Imara 32.5R

For concrete and mortar made with any of these, Kitovu has Polypropylene Fibre for Concrete and Mortar in stock in Zanzibar: by the supplier’s details, 12 mm monofilament fibre dosed at 0.9 kg per m³ for plastic shrinkage crack control.

What to check when you buy cement

1. The code on the bag. Match the type and class to the drawing or to the maker’s recommended use. A 32.5 bag is not a substitute where 42.5 is specified.
2. The maker’s documents. Twiga posts a monthly certificate for each product on its product pages; on 12 November 2026 the newest one was for September 2026.
3. The state of the cement. Ohorongo Cement’s storage guidance says lumps mean the powder has taken in moisture. Lumps that crumble by hand can still be used with a little extra cement in the mix; hard lumps are not fit for building.
4. How you will store it. The same guidance keeps bags on pallets or timber, never on bare ground or concrete, at most two pallets high, under a roof or sheeting, and used first in, first out. Stored that way, it says, the bags keep their properties for up to 6 months.

Who makes cement in Tanzania

The plants behind the main brand names in Tanzania, by their own sites and reports:

• Twiga — Tanzania Portland Cement PLC, Wazo Hill, Dar es Salaam: Twiga Cement grades.
• Simba — Tanga Cement PLC, Pongwe, Tanga: Simba cement by Tanga Cement.
• Tembo — Mbeya Cement, Songwe Industrial Area, Mbeya Region; part of Amsons Group, which also makes Camel Cement in Mbagala, Dar es Salaam.
• Nyati — Lake Cement.
• Dangote — a plant in Mtwara with a capacity of 3.0 million tonnes a year, operating since 2015, according to the investment authority TISEZA.

White cement is a different product with its own makers and uses, covered under white cement. Kitovu does not sell cement itself.